Photos by Elaine Mills unless otherwise noted
Winter Gardening Tasks
Deal with winter storm damage
- Herbaceous plants and most trees will be fine during snowstorms, but evergreen trees and shrubs are more likely to be damaged by heavy loads of snow and ice.
- Excess snow can be dislodged by using a broom to gently lift and shake branches to prevent breakage.
- Broken and hanging tree branches can be pruned as needed without waiting until spring. For details, see Assessing and Dealing with Snowstorm Damage on Trees.
- Plants like Arborvitae may recover by taking these steps:
- Tie multiple stems together
- Place stake next to bent-over plant
- Tie gently to woody plant leader
Deal with potential salt damage
- Spray or runoff of dissolved de-icing products used on roads, sidewalks, and driveways causes dehydration of plant roots, resulting in damage to a plant’s entire vascular system.
- This ”salt burn” damage is most noticeable on foliage, especially that of evergreen plants.
- A solution to this problem on our own properties is to use products that don’t contain salt. For helpful information on alternatives, see Beyond Road Salt: Winter De-Icing Options.
- Promotion of deep root systems can help plants resist damage, and sensitive plants can be sited uphill or 50 to 60 feet away from paving.
Salt-tolerant native trees & shrubs
A survey of 10 university and Cooperative Extension websites, indicates that these species are most salt-tolerant. Eastern redcedar appears on 6 lists; magnolia and serviceberry on 5 lists; holly on 4; and the others on 3 lists each. For more information, see Trees and Shrubs That Tolerate Saline Soils, Salt Spray, and De-Icing Salts.
TREES
SHRUBS
Other salt-tolerant native plants
These plants are native to coastal dunes or saltwater/brackish marshes and/or can tolerate spray from roadside salt applications. See Best Bets: Salt-Tolerant Native Plants for details.
GRASSES, SEDGES, AND RUSHES
FORBS
Sow native plant seeds
- Growing native plants from seed is an economical way provide new plants for the home landscape. Because these plants are adapted to local growing conditions, they can be easily grown without a greenhouse.
- Seeds for propagation can be obtained from some native plant sellers, through seed exchanges, such as Washington Gardener Seed Exchange, or from a new local seed library at the Glencarlyn Library Community Garden in Arlington.
- See resources on saving, sharing, and starting seeds prepared by Master Gardeners.
- View two videos for more information:
- Winter Seed Sowing, Audubon Society of Northern Virginia
- All the Dirt on Winter Sowing Native Plants, UMD Extension
Photo © Elaine Mills
Do winter pruning
Native Evergreen Trees
- Removal of multiple leaders, dead or broken branches of native trees can be done at any time.
- Native evergreen trees seldom need pruning, but if pruning is desired, the best time for most species is December to February.
- For hemlock & pine, the recommended time is April to June.
- With holly, it is especially important not to prune during its bloom period from April to June or berries will not form on female trees.
- See Evergreen Tree Pruning Calendar for details.
Native Deciduous Trees
- For some native deciduous trees, the timing of pruning is not critical. A good time for those species pictured at the right is December to February.
- With birch, it is critical not to prune during the sap-flow period which begins in February.
- Other native deciduous trees should be pruned after blooming for fruit to form. See Summer Tasks (forthcoming) for details on appropriate species.
- See Deciduous Tree Pruning Calendar for details.
- Be sure to consult a certified arborist for advice and technical assistance.
Native Shrubs
- Native shrubs can be pruned anytime to correct damage or remove diseased branches.
- Otherwise, many native shrubs require little pruning. If desired, those that bloom on “new wood” can be pruned during the winter. These are plants that will bloom on the current season’s new growth.
- A shrub such as red twig dogwood can be pruned to encourage new growth. Up to 1/3 of its older brown stems can be removed to spur the growth of showy new red stems.
- Some shrubs can tolerate periodic “hard pruning” close to the ground for rejuvenation. They can regrow as much as 3 to 5 feet and still bloom in the spring. Examples include:
- Consult the chart on Native Shrubs to Prune in Winter for details on additional native species.
- See a short video on Winter Pruning and a recording of a public education class on Pruning Trees and Shrubs for general information on pruning techniques.
Remove invasive English Ivy vines
Photo © R. Olsen ARMN
- Winter is a good time to remove invasive vines that are growing on the trunks of trees, so they won’t weigh down and smother the trees. These are easier to spot when deciduous trees have dropped their leaves.
- The method recommended by our Arlington Regional Master Naturalists:
- Cut runners of the vine at around 2 to 3 feet up the trunk of the tree.
- Gently peel the runners down to the tree roots.
- Continue to remove runners and root as far around the base of the tree as possible.
- Bag cut sections and place in the trash. (Ivy can regrow from even small root sections.)
- Allow the remaining ivy on the trunk to die. The leaves will blow away.
Control winter weeds
- Winter is a good time to get on top of the control of common weeds that begin appearing during the cold months.
- This will prevent the build-up of seeds in the soil that will continue to sprout later in the year.
- See a short video on Winter Weeds for more information and a Weed Resource Page for advice on identification and control.
- The video on Tips, Tricks, and Tools: Advice from Master Gardeners introduces a handy tool, the Hori Hori soil knife (1:01:58), which can help with removal of these plants.
Common Winter Weeds
Do a soil test
- Native plants have adapted to local soil conditions, drawing the nutrients that they need, and do not require fertilization.
- Some native plants prefer “lean soil,” and they should not be interplanted with annuals or non-native perennials that require feeding.
- The salts from fertilizers can burn native plants or make them weak and floppy.
- You may want to do a soil test before starting new bed to check the pH (acidity/alkalinity) and the organic matter content (decomposed material from recently living organisms).
- See a short video on Gardening Basics: Doing a Soil Test and Interpreting Your Soil Test for more information.
Acid-loving Native Trees
- It’s important to know the soil preferences of plants to site them properly in the garden. Trees generally prefer soil pH below 7.0, in the acidic range
- Trees are not compatible with alkaline-preferring turf grass, so it’s critical to avoid the use of lime fertilizer near tree roots.
- Creating wide mulched and planted beds around trees also protects them from damage during mowing of surrounding lawn.
- Some native trees prefer soil in the pH range of 4.5 to 6.5, including those pictured at the right.
Acid-loving Native Shrubs
- Acid-loving native shrubs in the Heath Family (Ericaceae), such as those in the top row on the right, prefer a pH range from 4.5 to 6.0.
- Other native shrubs (pictured below) also favor a pH range below 7.0.
- On the other hand, some native shrubs prefer alkaline conditions from 6.1 to 8.5:
- Buttonbush
- Carolina Rose
- Fragrant Sumac
- Common Ninebark
- Native Plants for Wildlife Habitat and Conservation Landscaping lists the preferred pH for many native plants.
