“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
Help us improve the Maryland Grows Blog! Please complete our brief survey to give us your feedback and let us know about your interests.
Winter is a good season to plan for spring. In today’s post, we want to tell you a bit about a type of planting that one can consider. This planting will boost the stability of our green spaces, turning them into havens of biodiversity. Let’s talk about floral supplementation and floral supplements.
Example of a floral supplementation in the form of a flower strip (e.g., “pollinator strip”) in a Mid-Atlantic agroecosystem. Photo: K. Evans.
What are floral supplements?
Floral supplements are semi-natural habitats that are added to green spaces and are designed to concentrate a large amount of plant resources into a small area. By including a mixture of herbaceous or woody flowering plant species, floral supplements provide food and habitat to local wildlife. This increase in floral resources correlates to local increases in the number of insect and other animal species and their abundance, which results in the improvement of ecosystem services in the area. Common examples include pollination, pest suppression, nutrient (re)cycling, soil conservation, and improvements in water provision and quality.
Hairstreak butterfly collecting nectar (left); a leafcutter bee using yellow bits of partridge pea flowers to line the interior of their nest (center); early spring andrenid bee returning to her underground nest in May. Photos: K. Evans.
While supplements formed of mainly herbaceous flowering plants offer great nectar, pollen, and nesting resources to insects that act as pollinators and pest control agents, other plants can also be used to create floral supplements. In particular, woody plants and shrubs can provide valuable food and cover for various songbirds and small mammals. The benefits of floral supplementation go beyond supporting insects, birds, and mammals. In fact, these plant additions also have been shown to assist with weed suppression and to reduce soil erosion, while permanent woody plantings (e.g., hedgerows) can also serve as windbreaks.
Hedgerows are coming into leaf along a road in the spring. Photo: McEnnerney/Alamy.
Nowadays, floral supplements can be found nearly everywhere, from home gardens to roadsides, and croplands to city greenspaces, and are commonly referred to as “pollinator strips” or “conservation strips”. Generally, floral supplements are primarily implemented as a conservation initiative to support wildlife and arthropod biodiversity, particularly in floristically impoverished areas such as agricultural monocultures and urban environments.
The origin of floral supplementation
The concept of floral supplementation has roots in agriculture. For example, the use of companion plantings and flowering margins in and around crops has been long known to enhance biological control by boosting natural enemies of crop pests, such as predatory bugs and beetles, and parasitic wasps. In this respect, the addition of these plants to the agroecosystem has been recognized as a strategy to improve pest control with lower pesticide inputs.
Spiders (left) are important natural enemies of pests, such as this crab spider lurking on a black-eyed Susan. Floral supplementation also supports the presence of other pest control agents, such as this samurai wasp, Trissolcus japonicus, parasitizing brown marmorated stink bug eggs. Photos: K. Evans; S. Athanas.
Today, the concept has expanded in conjunction with aesthetic and conservation initiatives. For example, the Beautification Act of 1965 encouraged roadside wildflower plantings, and actions such as establishing pollinator gardens and defining no-mow months increase floral resources for pollinators. The USDA also offers conservation programs for monarchs and other pollinators by encouraging farmers and ranchers to plant pollinator-friendly wildflowers, shrubs, and trees (https://www.nrcs.usda.gov/).
No Mow initiatives promote not mowing the lawn to allow early spring flowers to grow and bloom, thus providing food for early spring insects.
How to start with floral supplements?
Although there is not a hard definition for what constitutes a floral supplement, guidelines have been proposed by government and conservation societies including the Xerces Society and the USDA. What species to plant ultimately depends on the location and purpose of the supplement. For example, recommended species to plant for upland or grassland habitats will be different than those for wetter habitats. Generally, however, regionally native or naturalized species are often recommended to sustain more native animal diversity than exotic species. In fact, because most ornamental plants used for aesthetic purposes are often non-native, they tend to offer unsuitable or no resources to the local animal communities. Further, even among native species, regional varieties (i.e., local ecotypes) are often preferred because they are better adapted to the local climates, growing conditions, and living communities.
Flower plantings can sometimes support specific pollinators, such as monarch butterflies. Examples of this are roadside and field margin milkweed plantings (left) and the participation of cities in the Monarch City Certification Program. Photo: Bill Hubick, Maryland Biodiversity Project.
Another aspect to consider when starting or creating floral supplements is the diversity of plants used. In fact, diversity is a common theme for floral supplements: one seeks to obtain a high diversity in flower color, flower shape, and bloom times. For example, the best supplements contain a mixture of annuals, perennials, and woody plants that bloom at different times throughout the growing season to ensure that floral resources will be sustained over time. Further, including flowers with diverse shapes, colors, and sizes facilitates access to nectar and pollen for arthropods with different mouth and body shapes.
Although one can try to do it by oneself, designing a floral supplement can be tedious and sometimes overwhelming. Luckily, federal agencies, seed companies, and local nurseries have mixes available for certain habitat types and regions, that one can order directly.
By Katy Ciola Evans, Ph.D. student in the Espíndola Lab, University of Maryland Department of Entomology. View her website to learn more about her research.
Let’s talk more about seed-starting! Last month I posted about how to get your house ready for a seed-starting project: picking a space to use, deciding where to hang your lights, and choosing the lights. I also wrote a bit about what containers to use, but in this post I’ll give you more detail, and also talk about what “soil” (actually soilless mix or growing medium) to use.
Seedlings growing in recycled plastic egg cartons
Containers
There are basically two parts to a seed-starting apparatus: the tray, and the pot or cell. Here’s some information about each.
Trays
The purpose of a tray is to contain or capture water. You need a tray unless you want a big mess. It should not have holes in it.
Trays can be any size larger than a pot. Standard industry size is 10”x20”. You can also use takeout containers (or any food-grade plastic), old baking pans, or anything else that suits your needs.
Most trays are plastic (aside from the baking pans). Standard trays full of pots sometimes crack when lugged around and left outside, so consider doubling them up or buying the heavy-duty ones.
Pots
The purpose of a pot is to contain the medium in which a plant grows. Pots are separate entities, and cells are connected pots. You can buy cell sets that fit standard trays. You can also save the cells and pots that you bought plants in. Yogurt cups and the like are great to recycle into pots, or you can use plastic drinking cups. Plastic egg cartons can substitute for the smallest size of cell set.
Pots must have drainage. If water can’t drain out of a pot, plant roots can rot. Commercial pots will have holes already; if you use recycled items, punch holes with a nail or a knife or whatever you have (the shape doesn’t matter, but make several).
If you don’t want to buy plastic, you can spend more and get pots or cell sets made of silicone or ceramic. These should last many, many years and be easy to clean.
Any pot of the above types needs to be cleaned before each use. A 10% bleach solution is effective at killing pathogens that may lurk in bits of leftover soil. You can instead use dish soap if you’re pretty sure the pots haven’t been exposed to plant diseases.
The other type of pot/cell set on the market is the plantable kind. These are made of compressed peat, coir, or processed manure (they don’t smell!). They are filled with growing medium just like a plastic pot, but the whole thing can be put in the ground when the plant is ready.
Make very sure to keep plantable pots moist at all times, starting by soaking them before using and continuing until planting time. Remove any dry rims and some of the bottom before planting. Dryness can prevent proper plant growth.
Plantable pellets (made of peat or coir) expand when moistened and have a hole to put a seed into. They can also be planted whole, or transplanted into a bigger pot.
How big a pot to choose? It depends on how many times you want to “up-pot” or transplant into a larger container. If you start with small cells, the seedlings will have to be moved into larger pots, maybe more than once, but you are saving space, soil, and water in the early stages. (Just be sure you have room under lights for your expanded plant kingdom!) Planting directly into larger pots means you won’t have to up-pot, but you may waste time, space and materials if seeds don’t germinate, and it’s harder to keep the soil watered.
Plastic cell tray (black), silicone cell set (orange), peat pots (small), pots made of cow manure (large), compressed coir pot (single)
Growing Medium
It’s recommended to start seeds in a soilless mix consisting mostly of peat or some other organic material. There are lots of choices available on the market, and if you’re ambitious, you can mix your own. Read HGIC’s page on the topic and check out Jon Traunfeld’s post on peat-free mixes.
For smaller seeds, you want to find a finer-cut mix (lightweight and fluffy, not heavy like sand); larger seeds can tolerate a mix with larger particles. The name on the package may not mean much: “seed-starting mixes” can be quite rough in texture, and “potting mixes” vary a lot too. Look at the ingredients and try to avoid anything with “forest products,” which seems to mean little bits of wood.
Seeds themselves contain nutrients to get a baby plant started, so germination and early growth don’t require fertilizer in the growing medium. If you’re going to be growing the plant in that medium for more than a week or so, though, the mix should have fertilizer or compost in it. Alternatively, you can add fertilizer when you water. Or you can add your own compost to your growing mix, as long as it’s finished and screened, but don’t use garden soil, which may contain pathogens or weed seeds.
Next month I’ll take you through choosing what seeds to start, how to get them to germinate, and how to care for your young seedlings.
In the meanwhile, here are some more items you might consider acquiring into addition to the seeds themselves:
A seedling heat mat, especially if you are planning to start seeds for summer vegetables and flowers. Seeds need warmth to germinate, and sometimes a bit of extra heat helps.
A sprayer (for getting the soil surface wet without washing tiny seeds away) and a watering can with a narrow spout.
Clear plastic domes that fit over your trays. These help keep moisture in when seeds are germinating and plants getting started. You can buy them or improvise them out of recycled plastic clamshells (like for salad mixes).
Labels!!!
I’ll tell you more about all these helpful items next month.
By Erica Smith, Montgomery County Master Gardener. Read more posts by Erica.
