Very few, if any, people complain about unseasonably warm weather in November. It shortens winter, which most years can feel far too long. For the most part, warm falls do not have detrimental effects on plants.
Perennials will continue to absorb moisture and store it for winter. The tops of some varieties die back and go dormant with the first killer frost, but others remain green until the ground freezes or they are covered with snow. A late fall gives perennials more time to develop roots.
Spring bulbs do best when they planted and winter comes late as they, too, have more time to become established.
Evergreens continue the uptake moisture until they go dormant later in the season. Warmer weather will cause the plants to transpire or lose more moisture. In many places the soil is wet but unless it is saturated, take time to water evergreens to ensure they have adequate moisture to last until spring. The simplest way is to leave a hose trickling around the drip line or outer branches of the tree or shrub. Feeder roots are found in the first 12 inches (30 cm) of the soil surface.
Wrapping an evergreen for the winter, or shielding the side that receives direct or reflected sunlight will lower the plant’s transpiration rate.
Deciduous plants that bloom early in the season set their buds during the growing season. The size of the buds that overwinter depends on the plant. When there is a cold spell followed by unseasonably warm weather the buds will swell. A few buds might open, but they usually stop expanding once the temperature drops.
If by chance the flower bud breaks, enjoy the flowers now knowing that the plant does not have time to develop new ones for next spring. Not producing flowers for a year will not harm the plant.
Frost resistant plants that were left in the garden, kale, spinach and Swiss chard, will continue to grow. Harvest and enjoy.
Garden seed that has been planted in the fall for spring germination could germinate. For this to happen, the soil temperature must reach a certain temperature, and contain enough moisture to support new growth. In the fall as in early spring, the moist soil is usually cold.
A warm fall is a great time to transplant. Most plants are dormant and do not lose as much moisture due to transpiration. Be sure to water all plants that are transplants regardless of the moisture level in the soil.
Lawns will continue to grow. Mow when needed. Leaving grass long over winter is an invitation for rodents to visit. It also makes it much harder to clean in the spring. On the other hand, too short of grass leaves the grass roots without winter protection. Lawns overwinter best if they are between three and four inches (eight to 10 cm) long. Removing leaves in the fall helps prevent them from molding.
The weeds in the lawn and flowerbeds will continue to grow. Once the ground freezes annual weeds will die and perennial ones will stop growing and expanding. They will continue next spring once the snow melts.
Plants, especially the native ones will not suffer due to warm fall weather. Spend time outside and enjoy.
Linda Tomlinson is a horticulturalist that lives near Rocky Mountain House. She can be reached at your_garden @hotmail.com