Newspaper Articles

Plants Enjoy Summer Too!

Posted on June 21, 2025June 25, 2025 by Zidack, Heather

By Dr. Matthew Lisy, UConn Adjunct Faculty

A monstera adansonii with yellowing, curling and damaged leaves — This Monstera adansonii, that was sunburned. The damage can take weeks to fully appear, first starting as faint yellowing, then brown dead tissue (photo by M. Lisy).

A summer vacation can be beneficial for our houseplants provided that we pay attention to some abiotic (nonliving) factors. Plants need time to adapt to new growing conditions or they can have deadly consequences. Try and make the change as gradual as possible. I usually wait until the end of May, where temperatures are consistently in the 70s for the highs, and no lower than 50s for the lows.

Our plants cannot go from dim, indoor lighting to super bright full sun outside. Any leaves subject to this will burn and die. The best way to acclimate plants to life outdoors is to place them in the shade of a large tree for about a week, and then gradually expose them to some direct sunlight. At first, start with only an hour or two of sun, and then add a bit more the following week until you transition them to full sun. This is assuming that the plants in question are ones that need full sun. Cacti and succulents can generally be transitioned to full sun (one notable exception are the forest cacti).

Most of our houseplants are actually forest-floor species or epiphytes (these grow and live on the trunks of other trees). Either way, those two groups of plants grow in the understory shade of a larger tree in nature, and do well there over the summer. Some plants I saw recently for sale were called neon philodendron. These have light green leaves (similar color to neon pothos). The light was so intense that it bleached the leaves to a pale-yellow color, and some were turning brown. The plants looked miserable, and the grower said she was going to move them to a shadier location.

I am not sure why we cannot have normal weather, but it seems we have had either too dry or too wet the last five years. When it rains consistently, it keeps our plants in a constantly moist state, which leads to root rot. I lost a few really nice philodendrons due to them being too moist in last summer’s constant rain. The ideal setting would have the plants exposed to good light while under cover. This way, the gardener can water them appropriately based on the needs of each plant. If this is not an option, repotting and adding some extra perlite to the mix will help the pot shed the excess water. Be sure to remove the saucer from the pots and hanging baskets while the plants are outside. These will hold excess water and keep the plants in a constantly moist state and favor fungal infections.

A pot or hanging basket may only have about a gallon or two of soil at best, and will dry out quickly in the heat. Depending on your soil type, it may be almost impossible to water enough. Try to avoid full sun in the hottest part of the day between noon and 2:00 p.m.

In an exposed location, wind can rapidly desiccate, windburn, or break plants. A good friend of mine with a large houseplant collection in the Midwest had almost everything he owned blown over and damaged when a tornado swept through his town last summer. Although he did not experience a direct hit, the winds were so bad it ruined many of his mature plants. I told him to look at it like an unintentional propagation event. When vining plants are grown in hanging baskets, they sometimes start to cling to the branches around them and rip in the wind.

Hopefully this article will help plants enjoy their summer vacation. It is a great time for plants to grow and be propagated. Be careful of the extremes of summer, and give the plants a gentle exposure to the outdoors.

The UConn Home & Garden Education Center supports UConn Extension’s mission by providing answers you can trust with research-based information and resources. For gardening questions, contact us toll-free at (877) 486-6271, visit our website at homegarden.cahnr.uconn.edu, or reach out to your local UConn Extension center at cahnr.uconn.edu/extension/locations.

Put an End to Blossom-End Rot: Water and Nutrient Management is Key

Posted on June 15, 2025June 16, 2025 by Zidack, Heather

By Nora Doonan, UConn Soil Science Graduate Student, Department of Plant Science & Landscape Architecture

5 ripe tomatoes — Photo by Julie-Ann Adorno, Soil Science Graduate Student, UConn Plant Science & Landscape Architecture

It can be frustrating to put time and energy into growing tomatoes, only to find that your tomatoes have developed blossom-end rot. Blossom-end rot is a physiological disorder that commonly affects tomato plants, characterized by a black, sunken spot on the fruit. This disorder is caused by insufficient calcium as a result of nutrient and water management challenges. Blossom-end rot can also affect peppers, eggplants, squash, and watermelons. In tomatoes, it is commonly seen on larger and elongated varieties, which can have a greater demand for calcium. Calcium is an essential plant nutrient that is required for proper growth, especially for the development of cell walls in the tomato fruit. When a fruiting tomato plant experiences calcium deficiency, the cell wall can collapse and show the appearance of blossom-end rot. Soil tests can reveal if your soil has sufficient levels of calcium and can determine if your soil pH is optimal for nutrient availability.

Oftentimes, the soil is sufficient in calcium levels, but blossom-end rot still occurs. Blossom-end rot can be closely associated with soil moisture that is too wet or too dry. The soil should never dry out completely. It is important to water regularly to ensure that plants receive 1 to 2 inches of water a week. A cycle of dryness followed by overwatering is only promoting calcium deficiency in the plant. If soil is too saturated, there may be insufficient oxygen levels in the soil that can affect the roots’ ability to take up water and nutrients.

One method of maintaining optimal soil moisture is to mulch tomato plants with an organic mulch, such as wood chips or straw, after the soil has warmed up. This will help to prevent excessive evaporation and drying of the soil. Another method is to plant tomatoes in a mound of soil that is high in organic matter or compost. Organic matter can retain soil moisture and provide adequate drainage.

There are other factors that can affect calcium uptake by the plant, such as high concentrations of ammonium, potassium, and magnesium in the soil. This can be caused by over fertilization. Specifically, over fertilizing with nitrogen can promote excessive production of leaves in the tomato plant, which can preferentially distribute calcium to the leaves rather than the fruit.

Calcium movement in the plant is dependent on transpiration, which is the loss of water to the atmosphere from plant leaves, stems, and flowers. Calcium is taken up through the roots and relies on water flow through the xylem for transport through the plant. This movement of water through the xylem is driven by the process of transpiration. Calcium is not redistributed from the leaves to the fruit. In addition, the overfertilization of ammonium, potassium, and magnesium can allow for competition in root uptake of calcium because they are all positive cations. Damages to roots, caused by fertilizer burns or cultivation, can also be a factor in impairing nutrient and water uptake. To prevent blossom-end rot through fertilization practices, apply fertilizer as recommended by a soil test and apply nitrogen fertilizers in the form of nitrate, rather than ammonium.

Any affected fruits can be removed from the plant, as they will continue to drain moisture and calcium for development from other fruits. A foliar application of calcium can be made to the leaves when the fruit is young, but it is not the most effective method, since calcium in the leaves is relatively immobile. The goal is to prevent the need for foliar application through water and nutrient management across the tomato plant growth stages. Hopefully these methods will allow you to prevent blossom-end rot starting at beginning stages of growth, so that you can enjoy a bounty of beautiful, red tomatoes.

Put in the Work Now for Lasting Garden Beauty

Posted on June 7, 2025June 10, 2025 by Zidack, Heather

By Heather Zidack, UConn Home & Garden Education Center

If you’re planning to do some landscape renovations this summer, you will often hear the suggestion of doing certain tasks “until the plant is established.” If you’ve heard this phrase and wondered what the pros mean, you’re not alone. It’s crucial to understand that the first year of growth is one of the most critical to ensure the success of trees, shrubs and perennials in the landscape.

The “establishment period” is when a newly transplanted plant pushes roots beyond the original root ball to anchor itself into the surrounding soil and adapt to its new environment. Establishment happens in as little as 2-4 weeks for your veggie starts and other annuals. However, if you are installing woody ornamentals or perennials, it is recommended to provide support for their first year in the landscape. Some species, especially fruiting plants may need longer attention to ensure establishment and landscape success.

Keeping the plants properly hydrated is going to be your first line of defense in preventing transplant shock. Using sprinkler systems for supplemental water can be problematic for trees, shrubs and perennials. These systems, especially those designed for lawns, maintain moisture in the top 1-2 inches of soil. Our non-turf plants need much more. Providing adequate water will help new plants acclimate by providing sufficient hydration, but it will also encourage the root system to expand. Roots pull moisture and nutrients from the soil but also act as an anchor to keep the plants upright. Keeping only the top few inches of soil moist will encourage roots to stay in that shallow layer instead of expanding deeper into the soil, hindering the development of that anchoring system. Additionally, watering demand tends to be more frequent with shallow root systems, as the first few inches of soil are more susceptible to drying out on sunny days. Lastly, the shallow roots need to compete with established turf for resources at a 1-2-inch depth.

While in this establishment period, the standard watering recommendation is 1-2 inches per week, depending on the species of plant. An inch of water is equivalent to 0.62 gallons per square foot of garden area. Watering the plant at this rate encourages it to stretch its roots downward into the soil. With deeper roots, plants can find moisture even during times of temporary drought deep below ground. This is a huge contribution to drought tolerance, as opposed to the common belief that the plant will just “live longer without water.”

If the forecast does not predict an inch of rain within the week, gardeners should be out checking the soil for moisture a few inches down and providing supplemental water if necessary. Always check the soil before watering, especially if you are new to gardening. Squeeze the soil in your hand. If the soil particles stick together easily, it is likely that there is enough moisture. If soil clumps fall apart between your fingers or the texture is dusty, the soil is too dry and more water is needed. If you can squeeze water out of the soil like a sponge, there is too much moisture, and you should come back and check in a day or two. Overwatering can lead to root rot and other diseases and finding the balance is a fine-tuned skill developed over time.

Monitor your new plantings for the first year and watch for signs of transplant shock, pests and disease so that you can adjust quickly and keep your plants healthy during this time. While transplant shock is a normal response to being planted in a new location, the symptoms can be startling to gardeners. Remember that the UConn Home & Garden Education Center is here to help you determine if you are looking at transplant shock, disease, or possible pest damage. It’s easier to catch and treat issues earlier than it is to react at the end of the season. If you’re vigilant, we can help you find your way to solutions much more quickly!

Staking should only be done as a temporary measure for young trees where the environment or the species of tree requires extra support. In most cases, trees should be perfectly capable of supporting themselves. Exposure to the elements, like the occasional strong breeze, can help to strengthen them as they adjust. However, temporary staking can help take some of the stress off the young trees if they are establishing in harsher environments. While there are many situations that may be appropriate, consider staking newly planted trees when they are in open areas, have high wind exposure, or are in an area that risks mechanical or physical damage. Staking may also be appropriate if the root ball is significantly smaller in relation to the tree’s size, or if the tree has a top-heavy canopy.

Once your plants are well anchored into your landscape, they will be able to find water and nutrients on their own while standing tall in the face of our New England climate. Putting in the attention and care to help plants establish in their first year or two in the landscape will reward you with many years of enjoyment to come.

Spring Showers Bring Flooded Gardens

Posted on May 31, 2025June 10, 2025 by Zidack, Heather

By Amelia Martin, UConn Plant Science Graduate Student

Rain gauge showing half an inch of rain on a cloudy day — Photo by H. Zidack, UConn HGEC

You may have noticed the heavy rains and chilly temperatures last week’s nor ’easter brought to Connecticut. Maybe you were one of many who checked their back window to see their gardens had flooded and their plants are looking worse for the wear. If this sounds familiar and you are curious what garden flooding means for your plants and want to know how to protect them- you found the right article!

A flooded garden is not a unique problem, especially during periods of heavy rainfall, but there are some factors that may contribute to the severity of flooding. Having minimal or poor drainage can amplify the problem, especially if planting in garden boxes with closed bottoms. Soil compaction can contribute to flooding if you are planting directly in the ground. Compacted soil can happen if there has been too much tillage, if wheels or machinery have been over the area, or even from excess foot traffic. Lastly, the layout and landscaping of a yard can contribute to flooding as well. If you placed your garden at the bottom of a hill or there are minimal drainage angles surrounding your garden, water may be pooling up faster than it can drain.

To prevent flooding, check your gutters and make sure they are free from debris and directed to a drain or storm barrel. Put down gravel and mulch to help prevent surface flooding. Avoid cutting your grass too short to maintain strong roots which help to absorb water. Maintain healthy soil to allow for the best water absorption. Dig out a shallow drainage channel if you have the space for it. Consider switching to raised beds with drainage rather than in-ground gardens in easily flooded areas. Try adding native plants to your garden. Native plants have deep roots which helps them absorb excess water and prevent runoff. While handling these issues would be preventative measures, let’s talk about what to do if your garden has already flooded.

Assess the drainage situation and take note of where the water is pooling the most. If flooding is unusual in your garden- there may be something blocking the normal drainage route, which may be a quick fix. If not, knowing where water is likely to pool may help in future garden planning, or help you determine where to make improvements.

Stay off your garden beds. If you step on your soil while it is saturated, it will compact it, ruining the soil’s tilth. Instead, if you need to access your garden beds consider putting a wooden board down to walk on to distribute your weight better.

Re-fertilize your plants. Heavy rain can wash away nutrients out of the soil through a process called leaching. Check the forecast to make sure no more extreme weather is immediately approaching before fertilizing- or you may have to do it again.

Add supports to your plants. The wind and rain may have led to plants falling over. Add in some additional supports to get them upright again and give them a better chance for the next time heavy rain comes.

While having a flooded garden may be a bummer, there are some gardening activities that are actually easier to do in saturated soil! Once the rain stops and the ground is still wet, use this time to weed. The soft ground will make weeds especially easy to pull up- just try not to step on the garden beds. After a rain or a flood, re-mulching is always a good idea. The rain might wash away some previously placed mulch, use this as an opportunity to locate any spots barren of mulch and in need of a re-fill. After a couple days when the soil is soft but not sodden, the ground will be the perfect consistency to dig and put stakes.

Lastly, check for any young plants that didn’t survive the water or any seeds that haven’t come up. Take this as an opportunity to plant new seeds, as seeds do better in already moist soil where they have less chance of being displaced when watered.

At the end of the day, while having a flooded garden may not be the best for your plants, it is not the end of the world. There are a handful of preventative measures that can be taken ranging from backyard renovations to quick fixes- it is about finding what works best for you and your garden.

Why Are Seeds Sprouting in My Tomato?!

Posted on May 24, 2025June 2, 2025 by Zidack, Heather

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

A tomato sliced in half with seedlings sprouting up — Seed germination within an overripe tomato. Photo credit: J. Copes.

UConn Home and Garden Education Center alum Carol Quish wrote a short blog post about vivipary in 2014 that, over a decade later, is still one of our most-read pieces. Why are folks still interested to read this post after so much time? Because seeing seed vivipary in a tomato you’re about to eat is just so darn weird. To better discuss and understand vivipary however, we should start with a little refresher on seed biology.

Reflecting back on 4^th period science class with Mr. So-and-so, you’ll recall that producing a seed is both a distribution and reproduction strategy for plants. Generally, a seed is composed of a developing young plant called an embryo and a nutritious tissue to support the embryo called an endosperm, both of which are encapsulated within a hard seed coat. When an embryo is triggered to begin growing and breaks through the seed coat, many people consider this the stage of germination.

A seed will typically be in a state of dormancy while within the fruit and for a period after fruit harvest and dispersal. This strategy of undergoing dormancy is usually advantageous to the seed so it does not germinate and begin growing under adverse conditions, such as the beginning of winter or before being eaten by a hungry critter. A delicate combination of environmental cues and plant hormones maintain – and break – seed dormancy. When temperature, light, moisture, and other environmental conditions are right for that seed, hormones like gibberellin (GA) and abscisic acid (ABA) will shift in balance and germination will occur. Dormancy is typically maintained when levels of ABA are higher than levels of GA, and is broken when levels of GA are higher than levels of ABA.

When germination occurs while the seed is still within or attached to tissue of the parent plant, this is considered vivipary. Appropriately, the word “vivipary” is Latin for “live birth”. Vivipary is an essential strategy for some plants, such as mangrove trees, to increase likelihood of reaching a safe place to grow. For most plants however, vivipary is considered a physiological disorder or otherwise undesirable outcome as it decreases likelihood for successful establishment and growth, post-germination. Some highly-domesticated plants, like tomatoes, peppers, strawberries, wheat, and corn, are more prone to vivipary than others.

Seed germination within an overripe tomato. Photo credit: J. Copes.

While there isn’t uniform consensus on what combination of factors trigger vivipary, promoting high ABA levels in seeds while they’re still in the parent plant will certainly lower the odds. While there is nothing that can be done to change the genetics of the tomato on your counter, you can take steps to minimize the environmental triggers that would decrease ABA levels. Minimizing free moisture, preventing excessively cool temperatures, and drying, consuming, or processing the seed before the fruit bearing it become overripe are important strategies.

For tomatoes specifically, be sure to harvest them before they are fully ripe! Overripe tomatoes are much more likely to experience vivipary. For the same reason, whether buying or growing your own vine-ripened tomatoes, it’s important to consume them quickly. Furthermore, be sure to store your tomatoes at room temperature and not in the fridge. Not only will they be more likely to have a mealy texture when you eat them, but low temperatures may also increase the likelihood of vivipary.

The next time you happen to take a bite of a tomato filled with seeds that have experienced vivipary, don’t fret! The taste and texture may not be what you were expecting, but they’re perfectly harmless. That said, a better destination for a viviparous tomato may be your garden bed rather than your caprese salad! Seeds that have germinated within the fruit will still grow and eventually produce fruit like any other tomato seedling.

If you have questions about growing tomatoes, or any other gardening topic, call the UConn Home & Garden Education Center (toll-free) at (877) 486-6271. You can also email us at ladybug@uconn.edu, visit our website, www.homegarden.cahnr.uconn.edu, or visit your local UConn Cooperative Extension center.

Set Your Lawn Free

Posted on May 18, 2025May 20, 2025 by Zidack, Heather

By Dawn Pettinelli, UConn Home & Garden Education Center

Dandelions growing uncontrolled in a lawn. — Photo by Dawn Pettinelli

For many, the sight of a lush green lawn brings about the desire to cast off one’s shoes and stroll through the sun-warmed grass feeling the soft verdant carpet below. Lawns, or at least grassy areas, are a ubiquitous part of almost every home outside city limits. While admittedly that perfect lawn is a source of curb appeal and homeowner pride, in recent years considerable attention has been given to the ecological and environmental costs of maintaining turf that is the envy of the neighborhood.

Managed turf grass areas, including golf courses and park areas cover about 8 percent (400 square miles) of the land area in Connecticut. That perfect lawn typically requires supplemental irrigation, fertilizer, regular mowing and often pesticide applications. Water could be better used for drinking, other domestic uses and just left in natural systems. Excess nutrients as well as pesticides can be found in ground and surface waters causing both human health as well as ecosystem problems. While some are turning to electric mowers and blowers, gas-powered equipment dependent more on fossil fuels, are most prevalent (at least in my neighborhood) contributing to climate change.

So what is a residential lawn owner to do? The authors of Redesigning the American Lawn were among the first to coin the term “freedom lawn.” So, what is a freedom lawn? Basically, anything that is green is allowed to grow. That would include dandelions, self-heal, violets, bluets, buttercups, clover and wild strawberries to list a few of those so-called “low growing broad-leaved plants”. By my definition, weeds are plants growing in the wrong place, so the plants are weeds no longer when accepted as part of the lawn.

One of the greatest reasons for encouraging a variety of plants to inhabit turf areas is that the world is facing a critical loss of biodiversity. There are significant declines in beneficial insect, native plant and bird populations, along with other living organisms. While that lush green lawn offers aesthetic pleasure to some, it does little to provide habitat or food for creatures other than problematic ones like grubs or chinch bugs.

A mixed grass- herbaceous plant lawn will contain flowering plants for pollinators and other beneficials. Various plant species have varying root systems. Some have deep taproots that break up compacted soil and bring up minerals. Others have more fibrous root systems that are continuously turning over added organic matter to the soil. A variety of plants along with their root exudates and associated microbes can help aggregate the soil, improving air and water passage. Porosity plus water holding capacity can be increased as well as lessening the potential for topsoil erosion. A healthy plant community usually portends a healthy soil.

Leaning into a freedom or pollinator lawn does not mean digging up one’s entire lawn and reseeding it although that is one option. Two seed mixes that I have seen advertised are Flawn and Fleur de Lawn. Both contain a mixture of fescues, microclover and the latter, some other flowering species. Probably greatest success with these seed mixes would be achieved starting with bare soil.

One can start encouraging biodiversity and pollinator plants by discontinuing the use of herbicides and allowing some flowering plants to move in. Often, they can be mowed before they set seed. When reseeding bare spots, use more drought tolerant fescues or native grasses like little bluestem to reduce the need for irrigation, once established. Higher mowing heights up to 3 or 4 inches will encourage deeper rooting of all plants making them more resilient during periods of drought.

Learn about the benefits of some of the low-growing broad-leaved plants that want to call your lawn home. Clovers add nitrogen to the soil reducing the amount of fertilizer necessary. Violets are host plants for the endangered regal fritillary. Dandelion greens are a great source of vitamins A and C. It is true that many of these plants are not native, but neither are the cool season turf grasses normally found in lawns.

In many yards, keeping part of it in lawn is essential for children’s play and sports activities, pet areas and entertaining. Take a tour of your yard and determine where a lawn makes sense and where it might be more appropriate for woody plants, ornamental beds or even a vegetable garden. Steep slopes or perpetually shaded areas may be best for groundcovers. Areas where water frequently collects after heavy rains might be more suitable for a rain garden.

However small, every effort to encourage biodiversity, provide for our beneficials and improve soil health is a step in the right direction. Rethinking your lawn areas might be a good place to start.

For information on lawns or any other gardening topic, call the UConn Home & Garden Education Center (toll-free) at (877) 486-6271 or email us at ladybug@uconn.edu or visit our website, www.homegarden.cahnr.uconn.edu.

Spring Landscape and Garden Issues in 2025

Posted on May 10, 2025May 20, 2025 by Zidack, Heather

By Pamm Cooper, UConn Home & Garden Education Center This spring has been a dramatic one as ornamental trees and shrubs are putting on quite a colorful floral display. Many deciduous ornamentals including redbuds, forsythia, crabapples, fruit trees, quince azaleas and many others were not adversely affected by last summer’s drought and the cold, windy winter and frozen soils that followed. A lesser noticed but significant drama is the negative effect these same environmental conditions had on ornamental and native evergreens.

Rhododendrons and ‘Green Giant’ arborvitae seemed to suffer the most damage followed by cherry laurels and hollies. Last year’s drought conditions that extended into late fall combined with very windy winter conditions and frozen soils were tough for some evergreens. Winter desiccation injury on broadleaved and needled evergreens causes foliage browning when plants cannot take up the water needed to keep foliage healthy. Damage to many rhododendrons and some azaleas could be seen during the winter and is still evident this spring. Buds may provide new leaves by June if branches are still alive.

In contrast, 'Green Giant’ arborvitaes suddenly showed symptoms after warm weather began this spring. This was evident especially in trees on windy sites. Needles are brown or off color and time will tell if they are able to recover. If branch tips are flexible and show new buds, growth may resume. Prune any dead branches that show no signs of recovery.

Large tent like structures with little caterpillars inside them in the crotch of a tree branch. — Eastern Tent Caterpillars in a Black Cherry Tree. Photo by Pamm Cooper

Eastern tent caterpillars have hatched from overwintering egg masses on native black cherries. Silken nests are evident located in crotches of these trees. Caterpillars feed outside the tents at night and hide in them during the day. There is only one generation, and feeding is generally finished by late June. Trees have time to leaf out again to remain healthy during the growing season. Birds like cuckoos and vireos will rip tents apart to feed on the caterpillars.

If you have Oriental lilies, be alert for the lily leaf beetle. This bright red insect can severely defoliate these lilies. Adults overwinter in soil close to the plants they were feeding on the previous season. They appear as soon as lilies begin new growth above the ground. Leaf undersides should be checked for eggs and larvae and crushed when found. Leaves can be treated if needed with a product that larvae will ingest as they feed on the treated leaves. Never spray flowers with any insect control product and always follow directions as written on the product label.

Snowball aphid feeding damage is noticeable on the new leaves of European cranberry bush and snowball viburnums. As the aphids feed on the new leaves and twigs, leaves curl and twigs twist in response to aphid feeding on the sap. Aphids can be found by uncurling the leaves. Treatment is difficult as they are not out in the open where contact control products can reach them. Feeding should end within two months of egg hatch. These aphids overwinter as eggs laid on the branches of host viburnums.

Viburnum leaf beetles, Pyrrhalta viburni, are another significant pest of ornamental and native viburnums. They’re active soon after viburnums leaf out. Damage will be seen as larval populations grow and they skeletonize leaves. Some viburnums may suffer complete defoliation. This pest prefers arrowwood, European cranberry bush or American cranberry bush viburnums. Try switching to resistant varieties such as V. plicatum and Korean spicebush viburnum V. calesii if leaf beetles are a chronic pest.

If anyone has small St John’s wort shrubs or certain weigela cultivars that seem to be dead, wait and see if new growth resumes as it gets warmer and sunnier. The smaller St. Johns’ wort shrubs die back in fall, leaving brown stems with withered fruit. Prune these back almost to the ground as basal growth appears. Some weigela cultivars are just slowly getting started, while others are already full of leaves. Do not give up these plants but wait and see what happens in May.

As always, our UConn Home and Garden Education Center office staff welcomes any questions gardeners may have concerning landscape and garden plants problems. Across the New England region, people are having much the same problems as we are having in Connecticut from the winter weather, but we can hope that plant recovery be swift and complete. Enjoy the growing season and stay alert- scout for pests and other problems before they get out of hand.

A Gardener’s Guide to Planting by Hardiness Zones

Posted on May 3, 2025May 20, 2025 by Zidack, Heather

By Marie Woodward, UConn Home & Garden Education Center

Map of Connecticut USDA Hardiness zones as of 2023. Most zones in the state are either zone 6 or zone 7. — USDA Hardiness Zone Map for Connecticut, 2023

If you are wondering whether that shrub, flower, or tree that you saw in a magazine or catalog will grow well in your garden, using a hardiness zone map is your best bet to ensure success.

A hardiness zone map is a tool that divides a geographical area into distinct zones based on average annual minimum winter temperatures. These maps are used by gardeners and farmers around the world to determine which plants are most likely to thrive in a particular region. Each country has its own hardiness map that correlates to their climate. In the United States, the USDA publishes a hardiness zone map, which covers all fifty states and includes Puerto Rico, Guam, American Samoa, and the U.S. Virgin Islands. It uses climate data collected over many years from weather stations throughout a specific region. Then the data is analyzed to determine average minimum winter temperatures from different areas.

The concept of hardiness zones was first introduced in 1927 by Dr. Alfred Rehder. Rehder worked at Harvard's Arnold Arboretum as a botanical taxonomist. He wanted to address the challenges gardeners and growers faced in selecting plants suited to their local climate. Prior to Rehder’s map, there was no standardized system for categorizing plants based on their ability to survive winter temperatures. His hand-drawn map featured eight hardiness zones and was based on the lowest winter temperatures recorded in various regions across the country. Rehder aimed to provide a practical tool for gardeners and growers. His map made it easier for them to choose plants with the best chances of survival in their region, ultimately contributing to more successful gardens and agricultural endeavors. Rehder’s innovative approach recognized the importance of adapting agricultural practices to local climates. In the 1960s, the USDA adopted and adapted Rehder's concept, creating the first official USDA Plant Hardiness Zone Map.

Since its initial release, the USDA Plant Hardiness Zone Map has been updated several times to reflect changes in climate and the availability of more accurate data. The latest update of the USDA hardiness map was released in November 2023, jointly developed by the USDA's Agricultural Research Service (ARS) and Oregon State University's PRISM Climate Group. This update incorporates data from 1991 to 2020, covering a broader range of weather stations than previous versions. One of the key findings from this update is that the contiguous United States has become approximately 2.5 degrees Fahrenheit warmer on average compared to the previous map. As a result, around half of the country has shifted into the next warmer half zone, while the other half has remained unchanged. The updated map still consists of 13 zones, but now offers more detailed information on temperature ranges within each zone, including 10-degree zones and 5-degree half zones. Connecticut has two hardiness zones each of which is divided into half zones; (6a,6b); (7a,7b), to better reflect the temperatures in the state over the past few decades.

The importance of hardiness zones lies in their ability to help gardeners and farmers choose plants that will thrive in their specific region. By selecting plants appropriate for their zone, growers can reduce the risk of frost damage and increase their chances of a successful growing season. However, due to unexpected temperatures outside the average range, there is no guarantee that a plant won’t suffer but it does reduce the risk of plant damage. In addition to gardeners, researchers use hardiness zones to study the spread of insects and exotic weeds, while the USDA Risk Management Agency uses the map to help determine crop insurance rates for commercial growers.

While the USDA Plant Hardiness Zone Map is an invaluable tool, it is important to note that it is not the only factor gardeners and farmers should consider when selecting plants. Other factors, such as soil type, precipitation, and local microclimates, can also impact plant growth and survival. Gardeners should use the map as a starting point and supplement it with local knowledge and research to make the best plant selections for their specific needs.

The development of the USDA Plant Hardiness Zone Map is a testament to the importance of adapting agricultural practices to local climates. Since its inception nearly a century ago, the map has evolved to reflect changes in climate and incorporate more accurate data. Today, the map remains an essential resource for gardeners and researchers alike, helping them to better understand and navigate the complexities of plant growth in the diverse regions of the United States. Knowing a plant’s hardiness zone when selecting that shrub, tree or flower will help you grow the garden of your dreams.

Celebrate Arbor Day!

Posted on April 26, 2025May 20, 2025 by Zidack, Heather

By Dawn Pettinelli, UConn Home & Garden Education Center

Redbud tree in flower with tiny pink buds. — Photo by Dawn Pettinelli

Arbor Day is celebrated in Connecticut on April 25th. Since it is a day traditionally set aside for the planting of trees, perhaps you might consider adding one to your home landscape. If you haven’t the need for another arboreal specimen, then plan on giving your existing trees a little TLC.

Trees have a lot to offer. They provide us with cool shade on hot summer days, brighten our spring season with lovely blossoms, add color to the fall landscape and winter interest throughout cold, dreary days. Trees provide food, nesting sites and shelter for many animals, especially birds. They help reduce noise pollution, trap particulate air pollutants, and can alter the microclimate surrounding them.

Most importantly, trees supply plenty of oxygen for us to breathe. Each year, an acre of trees produces enough oxygen to keep 18 people alive. They also sequester carbon dioxide. Trees convert atmospheric carbon dioxide into plant matter as they photosynthesize. This has important consequences worldwide. As more and more of our forested land is being cleared, less carbon dioxide can be stored in trees and more is available to increase the atmospheric carbon dioxide levels which, in turn, can contribute to global warming.

While we can’t stop global deforestation, we can make a difference in our own backyards by planting more trees or making sure that the trees already present receive the conditions they need to thrive.

When selecting a tree for your landscape, do consider factors like its ultimate height and spread, susceptibility to insect and disease problems, flowering, fruiting and fall foliage potential, rate of growth and site requirements. Review gardening books, consult with nurserymen and maybe visit an arboretum to view mature specimens.

Trees are purchased either as dormant stock through mail order sources, containerized, or balled-and-burlapped (B & B). Dormant trees generally arrive in the spring or fall and should be soaked for a couple of hours and planted immediately. If you can’t get them in the ground right away, they can be stored in a cool place for a few days out of direct sunlight. Make sure them are kept moist.

Containerized stock can be planted throughout the growing season although cooler spring or fall is best. Hard to transplant species are best purchased this way as there is less disruption to their root system. If potbound, make several vertical cuts about one-quarter inch deep around the root ball before planting.

Purchasing B & B trees is fine for younger specimens, but often larger trees have a good portion of their roots removed in this process. This can lead to poor survival. For greatest success, choose small to medium sized trees.

A tree planted at the proper depth with the crown slightly exposed. The hole is dug twice the width as the original root ball. — Photo by Dawn Pettinelli

Holes for planting only need be as deep as the root system. The key is to make them at least 2 feet wider than the root ball. Especially in heavy or compacted soils, be sure to

loosen as much soil around the planting area as possible so roots can grow freely. The majority of roots are found in the upper 3 feet of soil.

Amendments such as peat moss or fertilizer are not necessary to add to the backfill. However, if the soil pH or phosphorus levels are low, ground limestone and bonemeal can be mixed into the backfill.

Add water to the hole before planting and let it drain. Next, position the root ball. Remove plastic mesh and cords. Burlap can be cut away as much as possible. Fill in the hole about half way. Gently firm the soil around the root ball. Don’t stomp on it or you will compact the soil. Water thoroughly and when the water drains, finish filling the hole. Make a well around the tree with soil and water once more. Apply a 2 to 3 inch layer of mulch keeping it away from the trunk. Newly planted trees need a thorough soaking each week throughout the first growing season either from natural precipitation or from you.

If you have questions about trees or any other gardening topic, call the UCONN Home & Garden Education Center (toll-free) at (877) 486-6271 or email us at ladybug@uconn.edu or visit our website, www.homegarden.cahnr.uconn.edu.

Unbeanlievable: Here’s a Vegetable That Produces All Season Long

Posted on April 19, 2025May 20, 2025 by Zidack, Heather

Abigayle Ward, Soil Science Graduate Student

Beans of the 'Dragon Tongue' variety are. yellow with purple streaks. — Beans like this Dragon Tongue variety can add interest to your vegetable garden! Photo by H. Zidack

Full of fiber, packed with protein, and great to grow, beans have been a staple in the diet of humans for thousands of years. Native edible beans can be found on every continent but Antarctica, although many of the beans we eat today are domesticated varieties that originated in South America, Europe, and Asia. Fabaceae, the bean family, is one of the largest families of plants in the world, with over 20,000 species described. As legumes, beans can convert nitrogen in the atmosphere into nitrogen useable by other plants, making them very useful to integrate into crop rotation for savvy home gardeners who want to save a little money on nitrogen fertilizer. In fact, excessive nitrogen fertilization of legumes can inhibit the natural nitrogen-fixation process, so use only a low-strength nitrogen fertilizer if absolutely necessary. Legumes can even be used as cover crops in the winter to prevent soil erosion and provide a boost to your soil health all winter long. You can direct-seed beans and still get production all season, meaning Connecticut gardeners can get beans in the ground now.

Fava beans (Vicia faba) are grown all around the world, very adaptable to many climates, and are generally very easy to grow. They are cold-tolerant and can be grown all the way down to USDA Hardiness Zone 3. In Connecticut, for the best results, you should plant fava bean seeds in the early spring in a place that gets full sun and doesn’t stay too moist. They will take about three months to begin producing beans but will continue producing throughout the season and into the fall. Some frost-resistant varieties will even survive temperatures below freezing, and since they self-pollinate, bees are not necessary for the production of pods. Fava beans do not require trellises, but some larger varieties may benefit from cages or trellises for additional support. In the summer, pollinators love the flowers, and understandably so – bean flowers not only signal the coming produce but are also eye-catching. Many varieties have white and dark red flowers. Some varieties have pink flowers. Bean pods can be harvested and eaten whole if they are young and tender. It is important to note that some people may have an adverse reaction to consuming fava beans, a metabolic disorder called favism. Favism causes anemia in response to the inhalation of the plant’s pollen or consumption of the beans. Be sure to check with your doctor before trying these beans for the first time.

For “summery” beans that are native to central and south America, you can try planting kidney, cranberry, appaloosa, or navy beans, all in the genus Phaseolus. Perhaps the delight of beans in the Phaseolus genera is their diversity in appearance. Appaloosa beans are especially whimsical, with white, brown, and reddish mottling. They strongly resemble the horse for which they are named. Some of these species behave like pole beans, meaning they will need to be trellised, while others behave like bushes, meaning they should not need to be trellised. The seed packet should indicate whether they will need to be trellised. As with fava beans, be sure to water Phaseolus when the soil seems dry, taking care to avoid watering the leaves. Excessive leaf wetness may increase the likelihood for fungi to grow and cause disease.

No matter what bean you try growing, pests and disease are ever-present. Aphids, bean beetles, and European corn borer are all possible bean pests. Beans are susceptible to diseases like powdery mildew, Fusarium wilt, and bean rust. Selecting disease and pest-resistant varieties will reduce the risk of yield loss. Like most legumes, the ideal soil pH for growing beans is 6-7. Since native Connecticut soil typically has a pH closer to 5.5, be sure to send a soil sample to the UConn Soil and Nutrient Analysis Lab to test the pH (and nutrients!) of your soil before planting to ensure you get accurate recommendations for any amendments your garden may need to allow beans to thrive!

Home and Garden Education Center