Annually, our State Forest Tree Nursery grows millions of native trees and shrubs for conservation, reforestation, and residential projects that are sold as bare-root seedlings. Bare-root plants are also commonly sold by online retailers, and available at local plant swaps. Why bare-root seedlings? Some key advantages are that they are less costly to store and transport, quicker to plant, and less likely to spread pests and diseases. Cons are the root systems need to be kept moist and they need to be planted within a short timeframe.
This week, Francis Smith from MD DNR’s State Forest Service helped us plant 140 native bare-root shrubs- (red chokeberry (Aronia arbutifolia), black chokeberry (Aronia melanocarpa), and Canadian serviceberry (Amelanchier canadensis) at the Central Maryland Research and Education Center in Clarksville. He shared best practices on how to plant and care for bare-root seedlings.
Storage tips: plant your seedlings within 7 days. Until then, keep the seedlings moist, cool, and dark. A garage or cooler maintained at 33-50 degrees Fahrenheit is ideal. A packing or moisture gel such as Terra-Sorb is a convenient way to keep roots hydrated (Fig. 1). Submerging them in water seems intuitive, but is NOT recommended. Also, refrigerators are NOT recommended because they’ve dehumidifying properties that can damage seedlings.
Fig. 1: Roots of a Canadian serviceberry seedling stored with a moisture gel
Field Handling & Planting Tips: keep seedlings in a cool, shaded area. Avoid pruning top growth if possible. Francis did recommend pruning roots that were longer than 3-5 inches (Figs. 2 & 3), so the roots will fit into the wedge and to encourage new root growth. You can use a shovel or a handy tool called a planting bar or a dibble bar (Fig 4.). Check out Francis’ 2-minute video ‘How to Plant a Bare Root Seedling’ for instructions on how to create a straight wedge, position roots in the wedge (straight down vs J-roots), and tamping the soil down to avoid air pockets. If mulching, be sure to leave a ring of bare soil around the seedling (Fig. 5), as some materials absorb nitrogen, depriving the seedling of nutrients.
Fig. 2: Seedling pre-trimFig. 3: Seedling post-trimFig. 4: Planting bar/dibble barFig. 5: Bare earth ring around seedling
The beauty of working with bare-root seedlings is that they’re economical, quick to plant, and create minimal soil disturbance, decreasing weed seed brought to the surface. If you have a difficult site or have a large project in mind, this might be an especially good option for you. For more information, check out MD DNR’s ‘Bare Root Seedling Planting Guide.’
By Lisa Kuder, Native Plants and Landscapes Specialist, University of Maryland Extension. See more posts by Lisa.
Confession time. I’m a career tightwad. I love saving money. I want quality but I don’t want to pay more for it. Gardening is no exception. Fortunately, there are plenty of ways to save on everything from plants to tools.
First, know that gardeners are generous souls. We love to share seeds, cuttings, divisions and more. So tap your gardening friends to see what you can snag or swap. Look for seed swaps. National Seed Swap Day is in late January. Many organizations including Master Gardener groups organize swaps. But you can find seed swaps throughout the year or organize your own.
Swap and share seeds with friends and neighbors. Photo credit: Erica Smith
Make your own compost. Use free pallets, chicken wire or recycled wood to make the frame. Toss in leaves, grass, straw, food scraps and other organic materials, all free. Grow plants you can divide in a few years to get free plants to use or share. Most perennials and bulbs should be divided every three years. Growing plants from seeds can save money, too. I direct seed some plants like basil and squash. Others nurture seedlings under grow lights which involves an initial investment but saves a good bit of money in the long run.
Make low-cost compost bins from re-purposed pallets. Photo credit: Jon Traunfeld
Potting soil prices have gone up, up, up so everyone’s looking for deals. Save by buying broken bags at a discount, hitting end-of-the-season sales or sharing the cost of a big bale with friends. Tap the buddy system to save in other ways. Split a flat of flowers or the cost of rented equipment like an lawn aerator.
Use what you have. Make pea stakes – trellises for the vines to climb – from tree and shrub trimmings. Turn chopped leaves and untreated grass trimmings into mulch. Become a rabid recycler. Use plastic salad boxes as seed starting trays. Convert old dresser drawers into grow boxes for salad greens. Repurpose everyday containers to grow vegetables. Five-gallon buckets and crates can become affordable small-space gardens.
Pepper plants growing in self-watering containers made from re-purposed food-grade buckets. Photo credit: Kent Phillips
Save seeds. Unless you have a hybrid plant that won’t come back true to type, save seeds to use next year. Seeds even a few years old will often deliver good germination. Market your muscle. Some CSAs will give you a share of the crop or seedlings if you work in their gardens. Some gardeners I know have the same arrangement. Seek out sales. Garden groups often hold spring plant sales, offering significant discounts. Check with your local Master Gardener group to find out if they have a sale. Some public gardens also have plant sales.
Shop off season. Look for bargain plants and supplies at garden centers in late fall. Buy leftover amaryllis bulbs after Christmas. Book an arborist in the off-season to get a discount on tree pruning. Don’t overlook yard sales, thrift shops, and estate sales for discounted tools, pots, and other finds. Older tools often have plenty of life left.
Tap tech and barter. One garden writer found a woman on Craigslist too pregnant to dig her iris and strawberry beds. She did the digging in exchange for some rhizomes and runners. Check construction sites for free bricks and stones for paths and borders. One friend got a massive boulder by asking nicely. Another scored handsome old bricks, free for the hauling. Need free gardening advice? Call or e-mail your local Extension office with questions or send your questions and photos through our Ask Extension service. We’re here to help.
The garden savings go on and on. Take advantage, and don’t forget to pay it forward. Consider donating some of your seeds, harvest, and time to those who have helped you.
By Annette Cormany, Principal Agent Associate and Master Gardener Coordinator, Washington County, University of Maryland Extension.
Q: I have to remove a declining Flowering Dogwood, and would like to replace it with another white, spring-blooming small tree. Crabapple doesn’t appeal to me, and I already have a Magnolia. What would you recommend?
A: I think Fringetree (Chionanthus virginicus) is underused and quite showy. White is a common flower color for spring-blooming trees, native and otherwise, but for some reason this species is often overlooked. Growing wild essentially state-wide, it’s adaptable enough to handle home landscapes well if given good drainage and a half-day to full sun. Established plants have some drought tolerance, and grow at a similar pace overall to Flowering Dogwood (that is, slow to moderate, averaging a foot per year).
A member of the olive family, Fringetree is a cousin to Ash, and as such might be vulnerable to Emerald Ash Borer, the invasive insect that has decimated Ash trees region-wide over the past two decades. However, I think their susceptibility is low enough to give them a try, as I have not learned about any rampant problems with the beetle seriously damaging Fringetree, especially with the loss of most of the local Ash population’s mature trees.
A mature Fringetree (Chionanthus virginicus) in a landscape.‘Little Leslie’ is a dwarf cultivar that grows to a maximum height of 5 ft.
The olive-like dark blue berries produced by female Fringetrees are decorative and appealing to birds, but sexing trees is difficult unless they were propagated as cuttings from a tree of known sex. A lone female tree may not fruit if there are no males within pollinating distance, and male trees can’t fruit. Occasionally, a female tree might self-pollinate, but this is not the norm. If you have room, plant two and take a chance of having a pairing for pollination, or just enjoy the flowers (showy on both sexes), which are also scented.
Fringetree flowersFringetree fruits are eaten by many different bird species.
Other candidates for the criteria of white spring-flowering trees with a maturity smaller than a shade tree include: Serviceberry (Amelanchier species); Redbud (Cercis canadensis; there are a couple white-flowering cultivars); Hawthorn (Crataegus viridis ‘Winter King’ being widely available); American Plum (Prunus americana); Chickasaw Plum (Prunus angustifolia); Carolina Silverbell (Halesia species); and Snowbell (Styrax species).
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.
Confession time. I am more than a little obsessed with orchids. Why not? They are drop-dead gorgeous, the Grace Kelly of floral displays. Here’s their dirty little secret: some can be deceptively easy to grow. Phalaenopsis (fayl-eh-nop-sis) are the easiest to grow. Also called moth orchids, their round faces float above arched stems making them the darlings of home décor magazines.
And they are ever so undemanding. Just give them bright indirect light, very little water and a room with normal temperatures and they will be quite happy. Honest. Plus – drumroll, please – Phalaenopsis orchids bloom for two to three months starting right about now. Yes, that long.
I have a gaggle of orchid gals lined up on a table in my office, many of whom I’ve had for years. Last year’s birthday orchid (thanks, Dusty) bloomed off and on for six months. Just. Don’t. Overwater. That’s the primary cause of their demise. All they need is a gentle weekly spray of water in the sink. A tablespoon or two of water a week will do. Why? They are epiphytes. In the wild, they attach themselves to tree trunks and absorb the moisture and dissolved nutrients running down the bark during rain. They’re adapted to drying out in between rains because the root velamen acts like a sponge and holds moisture for a time. Those dangling “legs” growing up, down, and around are aerial roots. That’s what you spray.
In the wild, orchids drape themselves over tree bark and branches. They don’t need soil. The orchids we buy are in a special chunky bark potting mix that offers support and holds a bit of moisture. It’s okay to moisten that mix a bit and let it drain to boost the humidity. It’s also okay to add a bit of specialized orchid fertilizer to boost your orchid’s health and bloom time. Do you need a special orchid pot with decorative holes? Nope. But it does look kinda cool when those roots come rambling out aka Audrey in Little Shop of Horrors.
The most challenging thing about Phalaenopsis orchids is deciding which one to try. Petite or full-size? Fiery magenta, buttery yellow, or pure white? With or without contrasting veins, sepals, or spots? Stroll through any orchid display, and you’ll soon wear a slap-happy grin. Stay focused by looking for solid, deep green leaves, robust aerial roots, perky blooms, and many buds to maximize bloom time. Where should you look? Garden centers often have handsome plants, but I’ve found quite nice specimens at home improvement and grocery stores.
Once hooked, you might venture into other orchids such as Dendrobium, Cymbidium, Cattleya, or Lady Slippers. Forms vary from 6-inch ruffled blooms to cascades of tiny stars. And oh, the fragrances. Be dazzled by all the myriad colors and forms of orchids by visiting a public garden exhibit. Two outstanding collections are a day trip away. The U.S. Botanic Garden in D.C. has an annual orchid show, “Orchids: Masters of Deception,” from February 14 to April 27. And world-class Longwood Gardens offers an immersive experience with a floor-to-ceiling orchid display in their conservatory.
It’s easy to go overboard on orchids. And yes, there are support groups. The American Orchid Society’s website is a good place to learn more, as is our webpage. So, be bold. Try an orchid. It may become a delightful new obsession.
By Annette Cormany, Principal Agent Associate and Master Gardener Coordinator, Washington County, University of Maryland Extension.
I’ve been thinking a lot about habits lately—a whole lot. Changes in just one or two simple habits can radically transform our personal lives, society, and how we relate to the natural world, hopefully for the better but sometimes for the worse. How many of us have made a resolution or started a new habit already this year involving nature, gardening, or land stewardship? Are you sticking with it or just getting around to thinking about starting it? I am here to say: “If it matters, don’t give up!” It can take time and practice through repetition to establish or change a habit, according to an accumulating body of fascinating research around the human psychology of habits. A little bit of knowledge about how habits work can go a long way toward establishing and maintaining new habits.
The habit loop
Habits are a big part of what powers us through the day without having to think through the details of each and every step in a routine action. From wake up routines to commuting patterns, we carry out a series of regular actions based on established and regularly repeated cues, routines, and rewards. This is known as the “habit loop,” as vividly described by Charles Duhigg in his best-selling book, The Power of Habit: Why We Do What We Do in Life and Business.
Duhigg describes how habits, deeply encoded in one of the most evolutionarily ancient parts of our brains, the basal ganglia, relieve us of some of our daily cognitive load so that the more advanced parts of our brain can be devoted to higher order activities like reasoning, innovation, and decision-making. Habits can become ingrained fairly quickly if the chemical neurotransmitter reward in our brains is great enough, if the cues and rewards are strongly linked, or when routines are simplified and reinforced through regular repetition and behavior reinforcement.
Caption: An example of the habit loop illustrating part of my winter bluebird care routine. I spot a messy bird bath after a day of heavy use (visual cue), spring into action to scrub the basin and refill with clean water (routine), then enjoy the thrill of spotting a bluebird taking a drink of fresh, clean water the next morning (reward). My craving to see bluebirds in winter helps to power me through this frequent winter routine on freezing cold days. I suspect some endorphins are released in my brain every time I witness the scene of a bluebird drinking fresh water outside my window on a freezing cold winter day. Graphic: S. Small-Lorenz
Cue-routine-reward. Cue-routine-reward. A habit cycle powered by an incessant craving for a drop of neurotransmitter joy. Habits can become so routinely mechanized that they are difficult, yet not impossible, to change. It is entirely possible, though, to modify habits just through tweaking routines. It is also possible to create new habits through repetition, with clearly identified cues and rewards. To instill a new habit, it can help to establish the cue, the reward, and a simple sequence of action steps in between.
Caption: We lose the valuable benefits of leaf litter when we bag it and send it off site. Photo: S. Small-Lorenz
It occurs to me that the way we typically manage residential landscapes in Maryland is driven largely by culturally reinforced habits that may not always represent the best possible stewardship of our surrounding ecosystems. Feed the lawn with bags of manufactured fertilizer. Water that lawn with a hose tapped into municipal or well water. Mow the lawn with a roaring gas-powered machine. Rake or blow the leaves to the curb, prune and trim, then bag it all up and send it off in trucks to be dealt with off-site. There are exceptions, but as I travel through suburban Maryland, this is what I often see, all in support of a preferred aesthetic of an emerald green carpet lawn dotted with a few ornamental trees or shrubs offering low habitat value, with a high cost to our watershed, ecosystems, and climate. A whole series of lifelong, deeply ingrained lawn care habits multiplied across acres and miles depleted of beneficial insects, butterflies, and birds.
These habits also reflect missed opportunities to create better soil with higher soil organic matter that absorbs more stormwater where it falls, which would result in a more flood and drought-resilient watershed because soil with higher organic matter absorbs and retains more moisture. This, in turn, creates a foundation for a flourishing landscape that supports a wide array of biodiversity.
Keystone habits: Small actions that lead to big results
Then there are habits known as “keystone habits.” Like the architectural feature that supports an arch or keystone species that sustain an ecosystem, keystone habits are those habits that have the power to make big change throughout a system, by means of small actions. Small action = big change. It sounds so simple and gratifying, right? But is it realistic?
Duhigg gives examples of successful organizations and individuals who have identified and implemented keystone habits to achieve positive change and desired outcomes. These include daily habits drilled by Michael Phelps that helped him to break a world swimming record in an Olympic race, even while his goggles failed him, and former Alcoa CEO Paul O’Neill’s singular, unprecedented obsession with workplace safety that dramatically transformed its corporate culture and overall productivity, despite initial deep doubts and laments of indignant shareholders. Think about a life-altering habit that you have adopted, changed, or left behind. How hard was it but how much did it transform your life to eventually change that habit? Research has shown that cues and rewards of the habit loop can be difficult to rewire, but that it is also entirely possible to alter the routine between the cue and reward to achieve a more desired outcome.
My primary driving question these days is: “How do we change habits to improve habitat?”
As I review the many sustainable practices promoted through our Bay-Wise Living Landscapes Program, I am searching for those potential keystone habits that we should emphasize in 2025 that represent small actions for big changes. Small behavior changes across the landscape that, when added up, could have an outsized, beneficial impact on our watersheds and their ecosystems.
My 2025 keystone habit for Maryland
If I could foster one keystone habit change across Maryland in 2025 it would be this: “Recycle yard debris on-site.” This one habit actually captures a number of low-cost but beneficial practices, such as leaving leaf litter where it falls, leaf mulching, grass-cycling, and creating wildlife brush-piles from yard prunings. So, technically, we’re talking about habits within a habit.
Caption: Leaf litter (L) and a log under a layer of snow (R). Firefly larvae take shelter in leaf litter and logs throughout the winter. Yard “debris” has high habitat value, providing overwintering habitat for many beneficial insects and wildlife species. Photos: S. Small-Lorenz.
Managing our yard “debris” like leaves, grass, clippings, branches, stumps, snags, and prunings in ways that acknowledge their ecological value can improve soil and water, laying the groundwork for more climate-resilient landscapes and communities. Leaving leaves where they fall nourishes soil and vegetation, retains soil moisture, creates a substrate for native plants to establish, and provides an insulating ground layer of habitat for a wide array of species.
Leaf mulching and composting on-site are other sustainable options for managing leaf litter. Grass-cycling by leaving grass clippings on the lawn instead of bagging it up and sending it off-site provides a free, natural fertilizer with a much lower carbon footprint than trucking it off or applying manufactured fertilizer. Arranging downed limbs and pruned branches into brush piles provides shelter for songbirds and small mammals on extended snowy days like we’ve had this month and throughout the year and returns carbon and nutrients to the soil. (The main exception to this habit is to remove and properly dispose of invasive non-native plant materials, especially those that reproduce vegetatively or have gone to seed, to avoid spreading them.)
Caption: Brush pile in deep snow, surrounded by animal tracks. Photo: S. Small-Lorenz
How does habit change take root in the community?
However, pleading with people or even providing scientific evidence is not likely to make these habit changes take hold on a large enough scale to make a measurable impact across an entire watershed. Study upon study has shown that people are more likely to respond to a combination of seeing their neighbors do it and financial incentives over any amount of urging, pleading, pledging, or piles of scientific evidence (Bergquist et al. 2023). Could this be because neighbor cues and financial rewards better tap into this primal habit loop of cue-routine-reward? There is evidence that the answer to this question is “yes.”
Friction, cues, and incentives
In a fascinating review, Mazar et al. (2021) identified three successful strategies for motivating environmental behavior change through policy, and I believe these strategies are applicable to individuals and organizations as well. First is the strategic use of friction. Identify where friction can be reduced or increased to motivate habit change. Make it easy to implement the desired behavior (reduce friction) or a little more challenging to do it the old way (add friction). They cite a number of environmental behavior change studies, including one that made it easier to recycle by reducing steps to the recycling bin or a little more expensive to use disposable bags through token bag fees. This is a matter of simplifying the routine in the cue-routine-reward habit loop to lead to the desired behavior or complicating it to deter less desired behavior.
Caption: A blue male Eastern Bluebird points his bill upwards as he drinks water from a bird bath during a snowfall. An adjacent inkberry provides winter cover for birds. Photo: S. Small-Lorenz.
Eastern Bluebirds are fussy and require water to drink alongside their breakfast of shelled sunflower seeds and mealworms, which requires maintaining a clean, heated bird bath throughout the winter. In my own practice of wintering bluebird care, I had to find a way to reduce “friction” to make it easier to regularly scrub our heated bird bath during a busy winter work week, especially when it gets dark before I come home from work, and we have shut off outdoor taps to avoid freezing and burst pipes. We finally installed a simple adhesive hook under the sink so that I could easily find my special scrubber, and I now keep the watering can near the front door for easy refills. I found that I could vastly reduce the hassle of refilling and scrubbing the birdbath simply by making it easy to reach for my tools, speeding up the process and frequency of scrubbing the bird bath and heater. I simplified the routine so that the visual cue – a messy birdbath – more easily resulted in the reward – waking up to my bluebirds and their flock mates drinking clear fresh water right outside my front window.
“Re-setting the default” is a related strategy. A variety of studies have shown that setting the desired behavior as the default results in more rapid and widespread adoption of the more environmentally friendly option. For example, placing vegetarian meals at the top of a menu or adjusting office thermostat default settings resulted in significantly higher uptake of the desired pro-environment behaviors. In a different but related example, if I see salad at the start of a buffet meal, I will undoubtedly fill my plate with a bed of greens. If I encounter the dessert table first, you’d better believe I’m starting with the cheesecake!
Second is implementing clear cues to action – for example, studies showed that improving signage on cafeteria recycling bins using clear visual symbols right at the disposal site resulted in positive environmental behavior changes. I see this as directly tapping into the cue part of the cue-routine-reward habit loop.
Third is psychologically informed incentives that steer people toward desired environmental habits or away from detrimental habits. It turns out that people really like and value free things. Small fees, like the bag fee, have resulted in major societal behavior shifts by imposing a very small cost on the behavior of accepting a disposable bag. My local natural foods store takes it a step further by offering a wooden nickel token for each reusable bag a customer deploys, to donate to their choice of three local charities. There’s a double reward to accelerate that cue-routine-reward habit loop. Save the bag fee and donate it on the spot to a charity making a positive impact in the community.
Savor the intangible rewards
Rewards don’t always have to be financial, although small financial rewards or rebates have been shown to motivate environmental behavior change on a societal level. Rewards may come in the form of cost and time-savings or they may be as intangible as the smell of rich organic soil that you and your tree co-created, the endorphins released during the exercise of planting a common witch hazel shrub, the pleasure of seeing an Eastern Bluebird take a drink of fresh water from your clean, heated bird bath on a freezing winter day, or the joy of sighting that first firefly flicker of June.
Captions: Top: leaf litter, prunings, and standing woodland sunflower stems in the winter during a January snowfall event. Bottom: litter and songbird tracks in a light layer of snow. Photos: S. Small-Lorenz
If we can get comfortable with a slightly rougher and wilder aesthetic in our residential landscapes, the biodiversity and climate-resilience benefits could be immense. These new habits lend themselves to creativity – you can be as messy, manicured, or artistic as you would like with them yet still enjoy the benefits of rich soil, sustained soil moisture, pollinators, songbirds, hawks, and owls in your yard or park.
If you have resolved to become a better steward of nature this year, or even if you are just now thinking about trying your hand at some aspect of ecological landscaping, try putting your new knowledge of the habit loop to the test. If you’re looking for a place to start, join me in recycling your yard waste on-site in 2025. It may take a while to adjust and get the hang of this way of doing things, but once you get in the habit loop by identifying your cues, routines, and rewards, I predict that the workload becomes lighter, the cost savings will add up, and the many intangible rewards of being a better watershed steward right where you live will be noticeable and energizing.
References
Berguist, M. M. Thiel, M.H. Goldberg, S. van der Linden. 2023. Field interventions for climate change mitigation behaviors: A second-order meta-analysis. PNAS 120(13).
Duhigg, C. 2023. The Power of Habit: Why we do what we do in life and business. Penguin Random House. New York.
Mazar, A., G. Tomaino, Z. Carmon, W. Wood. 2021. Habits to save our habitat: Using the psychology of habits to promote sustainability. Behavioral Science & Policy, 7(2). Pp. 75-89.
By Stacy Small-Lorenz, Ph.D., Residential Landscape Ecology Specialist, University of Maryland Extension. Read more posts by Stacy.
Winter’s leafless landscapes, while beautiful in their own right, can look barren compared to the cacophony of color and activity of late spring/early summer. Once an oak’s leaves have senesced and its acorns have fallen, you’d think that not much is happening way up there in the canopy. But surprisingly there is! Tallamy’s The Nature of Oaks, takes the reader on a month by month journey of how these mighty trees support an abundance of life year round.
In fact, indigenous oaks (genus Quercus) support the highest number of Lepidoptera (butterflies, moths, and skippers) species in the mid-Atlantic region- some 534 different native species (Tallamy & Shropshire, 2009). Lepidoptera in the larva or caterpillar stage, such as the Greater Oak Dagger Moth (Acronicta lobeliae) (Fig. 1), often have a narrow diet breadth feeding on only a single family of plants. The over 500 species of caterpillars that oaks support, in turn, feed birds and other wildlife further up the food chain.
Fig. 1. Greater Oak Dagger Moth caterpillar. Photo: Nick Furlan
Tallamy’s Nature of Oaks gives numerous examples of insects’ impressive camouflaging, and describes how it helps them go undetected by hungry birds. For instance, the oak specialist American Oak Beauty (Phaeoura quernaria) blends in amazingly well with its host plant during both its larval and adult stages (Figs. 2 & 3). It’s no wonder that we often don’t notice all of the activity on oaks, especially given that much of it takes place at night.
Fig. 2. American Oak Beauty caterpillar. Photo credit: Adrian RomoFig. 3. American Oak Beauty moth. Photo credit: Basil Conlin
Tallamy also considers what’s going on beneath the canopy. Many oak-dependent species complete their life cycle in either the leaf litter or soil at the base of the tree. Research by our state entomologist and UMD alum Max Ferlauto shows that raking less results in more butterflies, moths, and beneficial arthropods. The harmful effects of leaf removal are widespread, impacting community composition, nutrient cycling, and soil stability (Fig. 4).
Fig. 4. Negative effects of leaf removal. Illustration by Maggie Lin
Of course oaks support a host of other arthropods and critters- from tiny wasps that form galls on oak leaves and terminal buds to numerous birds and mammals that depend on the trees’ nutrient rich acorns. Tallamy’s Nature of Oaks contains compelling data and entertaining anecdotes that left me awestruck by the beauty and interconnectedness of these mighty trees with all living things. Tallamy suggests if you can only plant one tree, make it an oak.
If you’re feeling inspired to plant an oak in your yard, Tallamy provides guidance on where and how to plant oaks for long term success. For instance, to overcome the concern of tree damage, he suggests planting young trees closer together (vs a specimen tree) so that they’ll be smaller in diameter and their roots will interlock. In Maryland, we’ve 21 native oak species that are commercially available, including two that reach a max height of 20 feet. For photos and details on growth requirements, habitat value, etc. see the new Commercial Maryland Native Plant List.
Where can you purchase native oaks (and other plants)? This month, the MD Department of Agriculture (MDA) launched a certification program for wholesalers, growers, and retailers of native plants. The program will make it easier for consumers to find sellers via a tiered system (novice, pro, and premium). Certified sellers will be listed on MDA, MD DNR, and UME’s web sites (coming soon). The program will also help consumers quickly identify which plants are native to MD via a new ‘Best Maryland Native Plant’ logo that retailers are encouraged to use on plant tags and signage.
If you’ve any questions or comments about growing or using oaks or native plants in general, I’d love to hear from you at lkuder@umd.edu.
Reference:
Tallamy, D. W., & Shropshire, K. J. (2009). Ranking lepidopteran use of native versus introduced plants. Conservation Biology, 23(4), 941-947.
By Lisa Kuder, Native Plants and Landscapes Specialist, University of Maryland Extension. See more posts by Lisa.
Winter Wonderlands are pretty to watch and enjoy with a lot of waterproof and warm clothes, but they also have their little challenges. For example, lots of snow can lead to a lot of compacted snow, that turns into ice, making Winter Wonderlands turn into Winter Slipperylands with all the accidents and issues that ensue. A common practice to reduce ice and its dangers is the use of de-icing salts. In this post, I want to talk about de-icing salts and how their excessive use can lead to unwanted consequences in our natural spaces and the organisms that inhabit them.
What are de-icing salts?
De-icing salts are most commonly sodium chloride salts, a non-food-grade version of the salts we use in our kitchens. Because high concentrations of sodium chloride in the soil lead to many environmental issues, alternatives exist, including potassium chloride, calcium chloride, magnesium chloride, and calcium magnesium acetate (CMA). Note, however, that although these alternatives are considered more environmentally friendly, they are just less environmentally harmful than sodium chloride.
All these salts generally reduce the freezing temperature of water, leading to water (ice) melting at temperatures at which it would have been frozen in the absence of the salt. Although this is a very simple and effective way of reducing or preventing ice formation, the intense use of salts leads to accumulation in the soil and water table, which is worrisome in many ways.
De-icing salts can degrade ecosystems when misapplied or applied unnecessarily. Photo: J. Jönsson (CC).
What happens if salts accumulate in the soil and water?
As we apply salts, they eventually dissolve in the water we are trying to de-ice, in moisture in the soil, and/or with precipitation. This salt then accumulates in the soil and in the water bodies into which the area drains. Both these processes can have strong effects on the health of the environment and the survival of many species.
Soils with high salt content are generally more toxic for plants (herbaceous and woody) that are not otherwise adapted to salty environments, leading to a negative effect on plant health and survival in regions where salts are applied intensely and regularly. For example, high salt content in the soil reduces the ability of plants to capture water and other nutrients and to tolerate low temperatures and drought. Further, when exposed to these high concentrations, plant tissues can also become enriched in salts, which can lead to cell dehydration and an inability to perform photosynthesis.
Reductions in plant diversity and health can also lead to other, more indirect effects. They can affect the ability of insects or other animals to find appropriate host plants to develop on and nest in and can lead to an increase in pest outbreaks, which are associated with reductions in the general diversity of the plant communities.
Besides accumulating in the soil, salts can also dissolve in the water and end up in the water bodies close to where the salts were applied. When salt use is very intense, it can lead to a significant accumulation of salts in lakes, streams, and rivers, which has demonstrated negative impacts on their organisms. Fishes, amphibians, insects, aquatic plants, and microorganisms display specific ranges of salt tolerance, and given that freshwater is not normally enriched in salts, the rise in its concentration leads to an inability for these organisms to survive under those conditions. Further, because some of the de-icing salts have phosphates, their runoff into the Chesapeake Bay can increase phosphate pollution and its negative effects on the survival of Bay ecosystems. Finally, it has been shown that high salt concentrations in water promote the survival of salt-tolerant organisms, one of which is mosquitoes. This can lead to larger mosquito populations in areas where there is intense and regular use of de-icing salts.
Does this mean that I can’t use de-icing salts anymore?
No, this means that because salts are not neutral to our environment, we should use them thoughtfully and cautiously. For example, shoveling or plowing snow before it becomes packed and icy is a great way to maintain ice- and salt-free spaces. Also, only applying salts when you’re sure that a storm will arrive is another way to reduce salt applications and its negative effects on the environment. Finally, if salts are needed, a good strategy is to apply them lightly and only to high-traffic areas. Don’t treat areas where there is no traffic. It has been shown that de-icing salt grains spaced 3 inches apart can readily and efficiently remove ice. Applying salts more heavily does not improve the de-icing action but increases salt concentration in the soil and water bodies.
Finally, if you do need to use salts on a regular basis, consider planting native salt-tolerant plants. For ideas, refer to this Salt-Tolerant Native Plants page from Virginia Cooperative Extension Master Gardeners in Northern VA. These plants will grow in Maryland, increase the biodiversity of your green space, and, in some cases, capture some of the salts in the soil, further reducing salt runoff.
Chesapeake Bay Program: learn how de-icing salts affect the health of the Chesapeake Bay.
By Anahí Espíndola, Associate 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!
