Newspaper Articles

Spectacular Sedums: Your New Favorite Groundcover

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By Abigayle Ward, UConn Dept. of Plant Science & LA Graduate Student

A bee on a cluster of pink sedum flowers
Sedums are very attractive to pollinators. Photo by dmp2024

With varieties native to North America, tolerance to frigid temperatures down to minus 40 degrees F, and nearly 500 species described, sedums subvert all expectations of a succulent. Also known as stonecrop, sedums have been a garden favorite since the 17th century, and it’s easy to see why. Their visual interest and tolerance of harsh growing conditions make them well-suited as groundcover for the landscaper with an artistic eye.

You can purchase either tall or creeping varieties of sedums. Also known as ‘clumping’ varieties, tall sedum varieties can grow up to 3 feet tall although many will only grow to 1 foot tall or less. Tall, top-heavy varieties can be prone to falling or flopping over especially if overfertilized or if they receive too much water. They are well-behaved perennials that are clump formers, and thus can be useful as focal points in garden beds. Alternatively, creeping varieties of sedums grow from 2 to about 6 inches tall.  These creeping varieties will spread a few feet in every direction but do so very slowly. If you wish to fill your bed with sedums, you can stick vegetative cuttings throughout the area you want them to grow. Keep moderately moist until well rooted. Once they root, they will usually fill out your bed fairly rapidly.

With such a large variety of leaf shapes and sizes, interesting bed textures can also be created with sedums. Some varieties have large, broad, spoon-shaped leaves while others have many short, pointed leaves surrounding the main stem. You may wish to combine different textures together into one bed to make a wild, visually striking design, or try taking advantage of certain textures for specific locations in the bed. For example, you could choose short creeping varieties with small leaves for bed edges, and select slightly taller creeping varieties with larger, broader leaves to build up to the bed’s focal point.

Variegated sedum with yellow flowers
Some sedums come in a variety of leaf shapes and colors. Photo by dmp2024

Sedums come in a smattering of delightful color combinations from electric green to deep purple, red to teal; there’s a color of sedum for any design. Many keep their color year-round, and produce delightful bunches of tiny, colorful flowers between summer and fall, depending on the species or cultivar. The magenta, yellow, and lilac-colored petals attract pollinators in great numbers, especially between August and September here in Connecticut. The flowers persist until wintertime, when they dry out and turn brown as the plant goes dormant. While you may choose to remove the flowers before the winter snowfall, you can also leave them on the plant to add some color contrast in your garden as the brown stalks are surrounded with snow. Additionally, leaving the dried flowers on the plants may help creeping varieties spread, as the tiny seeds fall to the ground and germinate come springtime.

While generally very tolerant of adverse growth conditions, sedums do best in sunny spots with well-drained soil. Luckily for those of us in Connecticut, many of our soils are well-drained. Sedums require little nutrients to thrive and typically are happy with just a spring application of an all-purpose garden fertilizer. Since sedums go dormant in the winter, no fertilizer should be applied later in the year. While other groundcover plants may need water in a drought, sedums, like most succulents, can go extended periods of time without supplemental irrigation. To top it off, their foliage is bitter, and thus unlikely to be damaged by grazing wildlife. The limited maintenance requirements of sedums make them attractive candidates for both lawn alternatives and green roofs alike.

While resistant to consumption by mammalian wildlife, the juicy sedum leaves are sometimes appealing to hungry aphids and thrips. To manage aphids and other sap-sucking insects, you can simply spray sedums with water to knock off the pests – just be mindful of overwatering, as the sedums may rot. Alternatively, you can try attracting ladybugs and other aphid predators to your sedums by planting marigolds, dill and other predator attracting plants nearby. The ladybugs will partake in the pollen and snack on the sapsuckers. Avoid spraying insecticides, as they will kill both pests and beneficial insects, including pollinators. Leaving leaf litter in your garden over the winter gives a place for ladybugs to hibernate. Come spring, newly hatched ladybug larvae will be on the hunt for a meal, ready to vigilantly defend your sedums from attacking aphids.

Your next groundcover selection can be both visually appealing and low maintenance. If you’re looking to update your groundcover, consider picking up some sedums at your local garden center in the spring or summer.

If you have questions on growing sedums or on other gardening topics, feel free to contact us, toll-free, at the UConn Home & Garden Education Center at (877) 486-6271, visit our website at www.homegarden.cahnr.uconn.edu or contact your local Cooperative Extension center.

Flock to Phlox

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By Dawn Pettinelli, UConn Home & Garden Education Center

Purple phlox flowers
Purple phlox in bloom. Photo by dmp2024

About now, many of our perennial gardens are looking a bit lackluster. Early summer bloomers have fizzled out and autumn charmers like asters and mums have yet to pop. Garden phlox (P. paniculata) to the rescue!

Annual and perennial phlox comprised about 70 different species, many of which are native to North America. Their habitats range from woodlands to meadow and their growth habits from low and mounded to tall and upright. All have clusters of tubular flowers that are exceptionally attractive to hummingbirds and hummingbird moths along with bees and butterflies.

There are an outstanding number of garden worthy cultivars. My favorite is ‘David’, a white, powdery mildew resistant variety that grows to about 4 feet with loads of slightly fragrant blooms. I have it planted in my white garden and this sturdy, upright plant has come back year after year with virtually no problems.

UConn Plant Science & Landscape Architecture professor, Dr. Jessica Lubell-Brand noted phlox ‘Jeana’, the 2024 Perennial Plant Association’s Perennial Plant of the Year, is treasured for its long blooming period as well as its butterfly luring abilities. Plants can reach up to 5 feet in height and its more loose and wild appearance works well in cottage gardens featuring attractive pink flowers and decent powdery mildew resistance.

Sometimes shorter varieties are a better fit and if that is the case, for your beds look to ‘Coral Crème Drop’, which according to Dr. Lubell are part of the Candy Store series. She raves about their vibrant coral blossoms with their August feel. Another top garden candidate in her book is ‘Glamour Girl’, also with hot coral blooms as well as good resistance to powdery mildew.

A number of garden phlox sport distinctive eyes. ‘Bright Eyes’, as the name implies is a delicate pale pink with a bright crimson eye while ‘Laura’ is a mildew resistant, royal purple variety with a white eye. Both grow to about 3 feet in height.

Many gardeners find these phlox indispensable for August into September color in the perennial garden. They are tough, colorful, vigorous plants that are hardy and relatively long-lived. They make excellent background plants for narrow borders and can bridge the gap between varied sized perennial plantings. Garden phlox come in a wide range of hot and cool colors ranging from white and light pinks, to purples, reds, oranges and magenta.

For healthy, vigorous plants, they should be grown in full sun to part shade. Phlox enjoy a moderately fertile soil with a pH in the 6s. While established plants are fairly drought tolerant, larger and more numerous flower heads are produced when adequate moisture is supplied. They grow at a moderate rate so division every 3 to 4 years is usually sufficient.

Both to encourage sizable blooms as well as to reduce the incidence of phlox’s number one nemesis, powdery mildew, Dr. Lubell recommends reducing the number of stalks early in the growing season to 6 to 8 per plant. This provides better air circulation to plants.

Powdery mildew on phlox leaves
Powdery mildew on phlox leaves. Photo by dmp2024

Powdery mildew is a fungus disease that is more widespread during humid, wet summers. It typically does not kill plants, but they look awful with their leaves covered with what looks like white powder. Two options for dealing with this disease according to Dr. Lubell, are to select resistant phlox cultivars or to pre-emptively spray with a least toxic substance like potassium bicarbonate or your fungicide of choice. As stems die or get killed by frost, be sure to remove them from the garden and put in the trash, not the compost pile.

Insects are not usually a problem but during dry, hot summers, spider mites may attack plants. Usually, a strong blast from the hose will knock them off. This may need to be repeated several times if dry weather persists.

A key gardening practice when growing phlox is dead-heading, or removal of spent flower heads. Garden phlox produce a lot of seeds and if left to fall to the ground and germinate, vigorous plants will most likely produce blooms in that undesirable, muted magenta color. Often these seedlings crowd out the more desirable cultivars that were intentionally purchased.

Not only are garden phlox cultivars pretty spectacular on their own but Dr. Lubell says they pair nicely with a variety of other perennials including lilies, yarrow, ballon flower, daylilies, bee balm as well as numerous annuals.

If you have questions on garden phlox or on any other gardening questions, feel free to contact us, toll-free, at the UConn Home & Garden Education Center at (877) 486-6271, visit our website at www.homegarden.cahnr.uconn.edu

Current Landscape and Garden Conundrums

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By Pamm Cooper, UConn Home & Garden Education Center

Here at the UConn Home & Garden Education Center we have been getting questions about three pests that have been particularly widespread in the state. Whether in the landscape or the garden, there is always something going on, good or bad, and keeping up with pests or perceived pests can be challenging. The following reflect the most common inquiries we have had over the past few weeks.

Asiatic garden beetles found in a spoonful of soil
Photo by Pamm Cooper

Asiatic garden beetles have been a real problem for many gardeners this year. An imported pest, these small, rusty brown, night-feeding pests can devastate plants overnight then disappear during the day. Leaving you to wonder what is eating your plants. Favorite plants include dahlias, basil, zinnias, sunflowers, peppers, eggplants and goldenrods. They will feed on over 100 herbaceous and woody plants. In the evening a plant can look great, and the next day it can be a skeleton of stems and leaf veins.

Check damaged plants at night with a flashlight; if they are active, you should find them. During the day, dig an inch or so into the mulch and soil under damaged plants. These beetles will hide there during the day. Some people have reported finding as many as 300 in a night, then 50 each night, until they find few or none. New beetles will fly in daily, so be vigilant. Feeding by adults should end by the end of August. Crush them or put them in a container of soapy water until they succumb. Foliage can also be treated with an appropriate insect control product that will kill them after they feed on the leaves, Read and follow label instructions carefully for any control products if they are needed.

Cicada killer holding a Cicada
Photo by Pamm Cooper

Cicada killers are rather mild-mannered (like Clark Kent) burrowing wasps that can cause alarm when they appear in the summer months. These wasps are very large, and females have the potential to sting, but have no aggressive nest-guarding instincts as do most other wasps or bees. What they have is size, and so become easily feared, especially when they burrow along sidewalks or other sandy areas close to pool, gardens and houses.

Female cicada killers burrow a rather rectangular tunnel deep into soft soils into which they will eventually drag a cicada they have paralyzed. They lay one egg on the victim and the larva will feed on the carcass and pupate over the winter. They may be a chronic problem in areas of sandy soils and can be discouraged by disrupting tunneling activity by drenching areas where they are actively tunneling with water. They do not like moist soils, so this may be the only control method needed. Digging may disrupt root systems of plants if the tunnels are made at the base of plants, and watering the plants affected in this way may settle the soil back around the roots. Use of any pesticide would only be effective if wasps are still going in and out of tunnels and should be used only if necessary.

The final pest we will cover are aphids. These piercing-sucking feeding type insects are small, but they can occur, seemingly overnight, in large numbers on plants. Aphids prefer newer growth like upper stems but are not so fussy later in the year when they feed on flower buds, old and new leaves and flower stems. Later in the summer some species may cover older stems right down to the ground. This is especially a problem on common and swamp milkweeds. Aphid feeding can cause wilting of plant parts above where heavy feeding occurs. Leaves can be mottled, then become distorted before turning brown.

Red aphids on a stem
Photo by Pamm Cooper

Control of aphids relies on paying attention every day. Aphid females can give birth to live young during the summer, often fifty or more new aphids appear from each female per day. This is why control seems effective, then before you can say “my plants look really good now”, there are scads of aphids back where they were before. Aphids in high numbers, especially on sturdy stems, can be crushed by hand, sprayed with a suffocating type product like insecticidal soap, or knocked off by a strong jet of water. Keep in mind that the reproductive females have wings, and they will take flight at the first sign of trouble. That is why they can persist on plants.

If aphids are a serious issue on plants, with no control measures apparently working, consider removing the affected plants and adding plants you know they so far have shunned as a food source. It may be a painful but necessary step.

Be alert to what is happening in your own backyard, for it is certain something, good or bad, is going on. The sooner you discover the bad, the better. Know that: “On every stem, on every leaf, and at the root of everything that grew, was a professional specialist in the shape of grub, caterpillar, aphis, or other expert, whose business it was to devour that particular part. “~Oliver Wendell Holmes

For questions about garden pests or any other gardening questions, feel free to contact us, toll-free, at the UConn Home & Garden Education Center at (877) 486-6271, visit our website at www.homegarden.cahnr.uconn.edu

What’s Eating My Brassicas?

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By Dawn Pettinelli, UConn Home & Garden Education Center

Broccoli, cabbage, kale and other members of the brassica family are tasty and so good for you but its not just us who find them delectable. Brassicas have a number of insect pests but probably several caterpillar species do the most damage.

A close up of caterpillar damage on broccoli leaves.
Caterpillar damage on broccoli. Photo by dmp2024

When checking plants, look for holes in the leaves. A few irregular holes may soon become a skeletonized leaf with only the midrib left if control measures are not taken. These caterpillars can quickly devour plants.

Two of the most common pests are the imported cabbageworm and the cross striped cabbage worm. According to Dr. Shuresh Ghimire, UConn Vegetable Extension Specialist, imported cabbageworm is the offspring of the cabbage butterfly, a butterfly with white wings with 1-2 round black spots on the forewing. Eggs, laid singly on leaves, are light green or yellow and slightly elongated. Three to 5 days later, the eggs hatch. The lime green velvety caterpillars feed for 2 to 3 weeks.

Dr. Ghimire noted that imported cabbage worm feeding and resting mostly occur on the underside of leaves. Be sure to check both the tops and bottoms of leaves. Damage includes round or ragged feeding holes and deposits of wet, green or brownish frass. There can be 4 to 5 generations each year. This pest overwinters as a pupae close to host plants.

Cross stripped cabbage worm
Cross striped caterpillar. Photo by dmp2024

The cross-striped cabbageworm used to be a southern pest but no longer. The adult moths fly at night so are seldom seen. Cross-striped cabbageworms are most abundant on late-season plantings says Dr. Ghimire. Unlike the other major caterpillar pests, such as cabbageworm and diamondback moth, the cross-striped cabbageworm lays its eggs in batches (3-25) rather than singly, so caterpillars emerge in clusters. Egg batches are yellow, flattened, overlapping like fish scales, and attached to the lower leaf surfaces.

The distinctive-looking caterpillars are bluish gray on top with green on their undersides, a yellow stripe on each side with a row of numerous black bands across the back. Clusters of these caterpillars are voracious feeders and plants infested with cross-striped cabbageworm larvae are often completely skeletonized, while adjacent plants may be left undamaged. There are 2 or 3 generations per year.

Two other caterpillar pests of brassicas are the diamondback moth and the cabbage looper. Eggs of these two pests are laid singly and most years they do not cause considerable damage to home vegetable gardens.

There are several strategies to control these caterpillars on broccoli plants. If you have just a few plants, check them every few days looking at both sides of the leaves and either squish any caterpillars you find or drop them into a can of soapy water.

A close-up of a leaf with chewing damage
Caterpillar damage on brassica leaves. Photo by dmp2024

Rotating your plantings and interplanting with flowers may confuse pests. Dr. Ghimire suggests planting flowers to attract natural enemies, like Braconid wasps, which lay eggs on soft-bodied caterpillars such as cabbage worms. The larvae feed inside the live caterpillars, weakening or killing them. Some plants known to attract pest predators include dill, parsley, hyssop and mints.

Since brassicas do not need to be pollinated, they can be covered with netting or row covers to exclude insect pests. The holes in the netting should be one-quarter inch. Hoops can be used to hold up the barrier or one can make wooden or PVC cages for a custom fit. Be sure to tuck or pin the edges to the soil so pests can’t crawl under.

Finally, if the caterpillar infestation becomes too extensive, Dr. Ghimire recommends Bacillus thuringiensis (Bt), which is a biological control for Lepidoptera species of moths and butterflies. Bt is a bacterium that when sprayed on your plants and consumed by the caterpillar enters the insect’s gut and causes it to die. While it is effective for controlling these pests, it is harmless to humans and other animal species. Limit its use to brassicas to prevent it from affecting desirable caterpillars.

As with all garden pests, the key to healthy plants is regular monitoring and putting control measures into practice when pests are first noticed. For questions on brassica pests or any other gardening questions, feel free to contact us, toll-free, at the UConn Home & Garden Education Center at (877) 486-6271, visit our website at www.homegarden.cahnr.uconn.edu

Coleus: A Victorian Dream

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By Abigayle Ward, UConn Dept. of Plant Science & LA Graduate Student

Red coleus in the middle of a flower garden
A bed of red coleus surrounded by magenta celosias, and baby pink and purple petunias, complete with a walking path dividing the bed in two. This circular bed is located at the end of Mansfield Road within the University of Connecticut Storrs campus.

Seen anywhere from great-grandma’s ornamental garden to your neighbor’s hanging basket, coleus are the colorful, velvet-textured leafy cousins of oregano and deadnettle. Native to tropical regions of Africa, Asia, and Oceania, it is thought that Dutch botanists introduced the fascinating foliage to Victorian England in the mid 1800s. Coleus were readily welcomed into homes as parlor plants and into ornamental gardens. They were especially coveted in so-called “carpet bedding” gardens, where bedding plants of equal height are used to create colorful designs such that they appear like “carpets” when viewed from above. Other than coleus, the Victorians enjoyed using colorful flowers such as petunias, asters, and zinnias as carpet bedding. Carpet bedding is still popular today; we have at least one such garden featuring coleus and petunias on display at the University of Connecticut Storrs campus. To design a carpet bedding garden, try combining simple shapes and lines to make symmetric, harmonious patterns. Use green vegetation, such as sedums, or even a green cultivar of coleus, to contrast with the bright colors of flowers and the mulch or soil below.

For those of us lacking yard space comparable to an English country house, a large carpet bed garden might be impractical. Instead, coleus can be planted alongside other flowers for a splash of color in a flower bed against a house or fence. Coleus are the perfect complement to the colorful clapboard siding characteristic of houses in New England – draw attention to the colors of both by putting reds with greens and yellows with purples. If coleus are planted directly into the ground, slugs are one major pest to look out for. In particularly wet summers, such as those in recent years, slug populations can devour entire coleus plants.

To avoid slugs, container gardens may be a wise option. Sitting above the ground and out of field soil, slugs will have more difficulty reaching the tasty, tender leaves. For those with outdoor space around their apartments, container gardens are also generally a renter-friendly option. Coleus grow well in window boxes and other small containers, and they can help add a warm, friendly atmosphere to the entrance of any home. Most cultivars of coleus available on the market today are tolerant of both shaded and sunny conditions, and thus are well-suited to either covered or open porches. In containers, the main pests to look for are thrips, mealybugs, and aphids. These three pests can cause discoloration in leaves, such as silvery/gold, yellow, or black spots. Outside where predators of these pests thrive, infestations should not progress to the point of killing entire plants, but affected foliage may be unsightly. While systemic insecticides may help keep these types of pests off coleus, they also can kill bees. Avoid applying systemic insecticides to coleus outdoors whenever possible. Try moderately forceful sprays with water instead, insecticidal soap or other least toxic controls.

The Victorians also kept coleus as houseplants, and so can you. In plant hardiness zones 6a-7b in Connecticut, coleus are very tender annuals. They will grow prolifically when temperatures are above 60°F, and will experience cold injury if temperatures fall below 50°F. When temperatures plunge below 40-50°F and overnight frost becomes a possibility, leaves will start to blacken and die. At the end of the growing season before the first frost, consider planting stem cuttings in pots and bringing them indoors for colorful, year-round foliage. Coleus as houseplants will do best in north-facing or east-facing windows. Avoid placing them in windows where they experience too much direct sunlight for too long during the day. If windows are unavailable, coleus also grow decently under grow lights.

No matter where they are grown, the main attraction of coleus is its brilliant foliage. Plants grown in containers may benefit from occasional nitrogen additions to keep them growing all season long. Like others in the mint family, coleus grow flower spikes when stressed or when the plant is near the end of its life cycle. While the flowers on the spikes are not very attractive from an aesthetic standpoint, bees, hummingbirds, and other pollinators flock to them. While the spikes can be pruned off if they appear too early in the growing season to encourage further vegetative growth, consider leaving the late-season spikes on, so that bees can collect nectar to sustain their hives over the winter.

While the selection of coleus cultivars were limited in Victorian England, decades of horticultural breeding efforts have given us access to over 1,000 varieties today, including sun-tolerant cultivars, with endless colors, leaf shapes, sizes, and growth habits. Consider adding this versatile Victorian dream to your home garden for splashes of colorful summer foliage.

If you have questions on coleus or on other gardening topics, feel free to contact us, toll-free, at the UConn Home & Garden Education Center at (877) 486-6271, visit our website at www.homegarden.cahnr.uconn.edu or contact your local Cooperative Extension center.

Great Hostabilities

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By Dawn Pettinelli, UConn Home & Garden Education Center

Hostas in a garden
Image by dmp2024

So versatile and ubiquitous are hostas that I have yet to visit a garden that doesn’t have at least one whether left by a previous gardener or selected by the present one. Hostas certainly are workhorses of the garden renowned for their shade tolerance, hardiness and longevity. Plus, few plants have such large variations in size, leaf color and texture. According to the American Hosta Society, there are more than 3000 varieties of hostas covering 45 species including stalwarts of our gardens such as Hosta sieboldiana, H. elegans and H. montana. Now the hostas you purchase are likely complex crosses of multiple species.

Hostas are native to Asia and came to the United States through Europe during the 1800s. Many of us older gardeners referred to them as plantain lilies because their broad leaves resemble a common weed (or herb depending on one’s perspective), plantain. The young leaves are reputedly edible. In fact, the Japanese are said to serve them raw, boiled or fried in tempura. Their palatability probably explains why gardeners around here half-jokingly refer to them as ‘deer candy’.

Hostas are divided by size into 5 groups. Minis are less than 6 inches tall, small range from 7 to 10 inches, medium from 11 to 18, large from 19 to 28, and giants are greater than 28 inches. ‘Gentle Giant’ and ‘Empress Wu’ are close to 4 feet tall with a spread of over 5 feet, if you’re looking for a plant to make a voluminous impression. Keep in mind a plant’s full size when incorporating them into your planting beds.

A notable feature of many hosta cultivars is leaf variegation. On marginally variegated plants the edges of the leaves are light in color, maybe cream or yellow. Medio variegated types have light colored centers with darker edges. There are also 5 groupings for color: green, blue and gold, plus the 2 types of variegation. The gold and variegated cultivars do best in part sun to dappled shade. Placed in a heavily shaded area, they can lose some of their color as only the green parts of the leaves photosynthesize.

Hosta leaves up close with raindrops
Image by dmp2024

Leaf shapes range from thin and smooth to ridged and heart shaped. Sizes range from 2 inches on ‘Mouse Ears’ to over a foot and a half on giant hostas.

While grown mainly for their attractive foliage, hostas do bloom once a year. Most have delicate-looking, tubular flowers in various shades of purple that are attractive to hummingbirds and bees. Fragrant white ‘Royal Standard’ grace part of a patio in my white garden. Their heady scent is especially pronounced on warm summer evenings. ‘Royal Wedding’ is another fragrant, white-flowering variety. Cut down the flower stalks once flowering is finished.

Growing hostas is a breeze. These tough, dependable plants put on their best show when not located in full sun as the large leaves can scorch during periods of hot, sunny weather. That being said, there are some cultivars like ‘Guacamole’ and ‘Paradigm’ which can tolerate full sun with adequate moisture.

An ideal location would be a semi- to fully shaded site in a soil with a pH in the mid 6s and moderate fertility. Hostas are often planted under trees as once established they can tolerate dry shade to some extent. Remember that a tree’s roots will be competing with the hostas and your plants would benefit from extra water and fertilizer.

The two major pests of hostas are slugs and deer. Ragged holes and tears on leaves are a sign of slugs. These soft-bodied creatures feed at night or on cloudy days but slime trails on the leaves or ground may be visible in the morning. Controls include hand-picking, beer traps, diatomaceous earth and slug baits.

Deer can make short work of a bed of hostas. Three strategies are to use repellents, fence them out or plant your hostas amid less appetizing plants. Some have reported less deer damage to blue leaved hostas, maybe because they have a waxy coating. If you’re growing hostas in deer country, you’ll have to figure out what works best for you.

At the end of the season, frost will flatten the leaves of your hostas. Cut them back and remove the foliage from your garden to give both slugs and diseases less places to overwinter. Plants typically need division every few years if they are outgrowing their allotted spaces. Dig up and divide in the spring when the new stems start to poke through the soil but before the leaves unfurl.

If you have questions about growing hostas or any other gardening questions, feel free to contact us, toll-free, at the UConn Home & Garden Education Center at (877) 486-6271, visit our website at www.homegarden.cahnr.uconn.edu

Calling the Cut – Tree Triage, Care, and Removal

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By Nick Goltz, DPM, UConn Plant Diagnostic Lab/UConn Home & Garden Education Center

The forecast is looking good for a perfect 4th of July weekend. Most folks will take advantage of the weather ahead to plan that perfect grilling menu for when their friends and family visit. This is a much-needed respite from the severe weather that passed through over the past few weeks. Severe winds and torrential rains hammered Connecticut and most of the rest of the Northeast after a recent heat wave. With the weather for the week ahead of us is looking much better than the weather of the week behind us, now is the perfect time to assess our trees and determine if any action needs to be taken before the next storm comes!

Tree with branches missing on one side.
Storm damage caused this tree to lose branches on one side. This lopsidedness increases risk to property below. Photo by H. Zidack

I’ll start and end this column with the advice that a professional arborist should be called-in if you are ever unsure of your tree’s health, or if you need support regarding safe management and potential removal. In Connecticut, one of the best resources for finding a licensed, local arborist as well as additional resources regarding tree care and maintenance can be found on the Connecticut Tree Protective Association website, ctpa.org. That said, tree triage can start with you at home. There are many things one can be on the lookout for to determine if a tree need professional attention, and potentially in what order the work should be done.

I’m sure you’ve heard this phrase used to describe real estate, but with trees too, location is everything. The first thing to consider when performing your tree triage is the location of the tree. Regardless of tree age, size, species, or health, the trees that should always merit our immediate attention are those in locations where they could pose a danger to life or property if a limb were to fall off or if the tree were to topple altogether. Trees within striking distance of homes, power lines, and important structures like chicken coops and pet houses should always be the first inspected before the storm comes and after it passes. If a tree knocks down a power line or hits a home, call for help. Never attempt to work around a live cable (one that still carries electricity) without the proper training and equipment.

The second thing to consider as you perform your tree triage is health of the tree. Trees weakened by disease or age are more likely to succumb to strong winds or topple after standing water weakens or kills roots. Inspect your trees for symptoms of stress and disease such as branches that no longer produce leaves. Depending on the species of tree, a few may not be much cause for concern, but if there are several branches on a tree that no longer produce new leaves or needles, the tree is likely not in great health. Another symptom of stress or disease is a visible canker, or large wound, on the trunk of the tree. Trees in good health will typically grow new tissue over an injury sustained by pruning, animal feeding, or a previous storm. Cankers that appear to be getting larger over a few years, rather than smaller, are often a cause for concern.

There are even some obvious signs of disease such as conk or shelf mushrooms that grow directly from the wood of the tree. While these organisms are important for nutrient cycling in natural ecosystems, they often indicate that a tree is approaching the end of its life. The shelf mushroom is only the sexual structure of the fungus, there to produce spores and reach new trees. While removing the mushroom may slow the spread of the fungus to other trees nearby, the majority of the “body” of the fungus will still exist within the tree, weakening it by breaking down woody tissue over time.

Trees, like other living things, do not live indefinitely and become more vulnerable to illness and stress as they age. Just like people need to take care of themselves to ensure they live a long, healthy life, so too must trees be cared for over the course of their lives to ensure they have the best possible outcome. Regular fertilization and pruning are essential to not only ensure that a tree grows robustly, but also that it does not become lopsided or heavy on one side as it ages. Even healthy trees can fall if they are never pruned and have a poor center of gravity! Pruning should be performed frequently to promote new growth, discourage lopsidedness, and allow increased airflow through the canopy. This will have the double benefit of decreasing disease pressure that often accompanies high canopy humidity and prolonged leaf wetness. Though it depends on the species of tree, most here in New England perform best when pruned while they are dormant in winter. Remember to not remove more than 1/3 of the tree’s branches when pruning, if possible!

There are other factors to consider when determining if a tree should come down that we don’t have space to discuss at length here, such as the species of tree, whether the tree is used for other purposes (such as part of a living fence), whether the tree has historic or personal significance, or what removal of the tree may mean for other plants nearby that depend on its shade. And, of course, nobody should consider tree removal without considering cost and time. If cost is a concern, remember to do your triage and prioritize the management of trees that could potentially damage your home, property, or power lines if they were to fall. These considerations and others are worth discussing with an arborist as they survey your property!

For questions about planting and pruning trees or other gardening topics, feel free to contact us, toll-free, at the UConn Home & Garden Education Center at (877) 486-6271, visit our website at www.homegarden.cahnr.uconn.edu or contact your local Cooperative Extension Center.

Remove Those Suckers!

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By Dawn Pettinelli, UConn Home & Garden Education Center

About now the gardens should be planted, and it is time to turn our attention to the trees and shrubs on the property. New growth is almost fully expanded and pruning of spring flowering shrubs can commence. When out there with your pruners, keep an eye peeled for suckers and water sprouts, both on the plants you’re pruning and other woody plants in the yard.

A pear tree with multiple suckers growing from the base. Photo by dmp2024

Many trees and shrubs produce vigorous, upright stems that can reach several feet high over the growing season if left unchecked. Those arising from the root system are known as suckers while those growths arising from the crown portion of a tree or large shrub are referred to as water sprouts. At the very least, they are unattractive and take away from the architectural framework of a plant. More importantly they use water, nutrients and energy that could be put to better use if not taken from the rest of the plant. If not removed, they can crowd out the main plant resulting in reduced vigor.

Some woody plants naturally tend to produce suckers and sometimes these young vigorous shoots are needed to rejuvenate older plants as aging stems are removed. An example would be shrubs like red-twigged dogwoods or lilacs. Suckers arising from trees such as apples, crabapples, honey locust, lindens and others, however, should be removed.

In the case of grafted plants, like hybrid tea roses or apples, the desired variety is grafted on to a rootstock that might be more cold hardy, have dwarfing genes or other desired features. Occasionally the rootstock revolts, so to speak, and sends up its own shoots. In the case of roses, one might notice a stem with red flowers when the plant was purchased as a named cultivar with different colored flowers.

Suckers and water sprouts often occur because plants are in some way stressed or due to damage to their root system. Plants can be under stress for a number of reasons. Some common reasons would be insect or disease problems, drought, too high of a water table, compacted soil and/or difficult growing conditions.

Planting too deep will also stress a plant and could cause suckers to develop. Whenever planting woody plants sink them so that the level of soil in the pot they are grown in is level with the soil they are planted in.

Another reason for suckers or water sprouts is that plants are pruned incorrectly or too drastically. Seldom is it advisable to remove more than one-third of the plant at one time. Also, avoid topping ornamental or woodland trees.

Ideally suckers and water sprouts should be removed as soon as they are produced. Often, they can just be rubbed or twisted off in spring as their stem is just starting to expand. Once they reach pencil-size in thickness, cut with clean, sharp pruners. Do your best to remove them flush to a limb or as close to the tree’s trunk or root system as you can. Don’t leave stubs as these will likely have buds at their base and just regrow.

Speaking of suckers, there are often questions when growing tomatoes about what to do with the sprouts popping up where the leaf attaches to the main stem. Typically suckers just form on indeterminate tomato varieties, which are those that continue to grow, bloom and set fruit as long as growing conditions allow.  If all suckers are left on the plant, it becomes quite unruly and hard to stake. Also, fruit will be plentiful but usually smaller.

Usually, the suckers below the first fruiting cluster are removed so the development of those tomatoes won’t be slowed. Then it is up to individual gardeners to decide whether to leave suckers or not and how many to leave. Often a few are left to increase and extend the harvest. Tomatoes in our area are prone to many leaf diseases, especially during humid and wet seasons. As the bottom leaves yellow and die, it is beneficial to let some of the suckers on top grow so plants can produce more foliage to yield food for the plant and to shade the developing fruit. Some experimentation might be necessary keeping in mind that it is better to remove too little than too much.

For questions about pruning suckers and water sprouts or on other gardening topics, feel free to contact us, toll-free, at the UConn Home & Garden Education Center at (877) 486-6271, visit our website at www.homegarden.cahnr.uconn.edu or contact your local Cooperative Extension Center.

Firefly Petunias Light Up the Night

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By Dr. Matthew Lisy, UConn Adjunct Faculty

A pot of white flowered firefly petunias
Firefly Petunias by Day. (Photo by M. Lissy)

The world of genetics has really had a tremendous impact on our lives. There is a lot of talk about GMOs, or genetically modified organisms, in the news. Labels even alert us to the presence of these crops in our foods. I wanted to share a new plant called the Firefly Petunia. It was not fireflies, but mushrooms that gave this plant its ability to glow. This is known as bioluminescence in the world of biology.

Through feats of genetic engineering, a gene is taken from one organism and placed into another.  This is where people become worried. Humans, however, have been doing this for hundreds of years. The best looking or most productive organisms were bred together for the next generation.  This is called selective breeding, and it essentially concentrates beneficial versions of genes in the offspring.

Now what is determined to be the most beautiful is truly in the eye of the beholder. Some people, for example, selected for white flowers in a normally purple flowered species, Echinacea purpurea. Some have even taken things a step farther and crossed different species of plants to obtain new colors of flowers. In nature, separate species have evolved isolation mechanisms to maintain their identity. When our plant breeders force a cross of the species boundary, much of the time it was done with closely related species of plants within the same genus.  A great example of this is the crossing of Echinacea purpurea, the purple cone flower, with Echinacea paradoxa, the yellow cone flower. This was done to obtain hybrid offspring that have red or orange flowers. These were back crossed with the parent varieties, so they have the same growth habit and form, but with new colored flowers.

Firefly petunia flowers glowing green in the dark.
Firefly petunias by night. This is no trick, the plants actually glow (photo by M. Lisy)

This hybridizing never really ruffled many feathers though, as the plants were very closely related anyway. More modern GMOs, like our Firefly Petunias, are obtained not through “natural” pollination processes, but through genetic manipulation. Scientists literally take one or more genes from one species and place them in another. These species are not closely related, so it may become an ethical conundrum. Here, one may ask if we should take a gene from a mushroom and place it into a plant. A similar circumstance was seen over twenty years ago in the aquarium industry, where genes from corals and jellyfish were placed into tropical fish to make them fluorescent Glofish.

On the question of ethics, I cannot tell you what to think, or what is right or wrong. We each will need to answer that question for ourselves. It does remind me of a quote from Jurassic Park, where Dr. Ian Malcolm states “…your scientists were so preoccupied with whether or not they could that they didn’t stop to think if they should.” The real question is where do we go from here. For the fish, it was species after species of Glofish, and for me, the novelty started wearing off. After all, how many species will be made fluorescent before it just gets boring? Now for our plants, will we have roads lined with glowing trees to eliminate the need for streetlights? Will we have glowing houseplants that function like night lights? Ultimately, it will be up to you, the consumer.

For me, this is just cool science. We ship and plant petunias all over the world. Are these glowing petunias going to cause any harm? Probably not, as none of the other ones have. When I go outside at night to take the dog out and see the bioluminescent petunias, it puts a smile on my face. It reminds me of the fact that we, as humans, are capable of many things. I can’t help but ponder if this will inspire a sense of awe and wonderment in our children. Maybe some may even study genetics because of these petunias. What if one of them ends up finding a cure for a debilitating human disease, all because of a glowing plant? And while some may say that this daydream of mine is just science fiction, need I remind you that so were glowing plants a few years ago?

For your gardening questions, feel free to contact us, toll-free, at the UConn Home & Garden Education Center at (877) 486-6271, visit our website at www.ladybug.uconn.edu or contact your local Cooperative Extension center.

 

Seen any Sawflies?

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By Dawn Pettinelli, UConn Home & Garden Education Center

Hibiscus sawfly larvae on hibiscus leaf. Photo by dmp2024

Gardeners know that amidst the promises of each new growing season come its challenges, usually in the form of weather or pests. A common insect pest this time of year are sawfly larvae, which feed on some of our favorite plants including roses, azaleas, perennial hibiscus, dogwoods, and some pines. If populations are high, significant damage can occur.

Sawfly adults are small, short-lived insects slightly resembling wasps to which they are related but their waists are generally thicker. Their ovipositor (egg-laying appendage) is somewhat saw-like in appearance, hence their common name. Eggs may be laid singly or in groups.

Larvae look like small caterpillars but there is a distinctive difference between caterpillars in the Lepidoptera family that transform into butterflies and moths, and sawfly larvae in the Hymenoptera family. Larvae in both families have numerous pairs of legs. From the head, the first three pairs are thoracic legs that correspond to an adult insects’ three pairs of legs. Count the number of fleshy leg pairs (pro-legs) after that. Caterpillars have 5 or less pairs while sawfly larvae have 6 or more.

Rose slug damage on rose leaves
Rose slug damage on rose leaves. Photo by dmp2024

Check your rose bushes for rose slugs, a common name for at least 2 species of sawflies whose larvae may be feeding on your plants. One is thought to be native to the U.S. and the other accidentally introduced from Europe. Both were noticed as pests in the Boston area over 100 years ago and do similar damage to rose foliage.

The small green caterpillar-like larvae that may be ½ to ¾ inch long depending on the species skeletonize the leaves and only the veins remain. They can feed for several weeks if not controlled and move to the undersides of the leaves during the day making them hard to spot. One or two generations may be present each season, again depending on species. Mature larvae will pupate in the soil below plants, where they overwinter and will reemerge the following spring.

Hibiscus sawflies feed on members of the mallow family with the most common one in this area being the large-flowering perennial hibiscus. The green larvae are small, and also can be found on the undersides of leaves where they often go undetected until large leaf areas are consumed.

There are at least 3 species of sawflies that feed on azaleas in this area. The small green larvae have tannish heads but are hard to spot at first as they feed on emerging foliage. Keep an eye out for foliar feeding at the edges of the leaves. The larvae are less than ½ inch in length and feed until late June or early July. There is only one generation per year and these larvae will also drop to the ground to pupate and overwinter in the soil below plants.

Pine sawfly species seem to prefer Mugo, Scots and red pines although they can feed on others. Some are inadvertently introduced pests like the European pine sawfly. Since they were first noticed around 1925, they have become widespread pests. The larvae may be up to an inch long and is grayish-green with mostly darker parallel stripes. Red-headed pine sawfly larvae have red heads as the name indicates but has a yellow body with black spots.

Pine sawfly adults typically lay groups of eggs so multiple larvae hatch and feed in groups. They have a very distinctive defense mechanism when disturbed. Most curiously they rear up and ‘wave’ as you wave your hand over them. This does discourage insect, avian and vertebrate predators, at least to some extent.

Dogwood sawfly females can lay more than 100 eggs on the underside of their preferred grey dogwood host plant. Larvae can consume the whole leaf as they mature leaving only the large midvein. Young larvae are translucent and yellowish but develop black spots and become covered with a white powdery coating as they mature. Their appearance can make a gardener think there are two species of insects attacking plants rather than one. When mature, the larvae seek out an overwintering location with rotted wood on the ground being preferred.

Regardless of which species of sawfly is attacking your plants, options for control include hand picking, insecticidal soap, Spinosad or other insecticides labeled for sawflies. While Bacillus thuringiensis (BT) can be used for caterpillars in the Lepidoptera family, like cabbageworms and Eastern tent caterpillars, it does not work on sawflies.

If you have questions on identification or control of sawfly larvae or any other gardening questions, feel free to contact us, toll-free, at the UConn Home & Garden Education Center at (877) 486-6271, visit our website at www.homegarden.cahnr.uconn.edu