Author: Zidack, Heather

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.

Thinning Fruit, Smart Harvesting, Night Time Feeders & Other July News

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July is for Thinning Fruit, Smart Harvesting & Night Time Feeders

"A perfect summer day is when the sun is shining, the breeze is blowing, the birds are singing, and the lawn mower is broken."
- James Dent

 

Fruit Thinning

Thinning fruit on branch
Photo by Lisa Catalano

Most home gardeners who grow fruit trees know the importance of pruning for better air circulation, pest and disease control and for better quality of fruit.  Thinning fruit early in the growing season is equally important for the same reason.    In addition, it reduces a biannual fruit set.  If fruits are left alone on the branches, the trees will use its carbs to produce all the fruit in one year exhausting its stores to produce fruit the next.

Read More About Fruit Thinning

Smart Harvesting

A bucket of cut flowers and a basket of harvested veggies
Photo by H. Zidack

    July is often the month when we start harvesting vegetables and cut flowers from our gardens! Use these tips to make sure you're getting the most out of your home production.

    Tips for Harvesting Vegetables

    • Harvesting early in the morning will help increase shelf life and may even improve taste.
    • Never tug on your plants - use pruners or scissors to remove stubborn vegetables.
    • Harvesting tomatoes before heavy rains can reduce chances of splitting.
    • Know your vegetables and harvest at the right stage of development! Picking too early or leaving things too long can lead to reduced quality.
    • When harvesting garlic, use a trowel or other garden tool to help you pop the bulbs out of the ground. This allows you to avoid damaging the stem while you're pulling.

    More Tips for Harvesting Vegetables

    Tips for Harvesting Cut Flowers

    • Cut early in the morning when plants are well hydrated.
    • Carry a bucket of fresh, clean, water to collect freshly cut flower stems.
    • Know your plants - different species of flowers may need to be cut at different stages of development.
    • Sanitize buckets and tools (knives, shears or purners) between uses.
    • Make sure cutting tools are sharp so as not to crush vascular tissues when harvesting.
    • Never store flowers in refrigerators that have food in them. Ethylene released by vegetables can speed up the bloom's decline.

    More Tips About Harvesting Cut Flowers

    Night Feeding Garden Pests

    One of the most frustrating things for gardeners is walking through our beds and seeing damage that "wasn't there yesterday!" Many culprits feed at night or in the early evening when we're having dinner and settling down for the day. Learn more about them to help you catch the culprits red handed this summer!

    Asiatic Garden Beetles

    Asiatic Garden Beetle on damaged leaves at night

    These non-native rusty brown scarab beetles feed on plant foliage and flowers at night. Scout with a flashlight to look for them. They can destroy basil plants overnight and may be hiding in mulch or just under the soil surface at the base of plants they are feeding on.

    Earwigs

    Earwig damage on leaf

    Earwigs feed on plants and flowers at night and hide during the day where it is dark especially in mulch or under plant containers where they are feeding. Foliage can be sprayed with an appropriate product, so they ingest it when feeding. Do not apply products to flowers.

    Slugs

    Snail on grass

    Slugs can leave shot hole like damage from chewing, and you will often also see trails left from where they have been. They are very active during wet/rainy weather.

    Deer/Fawns

    Fawn in the grass

    If deer repellents were used earlier in the year repeat applications now as fawns will be browsing and they may not have been exposed to both desirable plants and effective repellents yet. Teach them when they are young to avoid plants their mothers preferred.

    Rabbits

    Rabbit looking through garden fence

    Rabbits can feed day or night, but normally are more active toward evening and nighttime. Favored plants can vary. Cage plants at night that they are eating, or simply throw bird netting over them at night.

    Native Highlight: Coral Hairstreak Butterfly & Native Wood Lily

    Coral Hairstreak butterfly on flower

    The coral hairstreak butterfly flight period coincides with the start of flowering of our native wood lily Lilium philadelphium. These small butterflies are often seen getting nectar on the flowers. Male butterflies also patrol their territory using the flowers as their base of operations. Wood lilies can be found in bloom around July 4th in Connecticut.

    Learn More About Lilium philadelphium

    Learn More About Coral Hairstreak Butterfly

    Vegetable Gardening Resources

    During the growing season, UConn Extension publishes a regular pest alert. Additionally, the New England Vegetable Management Guide offers a lot of information about specific vegetable crops.

    While the target audience for these publications is usually commercial growers, home gardeners can learn a lot from these materials including identification and management of common pests in your veggie gardens!

    If you ever need confirmation on an ID or have additional questions about what you read in these reports, please do not hesitate to reach out to us at the Home & Garden Education Center! We're happy to help your gardens thrive.

    6/28/2024 Vegetable Pest Alert

    Read Previous Pest Messages

    New England Vegetable Management Guide 2023-2024

    UConn Fruit Update

    The UConn Fruit Program publishes a fruit update, very similar to the IPM Vegetable Pest Alert. If you keep fruit trees, this may be a valuable resource for you! If you ever need help understanding how to apply these principles to your own home garden, let us know!

    Read the Latest UConn Fruit Update

    New England Tree Fruit Management Guide

    July 2024 Weather Outlook

    A seasoned gardener always keeps their eye to the sky at any time of year! NOAA's National Weather Service released their discussion about how weather patterns in July will continue to lead us into the growing season!

    July Precipitation Outlook Map July Temperature Outlook Map

     

    Upcoming Events and Things to Do

      • July is when we often see many local events including local fireman carnivals, farmers markets, and town celebrations.

      Educational Opportunities & Workshops

            • CT Rocks Geology Workshop - July 27th, Hampton, CT

            Upcoming UConn Educational Events

            3rd Annual IPM For Home Gardeners Seminar August 3rd

            UConn IPM For Home Gardeners Seminar 
            Saturday, August 3, 2024
            9:00 a.m. - 1:00 p.m
            W.B. Young Building
            Storrs, CT

            Register for the IPM Seminar

            CT Invasive Plant Working Group
            In-Person Symposium
            October 29th, 2024
            UConn Student Union
            Storrs, CT

            cipwg.uconn.edu

            July Gardening Tips

             

              • Many plants will shut down temporarily during times of high heat and drought. This can reduce flower/fruit/vegetable production. Check the soil for moisture to avoid overwatering.
              • Do not mow during times of drought, this can damage your turf. Only mow when lawns are actively growing.
              • Squash vine borer moth on LantanaClosely monitor for Squash Vine Borer and Squash bugs on your cucurbits!
              • Check hummingbird feeders for mold, ants and other problems every week. Cane sugar solutions may need more frequent attention. There are some products resistant to mold and nutrient breakdown - please check the label for frequency on these products.
              • Many gardeners will be harvesting fall planted garlic in the month of July. Allow bulbs to cure for a minimum of 2 weeks.
              • Cut back mums, tall asters, Montauk daisies and helianthus by about one-quarter for bushy, more floriferous plants.
              • Pinching back herbs to stop flowering will keep the best flavor in the leaves and encourage branching. Herbs can be air dried, dried quickly in the microwave, or frozen.
              • Sunflower seeds can be sown before mid-June - mid August, depending upon days to maturity on the seed label which can vary from 60 to 110 days. If planted too late, plants will not have time to bloom before OctoberCalibrachoa in planter on a table
              •  Calibrachoa are stunning annuals that are excellent in hanging pots. They are heavy feeders and need moist soil, Watering can be done daily, but make sure not to saturate soils as these plants will succumb readily to root rot, especially in hot weather.

               

              More July Gardening Tips

              This Month’s Newsletter Contributors: 
              Pamm Cooper, Dr. Nick Goltz, Dawn Pettinelli, Marie Woodward, Heather Zidack 

               

              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

               

              Keep your Perennials & Annuals Looking Fabulous All Season Long!

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              By: Heather Zidack, UConn Home & Garden Education Center

              Geraniums and other flowers in a mixed container
              Geraniums benefit from regular deadheading. They’re great for beginners because it is easy to tell the difference between new and spent flowers. Photo by H. Zidack

              Hanging baskets, planter boxes and perennial gardens that are bursting with color are seldom planted in spring and left untouched until autumn. Deadheading, pruning, trimming and pinching are all techniques that gardeners can use to get that perfect look all season long. While it may be intimidating, this simple task can result in a huge visual impact with only a little effort. Through a series of pruning techniques, we manipulate our perennials and annuals to give us the most beauty we can get out of them in such a short season. It is important to recognize that cutting healthy flowers or shoots can help plants in the long term – no matter how much it may pain us as gardeners to do so.

              Deadheading is a widespread practice where gardeners remove flowers that have gone by. One of the first things to become aware of is the difference between a bud and a spent bloom on the plant you are working on. Many gardeners will snip petunia buds, mistaking them for spent flowers. It is important to be vigilant with these cuts. Remember that your plant's goal is to reproduce, and they use flowers to do so. By removing the flowers, you are stopping the plant from producing seed and encouraging it to restart the cycle – meaning more flowers for you!

              Some gardeners will select “self-cleaning” varieties of annuals that will shed their flowers without the need to deadhead all summer long. In general, these may not produce seed; therefore can easily restart the process themselves.

              The whole practice of deadheading, pinching and trimming herbaceous plants can be boiled down to redirecting the plants energy into different purposes. Where deadheading helps to clean spent flowers, pinching will remove new buds before they bloom. If you want to encourage beautiful single stem cut flowers, for example, you may decide to pinch lateral (side) flower buds to force the plant to put all its energy into a single bloom at the top. Alternatively, pinching the terminal (top) bud will give you many smaller flowers on one stem, creating a fuller appearance.

              This same principle applies to pinching shoots of herbaceous plants to make them fill out more. Cutting further down a stem will again remove that terminal bud and cause the plant to focus its energy on new shoots that come from nodes further down the stem. Think of how full your basil plants flush out when you harvest fresh herbs.

              Torenia hanging basket
              Torenia is considered a self-cleaning annual that is great for shade and is loved by hummingbirds! Photo by H. Zidack

              Often, gardeners will notice that in mid to late summer their hanging baskets will start to look “tired.” They may notice prolific flowering on the ends that hang down, but often see that the center of the basket is not as full or may even be dying out. The first thing to check for is to make sure that you are watering them regularly. Because hanging baskets are suspended in the air and uninsulated, they will dry out faster. When you are trimming herbaceous plants for growth you can take one third of the plant volume away at a time, safely. Think about it as playing hair stylist! Cut back one third of the longest growth at the ends, and watch new growth come from the roots. It may also help your hanging baskets to remove any branches that have been shaded or dried out in the interest of “lightening” the growth that is hanging down.  Again, you may lose flowers for a week or two – but the result down the road will be beautiful!

              For perennial gardens, June is a wonderful time to do some pruning as well. Cutting back early flowering perennials can encourage a second flush of flowering in some species. This works exceptionally well for plants like Salvia, Nepeta, and Lavender. Deadheading throughout the season will help plants like roses and Echinacea continuously flower. And pinching can help perennial mums form their shape for the fall.

              Summer is a stressful time for plants! Disease, pests, and extreme weather can all contribute to a stressful environment. Our New England summers can promote these pressures with high heat and humidity levels. During these times, pay careful attention to your watering habits and adjust, as necessary. In times of drought or excessive heat, plants will use water faster for hydration and cooling, just like we do. Being aware of this can help you know when to check for water and help you be more diligent with your watering practices. Using a balanced, water-soluble fertilizer can also promote plant health and reduce stress in perennials and annuals. This is why it is great to fertilize after pruning and deadheading. If you need more information on trimming, watering, fertilizing, 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