2024 is Grow It Eat It’s Year of Heirloom Tomatoes! We’re going to have lots of resources available soon to help you celebrate these delicious and historic vegetables (botanically fruits), and we hope you’ll participate by planting a few in your garden. I thought, as an enthusiastic heirloom tomato gardener myself, I’d take a moment to make some introductions.
First of all, what is an heirloom tomato? Well, I think we know what a tomato is; what puts it in the same category as Grandma’s topaz necklace or Grandpa’s grandfather clock? They’re all handed down through the generations. “Heirloom” doesn’t have any single definition when it comes to vegetables. It can mean that the origin of a particular variety goes back more than 100 years, or 75 years, or that it was first grown before a certain date. Many people use World War II as a marker, because the growth of hybrid crops boomed in the subsequent decades, and a lot of older varieties disappeared from seed catalogs. Varieties grown in a particular community or culture, or through several generations in a particular family, are also considered heirlooms. Family names are often part of a variety name, which makes you feel like a cousin when you grow them!
You can hear them cackling. The winter weeds are laughing because they’re sure you haven’t noticed them.
They think you’ll just stroll by and not notice them lurking in your lawn and beds, sneaking and snaking their way across your landscape.
The loudest howls come from the mighty few that have the audacity to be unfurling a few flowers or a smattering of seedheads.
Think this is fiction? Nope. Weeds classified as winter annuals are having a field day out there and they spell big headaches for our springtime gardens.
Common chickweed (Stellaria media), a winter annual weed that vexes many local gardeners. Photo: K. Mathias, University of Maryland
Winter annuals germinate in the fall to kick-start their growing. Cold weather slows them down some, but in milder winters they do some serious expanding to vex us in the spring.
Don’t let them. Get out there and show them who’s the boss.
I got a call from a client whose lawn was being eaten by henbit(Lamium amplexicaule), a notorious winter annual. Its scalloped leaves and purple flowers make us think it belongs, but it doesn’t. Be merciless.
Henbit’s charming name belies an aggressive habit. Photo: UME – Home & Garden Information Center
The yellow flowers of common groundsel(Senecio vulgaris) are popping up around our offices. It’s another one that needs to go.
Common chickweed looks innocent enough with its tiny white star-shaped flowers. Don’t be fooled.
Chickweed, purple deadnettle (Lamiumpurpureum), and hairy bittercress (Cardaminehirsuta) have all done well in the last few years. While their names are lovely, they have terrible habits.
Like most winter annuals, hairy bittercress makes abundant seeds. Photo: Betty Marose
So how do you banish these beasts? Knowledge is power. Scout your gardens and look for plants that are out of place and looking particularly vigorous. They might be winter annuals.
Next, use a good resource to identify them. One is our Home & Garden Information Center website which has photos and management tips.
You also can send me photos for identification and advice on cultural, mechanical, and chemical controls.
Cultural controls focus on how you manage your landscape. Many lawn weeds can be controlled by beefing up your lawn to stave off interlopers.
Other preventive cultural controls include planting tightly, mulching, and using groundcovers or cover crops.
Mechanical controls are physical controls such as pulling, digging, or mowing to keep weeds from making seeds.
It’s particularly important to control winter annuals before they set seed. Annuals make up for the fact that they only live one year by making ridiculously large amounts of seeds.
Always, always follow the directions on the product label. More is not better and can cause harm.
Break the cycle of winter annual weeds in your landscape. Use all the tools in a smart gardener’s toolbox: prevention, identification, and informed controls.
By Annette Cormany, Principal Agent Associate and Master Gardener Coordinator, Washington County, University of Maryland Extension.
As we mentioned in previous posts, when we think about pollinators, we tend to think of butterflies and bees, but rarely about the super important hoverflies or other groups of organisms. In today’s post, I want to tell you about another of those little-known pollinator groups; let’s talk about beetles that act as pollinators!
Beetles: “hard-shelled” pollinators
From a taxonomic perspective, beetles are a group of insects that belong to the Order Coleoptera. Among other important characteristics, they are recognized by their extremely well-protected body, in particular by structures called “elytra”, which provide a very hard cover to their wings (the wings are placed under the elytra). Generally, beetles have mouth parts that are adapted to chewing, which means that they have large mandibles that allow them to break their food. You may be wondering why I am talking about these structures in a pollination post… well, as for all pollinators, the shape and function of a pollinator define what they do (and don’t do). Let’s see how this affects our pollinating beetles.
Beetles are common flower visitors, with some of them being very effective pollinators. Because of their very well-protected bodies (see elytra covering the “back” of this beetle), they often spend a lot of time on flowers, where they feed on pollen, nectar, and floral parts. In this picture, we can see a cetoin scarab beetle with prominent elytra and a very hairy body that helps them transport pollen grains between flowers. Photo: C. J. Sharp (CC).
In the case of beetles, the fact that they are well protected by those elytra makes them more “confident.” That “hard shell” provides a great deal of protection against predation by other arthropods, which in turn makes them generally more “chill” in their visits to flowers. Unlike butterflies, bees, or hoverflies, beetles tend to move little within and between flowers, taking all their time to get the resources they need from them. For this reason, they are often considered as more generalist and inconsistent pollinators than their less-protected counterparts.
The shape of their mouths and their feeding habits also affect their efficiency as pollinators. In fact, beetle visits to flowers tend to be relatively destructive because they are attracted to them by their floral tissues, including in some cases pollen and the ovaries! In this respect, beetles tend to visit flowers to feed on them, which in some cases can lead to floral destruction. So, given this, are beetles good pollinators or just flower herbivores?
Beetles as pollinators
Among all the many different groups of beetles, some of them are considered to be particularly good pollinators. Specifically, these belong to the beetle families known as soldier (family Cantharidae) and longhorn (family Cerambycidae) beetles, families that depend on floral resources for their survival at least at one stage of their development. Other families such as scarabs can also be strongly associated with flowers for their survival. In all these groups, the beetles in question have clear adaptations that make them good agents of pollen transfer. For example, we observe different parts of their bodies covered with abundant hairs. This improves pollen transport and thus increases their ability to effectively cross-pollinate the flowers they visit.
Beetles that are good at transporting pollen have hairier bodies that can carry pollen grains, like this cantharid beetle that got its face covered in pollen while visiting these flowers. Note the yellow “powder” – pollen – that covers part of the beetle body and take a look at the large mandibles the beetle uses to feed on floral parts. Photo: J. Tann (CC).
Further, although these beetles tend to still feed on floral parts, they are usually much less destructive than their more generalist cousins. They often feed on specific flower parts (instead of on all the floral sections), leaving the central reproductive structures (e.g., the ovaries) intact, and thus allowing plant reproduction. These beetles are also often more specialized in their floral choices, preferring a small range of plant groups (usually one or a few species within the same plant genus), and moving more readily between flowers. Combined, all of this means these beetles can not only carry a lot of pollen (they are hairy) but also move it from flower to flower more effectively and do not destroy completely the flowers they visit.
A cool beetle pollination example
Beetle pollination is a very understudied topic in temperate regions such as Maryland, and we are still learning a lot about it. It is thus not surprising that the number of examples from our region is not super high. Let’s talk about one of them that happens to be relatively well-studied elsewhere but that also occurs in North America.
Beetles are considered some of the most important pollinators of species of the genus Magnolia. Here, a long-horned (Cerambycid) beetle on a Magnolia grandiflora flower. Photo: D. Hill (CC).
An example of beetle pollination of native plants that are also present in our region is that of Magnolia flowers. Although most of our knowledge on the pollination of this plant genus comes from studies done on species outside of North America, there are a couple of reports of floral visitors in several of our local species. From elsewhere, we know that these trees display flowers that appear to be particularly attractive to beetles: they are white, easily accessible, offer a lot of pollen, are fragrant, and in some cases even produce heat! In many of these species, the flowers appear to attract scarab beetles, which, once landed on the flowers, feed on the petals, mate, and then actively move between flowers and cross-pollinate. In North America, some studies like this one and this other one (in PDF) have found a wide variety of beetles attracted to our native species. Many of these beetles are very small and visit Magnolia flowers to feed on them, mate, and spend the night protected within the flowers.
By Anahí Espíndola, Assistant Professor, Department of Entomology, University of Maryland, College Park. See more posts by Anahí.
Anahí also writes an Extension Blog in Spanish! Check it out here, extensionesp.umd.edu, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!
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Plastic tree tie embedded in a crapemyrtle trunk because it was not removed promptly. Photo: Miri Talabac, University of Maryland Extension
Q: There’s a crapemyrtle in our new yard that has a plastic cable tying it to a stake that has become stuck in the wood. Should I cut it out so the trunk can heal?
A: No, that will cause more damage and potentially lead to even more wood decay and crown dieback. All you can do is carefully cut off the excess outside the bark (don’t worry about making it flush; you don’t want to cut into live wood). Gardeners and landscapers should monitor any trees they stake for indications a trunk tie is abrading, cutting into, or being enveloped by the bark. Most trees don’t need staking, and even when they benefit from it, removal of the stakes and ties is recommended after six to twelve months of use. No tie or trunk brace should be so tight that the trunk cannot sway a bit in the wind.
It’s hard to predict how much of an impact the damage you found will have on the branches that particular trunk feeds. Fortunately, the tie in your case did not encircle the trunk, just brace one side of it; I’ve seen several instances where encircling ties become embedded and essentially strangle and kill the entire top of the tree (Leyland cypress and Arborvitae being common victims).
Tree and shrub wood expands outwards as it grows, increasing in diameter as each ring of new wood growth is formed yearly. Although an imperfect comparison, there are parallels to how coral reef colonies grow – over time, the innermost “skeleton” is no longer alive, though it provides support, and the outer shell of tissues is living and actively growing, save for the bark itself. (You can think of bark a bit like nails on a person or pet…it’s produced by live tissue, but the material itself is not alive.)
If the tie extensively obstructs the cambium that lies under the bark (the live tissues moving water, sugars, and nutrients around the tree), one or more major branches above it may die back in the coming years, for which there is no treatment. In some cases, the obstruction just becomes buried under years of growth, hiding it from view. (This is a hazardous situation if the tie or obstructing material were metal, and the tree was removed and chipped up one day.)
Trees can’t heal quite the way animals do, but with luck, this damage will remain minor and not cause significant dieback. If it does, though, you’ll have to cut down that trunk. Since crapemyrtle tends to sucker readily, new growth can take its place if you let a sucker mature into another trunk.
By Miri Talabac, Horticulturist, University of Maryland Extension Home & Garden Information Center. Miri writes the Garden Q&A for The Baltimore Sun and Washington Gardener Magazine. Read more by Miri.
Have a plant or insect question? The University of Maryland Extension has answers! Send your questions and photos to Ask Extension. Our horticulturists are available to answer your questions online, year-round.
It’s February, so really time to think about starting plants from seed, if not necessarily time to actually start them. (If you are itching to get going, I wrote a post a while back about which seeds to sow in February. Hint: not tomatoes.) Let’s continue with the guide, which I hope you’re finding a practical help to this complicated subject. (Parts One and Two also available.)
Choosing Seeds
If you have not already impulsively ordered a bunch of seeds without concern for whether they’re the easiest ones to grow (in which case you are a person after my own heart), now is a good time to go shopping. In most cases these days that means shopping online. You can certainly buy seeds at garden centers and even supermarkets, though they may not be on display this early, but you get a much better selection by visiting the full catalog of a seed company website.
I’ve written a post about choosing a seed catalog to order from, so won’t repeat that information here. If you are confused by the jargon used in seed catalogs, Jon Traunfeld explains it in this post.
But which plants are best for novice seed-starters to grow from seed? First of all, you shouldn’t always let ease dictate what you choose to grow. If you like a vegetable (or a flower) and want to grow it, you may be willing to take on the challenges involved. Some seeds are more cooperative than others, however. Of the many veggies that are best started indoors, here are a few I recommend for beginners:
“Anyone who thinks that gardening begins in the spring and ends in the fall is missing the best part of the whole year. For gardening begins in January with the dream.”
– Josephine Nuese
January is the month of garden dreams. The winter pause gives us time to think, to plan, to ponder. How can we make our gardens better, more productive, more beautiful and sustainable, more the gardens of our dreams?
A garden is never done. This idea eludes new gardeners. But those of us with a few gardening years behind us realize that we are always pursuing an ideal.
Misty memories recall our grandmother’s garden. Trips to public gardens inspire. Friends’ gardens spark ideas. And so our gardens evolve.
These changes are part of the joy of gardening. As gardeners, we are always learning and adapting.
When we bring into our garden an idea that we’ve seen elsewhere, it isn’t stealing. It’s imitation, the ultimate flattery. Soon our garden becomes a memory garden, a reflection of special people and places.
So as the snow falls, the wind howls, the rain whips our windows, we dream of better gardens.
We flip through photos of gardens we’ve visited. Ah, yes. There is that arbor we fancied for the perennial bed. We must have that peony. And that birdbath would be perfect in that corner.
That jars a memory of a berry-laden bush in a friend’s yard that a mockingbird favored. We make the call, get the name, and add it to our wish list for spring nursery visits.
Seed catalogs tumble from our mailboxes. Ripe with ideas, they make our dreams flavorful as we salivate over heirloom tomatoes, Thai basil, and hot peppers. We rush to put together an order before the best varieties sell out.
A crimson flash catches our eye as a cardinal glides by the window. An arc of ornamental grasses would enliven that view, wouldn’t it? Grasses sway in our minds as we add them to our list.
Seeing a copy of Garden Revolution on our bookshelf, we are reminded of our New Year’s resolution to be more sustainable.
We remember from a garden talk the suggestion to add seating to our gardens – places to rest, relax, and enjoy the lovely views we create. Our wish list grows to include a wooden garden bench.
Winter is the time to dream of a garden that feeds body and soul, that delivers a bountiful harvest of food and beauty. So pour a cup of tea, wrap yourself in an afghan, and dream on.
By Annette Cormany, Principal Agent Associate and Master Gardener Coordinator, Washington County, University of Maryland Extension.
Tree planting efforts are picking up as Maryland’s 5 Million Trees Initiative moves forward in 2024. Getting these trees – any landscape trees – off to a good start at planting time and through their first few years of establishment is important for their long-term growth and benefits to the environment.
At Ask Extension, we often receive photos of newly planted trees and older specimens with signs and symptoms of trouble. One of the things we do in our diagnostic process is look to see if there is a “root cause.” Is a girdling root present at the base of the tree trunk? Is the tree planted too deeply? Can we see a root flare? Today I want to bring these questions to the surface and explain why an exposed root flare can help prevent the formation of girding roots and why it matters for tree health and pest management.
A beech tree with normal, healthy root flare. Photo: Miri Talabac, University of Maryland Extension (UME)
What is a root flare?
The root flare is the area at the base of a tree trunk where the topmost roots emerge outward. This area is sometimes referred to as the trunk flare or root crown. In many species of trees, the trunk widens and curves outward (“flares”) like the base of a wine glass. This is illustrated nicely in this brief video by the University of Maryland Arboretum and Botanical Garden’s Outreach Coordinator, Meg Smolinkski.
What is the root flare of a tree?
When thinking about the trunk and root system of a tree, it is important to keep in mind: Roots need to be in the soil to get a steady supply of moisture and nutrients. The trunk (stem) portion should be out of the ground where exposure and good airflow help to keep the bark dry.
In our landscapes, we have many trees that are planted too deeply and the root flare is not visible at all. The trunks go straight into the ground like telephone poles. This can result in lower bark rotting, reduced oxygen supply to the roots, disease and pest problems, and girdling roots.
We have an epidemic of planting trees too deeply
At the University of Maryland Extension Advanced IPM Conference for the commercial horticulture industry last month, Jacob Hendee, an arborist for the Smithsonian Institution Gardens, talked about how common it is nowadays to see trees planted too deeply. Burying the root flare has reached “epidemic” proportions in our landscapes, he noted – and it is killing trees.
The main problem he addressed in his talk was that buried root flares can set the stage for stem girdling roots to develop unnoticed. Stem girdling roots (SGRs) grow around the tree’s base, rather than pointing outward away from the trunk as normal roots should. As girdling roots grow and enlarge, they compress the water- and nutrient-conducting tissues in the tree. This interrupts normal plant functions and can lead to symptoms such as leaf yellowing (chlorosis), smaller-than-normal leaves, leaf scorch (browning), branch tip dieback, and bark cracking. SGRs can and do result in overall tree decline and eventual failure.
An example of girdling roots. Photo: M. Talabac, UME
Looking at a cross-section of a tree trunk, the light-colored portion is the water-conducting sapwood (xylem). Source: Jacob Hendee, Smithsonian Gardens
When a stem girdling root forms around the trunk of a tree (represented in orange in the diagrams), it compresses and kills the water-conductive sapwood, which can result eventually in a dead tree.Source: Jacob Hendee, Smithsonian Gardens
Trees under moisture stress due to stem girdling roots become more susceptible to pests and diseases.Scale insects are significant pests of some landscape trees, as are some types of beetles and other insects. If a tree develops a pest issue, the pest may be secondary to the problem that made the tree vulnerable to the pest in the first place – stress.
Hendee emphasized that maintaining a visible root flare and preventing SGRs are practices of Integrated Pest Management (IPM). IPM involves using physical, cultural (plant care), and biological methods to manage pests and diseases, leaving chemical pesticides as a last resort. In the example of tree care, correct planting and monitoring to prevent stem girdling roots are key steps to preventing tree stress. Instead of thinking about killing secondary pests that show up on trees, think about how to prevent stressful growing conditions from the beginning and during the life of a tree. Trees with minimal stress are more resilient to insect pests and less likely to be overwhelmed by them or need intervention to recover.
How do stem girdling roots get started?
Hendee noted that plant care practices, both before planting (at the nursery), during planting, and afterward (over-mulching) contribute to this problem.
1. Many trees are grown too deeply in the nursery. Girdling roots can start to form inside nursery pots when the roots hit the container and start circling. This issue can worsen when young trees are moved into larger containers as they grow (such as saplings being transplanted into a bigger pot as they mature) and their roots are not loosened or pruned to correct deformities. Larger trees are sometimes planted too deeply in the nursery field and come to the customer in “ball and burlap” form with the root flare already covered in soil.
2. Many trees are planted too deeply at the time of installation. If the planting hole is dug too deeply, the root flare gets buried when the soil is filled back in, and often then further covered with mulch. In that situation, stem girdling roots can develop and worsen undetected.
3. Tree flares are often buried deeply in mulch. Too often we see huge piles of mulch – sometimes one foot high or more “mulch volcanoes” – around trees. This will keep the bark moist and can encourage new roots to sprout from the trunk above the main supporting roots (the flare). Those adventitious roots will grow upward for oxygen and may begin to girdle the flare and trunk. They will also be more vulnerable to moisture stress since the mulch does not retain water in the same way soil does. There is absolutely no horticultural basis for putting a big mound of mulch around a tree like this!
An example of incorrect mulching. Photo: Dr. David L. Clement, UME
Here fresh mulch was incorrectly placed on top of a girdling root and up against a tree trunk. Photo: C. Carignan, UME
What can you do? “Free the Flare”
1. Check the roots at planting time. If you purchase a container-grown tree, ensure it is free of circling roots inside of the pot. If you do find roots that are circling the root ball, cut through those roots with a pruner or other sharp tool. Set the roots in the planting hole so that they are pointing in an outward direction.
Prevent girdling roots when planting a container-grown tree
2. Keep the top of the root flare visible. Root flares should be above the soil line. Plant so the root flare is 2 to 4 inches above grade. When purchasing a container-grown or burlapped tree, you may need to wash away some of the soil to see where the root flare begins. If a landscaper is installing a tree for you, make sure they set the tree at the correct depth.
A hose was used to wash away the soil from a container-grown tree, revealing the top of the root flare. The difference in the lower bark color (on the trunk) indicates that the plant was several inches too deep in its container. Photo: M. Talabac
When a root flare is visibly present, it can help deflect any stem girdling roots that begin to grow, forcing them away from the trunk. It also makes it easier to see where girdling roots begin to form. Monitor the root flare area of your tree(s) regularly and cut through any circling roots that begin to grow. It is easier to cut wayward roots when they are small. The process of locating and remediating stem girdling roots on older trees can be very expensive.
Also note that some species of trees are more prone to developing girdling roots (e.g., maples), and sometimes girdling roots develop below the soil surface where they are not easily detectable except by above-ground clues. If you see symptoms of water stress in the canopy of an otherwise sufficiently-irrigated tree (e.g. leaf scorch, smaller-than-normal leaves), consult with a certified arborist for a tree assessment.
3. Don’t overdo it with the mulch! Keep a mulch-free buffer zone around the root flare. Hendee suggested leaving a 3 to 12-inch area bare around the base of the tree. Think of it as a donut hole: mulch should be laid down in the shape of a wide, shallow donut rather than a big heaping mound. The total depth of the mulch should be only about 2 to 4 inches.
Mulch applied correctly. 1 Free root flare, 2. Mulch-free buffer around the root flare, 3. 2 to 4 inches mulch depth, 4. Broad mulch width. Infographic by Smithsonian Gardens
For further exploration of these topics and correct tree-planting procedures, I recommend the following resources:
By Christa Carignan, Certified Professional Horticulturist & Coordinator, University of Maryland Extension Home and Garden Information Center. Read more posts by Christa.
Illustrations used with permission from Jacob Hendee, Smithsonian Gardens
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