Harris County Master Gardener Offers Expert Tips for December Gardening
by Karen Shook, Master Gardener
Our 2023 fall has been near historic average temperatures, but a little drier. The forecast shows near historic temperatures with a good chance of higher than historic precipitation. With cooler temperatures, supplemental watering is probably not needed, but check for “too wet, too dry, just right” and water accordingly. Keep up with mulch. A two-to-three-inch layer helps maintain soil temps and deter weeds.
Continue gathering fallen leaves to use as mulch or as the “brown” in your compost. December is a good time for general garden clean up.
Reminder: First frost in Zone 8 is typically November 7 to November 28 and first frost in Zone 9 is typically November 25 to December 13. Be prepared to cover plants if needed.
Perennials and Ornamental Grasses
- Cut back perennials that have finished blooming. Cutting back ornamental grasses can be done, but you might like the tan color, seed heads as a winter display.
- No fertilizer is needed at this time.
Annuals
- Continue to plant cool weather annuals like snapdragons, pinks, poppies, calendula, stock, dianthus, alyssum.
- Fertilize only if plants are showing deficiency symptoms like pale or yellow leaves or stunted growth.
Bulbs
- Finish planting early blossoming spring bulbs including tulips and hyacinths.
- Cut back foliage that has browned. Mark the location of dormant summer bulbs. It is also a good idea to mark where you plant spring bloomers so you don’t accidentally dig them up or damage them digging in the vicinity. Check on the status of your stored bulbs.
Shrubs and Trees
- Shrubs can be planted and/or moved giving them time to get established before summer heat.
- Most shrubs will be dormant and can be pruned late in the month. Avoid pruning shrubs that bloom in the spring.
- Keep azaleas roots moist in cold weather to avoid damage.
Lawns
- Gather fallen leaves so they don’t shade your lawn. Or using a mulching mower, mulch them down into the lawn to help cover the soil surface and deter cool season weeds. Or gather them for mulch or composting.
- Unless you overseed with rye in the winter, not much is required for lawns in December. (Although I have a wood sorrel weed issue that I will likely choose to treat.)
-
Early December is a good time to plant or divide and transplant hardy groundcovers so they can form strong roots and be ready to grow next spring.
- Plant hardy perennial vines through the winter months with December prime time. No fertilizing needed until spring.
Edibles (vegetables, herbs, berries, fruits)
- See the following link for recommended planting times: Harris County Vegetable Planting Guide
Source: Harris County Master Gardeners Urban Dirt Newsletter (December 2023 Edition)
About Urban Dirt
Each month, Harris County Master Gardeners publishes an informative, resourceful newsletter entitled "Urban Dirt". This article was derived from the December 2023 edition. To read the December 2023 edition of this newsletter, click the button below.
