Even as attention shifts to holiday happenings and indoor events, our generally mild December weather means that we can still enjoy time outside tending to the garden.
Thankfully our temperate climate and infrequent frosts make year-round planting possible, and December is still a good time to plant deciduous trees and shrubs, replant containers, or to make a final push to plant Spring-blooming bulbs.
December Gardening To Do List
Seasonal Color
Now that most leaves have dropped, we look forward to the stars of the Winter garden: ‘Yuletide’ Camellias, Cyclamen, Coral Bark Japanese maples, colorful Heaths and Heathers, Wintergreen (berries), and Red Twig Dogwoods all show vibrant shades of red or crimson now and will look great in containers and flower beds all Winter long.
Plant Camellias as food our year-round resident Anna’s Hummingbird. These small and colorful hummingbirds love to visit Winter-blooming Camellia blossoms for sips of nectar to stay warm and energized. For holiday-appropriate red blooms, plant ‘Yuletide’ Camellias. And if you prefer pink over red, ‘Pink-a-Boo’ is a fragrant option that blooms around the same time with perfectly pink ombre flowers that are equally loved by hummers!
Planting, Pruning & Maintenance
Keep an eye on the forecast and protect new plantings against Winter weather events as necessary:
- Use Harvest Guard or floating row covers offer winter protection to tender plantings and evergreens with sensitive buds or Winter flowers.
- Keep in mind that wind can also be damaging, especially when combined with cold temperatures—use stakes to support plants, provide windbreaks, and/or apply MoistureLoc to help plants retain moisture and reduce evaporation during extreme weather.
Provide adequate watering to plants that don’t receive rain:
- Make sure plants in greenhouses or cold frames, containers, and sheltered areas (under eaves) receive adequate water.
- Water new plantings and evergreens thoroughly before cold weather arrives.
- If heavy frost warnings or below freezing temperatures are in the forecast, water plants before it freezes—use a watering can or bucket if hoses are stored for the season.
Prune selectively to minimize damage to plants.
- Remove dead branches from trees and shrubs as needed – branches that are damaged or may cause damage from winter wind or snow and ice.
- Cut roses to waist/chest high to reduce winter damage to plants.
- Thin shrubs and trees only as needed (further pruning may result in new growth that won’t harden off before winter).
Turn compost piles and cover with a tarp to protect from heavy winter rains.
Keep up with sprouting weeds: Short spurts of weeding done during this time can greatly reduce your spring weed crop!
Scatter slug bait (Sluggo or Slug Magic) while you’re in the garden—slugs remain active during mild weather; you can significantly impact future population by controlling them now!
Edible Gardening
Do a soil test for pH and primary nutrient levels (use home test kit or consult Master Gardeners for a mail-in test).
Spread wood ashes from the fireplace on vegetable gardens evenly and sparingly; use no more than 1.5 lbs per 100 square feet per year. Do not use ash if the soil pH is greater than 7.0 or potassium levels are excessive.
Shelter bare patches of garden soil with a layer of mulch, compost, or shredded leaves to reduce erosion and compaction from rain.
December Lawn Care
Watch for drainage problems during heavy rains: Spring or fall lawn renovations, berms, bioswales, rain gardens, and French drains are great solutions for poor drainage.
Contact our Residential Landscaping Department to arrange for services at 503.777.7777.
Indoor Gardening in December
For festive indoor color: Buy a fresh, colorful poinsettia or Christmas cactus. Protect poinsettias from cold, provide plenty of light, and don’t let the leaves touch cold windows.
Monitor houseplants for adequate water and drainage; watch for pests and other early signs of trouble (water and fertilizer requirements are generally less in winter). Plants may struggle with low humidity as indoor air becomes dryer from heater and fireplace usage. Increase humidity levels by misting plants frequently or by using a pebble tray.
If you need to move a large indoor plant to accommodate the Christmas tree, be sure to keep the plant away from furnace/heater vents, cold windows, and drafts from frequently used doors.
What to Do for Fun in December
Attend Reindeer Magic! This family-favorite event at our Lake Oswego and Vancouver nurseries features live Reindeer, Santa, live music, local food and gift vendors, and so much more!
Create festive porch pot arrangements in your empty containers: Fill empty flower pots and outdoor containers with soil (or use leftover soil); purchase fresh-cut branches of evergreens (noble fir, incense cedar, juniper, holly. outdoor ribbon and lights to shine for the holidays!
Feed the birds in the garden: Now is a great time to bird-watch from the kitchen window and admire tiny flocks of finches, juncos and bushtits feasting on the last seeds of fall. Keep feeders clean and refill regularly.
View the garden tips and checklist for January in the Garden. Or go back and view the tips and checklist for November in the Garden.