Your Guide to Winter Plant Care
Wondering how to care for your plants in the cold? The green thumbs at CA are here for you! Through every season, CA’s Open Space crew is dedicated to helping hundreds of plants thrive across 3,600 acres of open space. CA’s Weed Warrior volunteers are also full of sage advice.
While different plant species vary in their specific winter care needs, check out their best tips to guide you.
Plant native species ๐ฑย
The plants you choose are important! Native species are well adapted to withstand the climate of their region, so planting native species sets your garden up for success.
When selecting plants, keep plant hardiness zones in mind. Hardiness zones are based on the average lowest temperatures in the area. According to the 2023 USDA Hardiness Zone Map, Columbia is in zone 7a, which means the average minimum temperature is between 5ยฐF and 10ยฐF. Plants in this zone range are more likely to withstand the winter, so always check the information on the plant tag.ย
Another helpful resource: CA’s Invasive Plant Resource and Reference Guide. You’ll find a list of harmful invasive plants to avoid.
Embrace winter conditions โ๏ธ
Here’s your “winter garden” checklist from CA Conversation Landscape Specialist Eric Walker: ย
โ Cover your garden. Cover up bare soil with leaves, compost or mulch to create organic matter and provide insulation.
โ Cover the base of trees and shrubs using leaves or compost. This provides moderate insulation of roots – just be careful not to bury the area where the roots meet the trunk. Ground-dwelling native bees nest in the ground during the winter, so avoid using wood chips or mulch, which can interfere when these bees emerge in spring.ย
โ Start pruning. Winter – ideally late February – is a great time to prune shrubs and trees before buds break in the spring. Click here for more information on pruning from the Maryland Department of Natural Resources.ย ย
โ Sow native plant seeds during the dormant season. Did you know native flowering plant seeds need several months of exposure to cold to germinate in the spring? January and early February are great times to throw out native seeds in the frozen soil by hand – this is called “frost seeding.โ Click here for more information on winter seed sowing from the Audubon Society of Northern Virginia.ย
โ Do a soil test. Soil tests reveal crucial details about macro and micronutrients in your soil, which can be used to help with plant selection. Click here for more information on soil testing from the University of Maryland Extension. ย
Don’t “over clear” your garden ๐ซ
According to CA horticulturist Jackson Sides, going overboard with cleaning up garden debris is a one common mistake in the winter.
For instance, leaves make a great natural mulch, so leave them in your flower beds. Also, try to resist clearing out dead plant material – native pollinators nest in leaves and hollowed out stems. If you do want to give plants a little haircut, focus on the top and keep the stalks intact. Most pollinators lay their eggs in the bottom 10 inches of a plant, so this helps protect them.
Watch the forecastย ๐ฅ๏ธ
If a cold snap is coming and it hasn’t rained lately, consider watering your garden. This may sound counterintuitive, but moisture produces heat when it condenses, so moist soil helps keep your plants warm. If you can, bring potted outdoor plants indoors when freezing conditions are on the way. Certain pots and planters (such as terracotta) can crack when frozen. ย
Trees need TLC, too ๐ณ
Here are a few tips for caring for young trees from CA Weed Warrior Kate Reilly:
- Tube or cage any tree with a trunk the diameter of 4″ or less to protect it from antler rubbing from September to late winter (pictured left).ย
- Prune young trees while they are dormant, cutting out crossed or rubbing branches or other undesirable branches.
- Refer to the United States Forest Service’s โฏTree Owner’s Handbook โฏfor expert pruning advice.ย
What about indoor plants? ๐ชด
Their needs change in the winter, too. A few considerations:
- Adjust watering. Just like outdoor plants, most indoor plants need less water because they experience less growth in the winter. Every plant is different, but it can be helpful to push your finger into the soil. If itโs dry an inch or two below the surface, itโs time to water. Pro tip: Use room-temperature water to avoid shocking the plant’s roots.
- Evaluate location. Your indoor plant may need to be relocated to a spot that gets more sun in the winter (i.e. a south- or west-facing window). Itโs also best to keep your plant safe from cold drafts or sources of prolonged heat, such as the oven or fireplace.
- Amp up the humidity. Humidity drops in the winter, but you can still keep your plants humid and happy! Consider keeping plants in the bathroom or kitchen, where theyโre naturally exposed to more humidity. You can also huddle plants together, or place plants on a tray of water with pebbles and stones.ย
Dream about your spring garden ๐ธ
“During the winter, I put leaves around and over my perennials and under all my trees and shrubs.โฏ I also leave seed heads and plant stems for the birds.โฏ Mainly, I dream about what I plan to do with my garden next year!” -Susan Tucker, CA Weed Warriorย ย