Warmer-than-usual December temps bringing some plants out
Years ago, there was a television commercial that ended with the statement, “You can’t fool Mother Nature.” (I forget just what the commercial was for!) That is true. But Mother Nature can sure fool us.
Historically warm weather experienced throughout much of Ohio this fall and through the month of December is fooling plants in central Ohio into thinking that the growing season has begun and that it is time to bloom.
Temperatures for most of December were well above average throughout Ohio, with many locations experiencing one of the top five warmest Christmas Days on record with observations dating back to the 1870s, according to National Weather Service statistics.
In addition to the warm temperatures, December was wetter than normal in central Ohio with more than 4.5 inches of rain. Soil temperatures were also warmer than normal and not close to freezing. The result is that many plants in central Ohio are breaking dormancy up to two months earlier than normal, with some in full bloom.
Spring flowers bloom early
Several species of early spring flowers are blooming throughout central Ohio. Early spring bloomers such as snowdrops and crocus were in bloom between Christmas Day and New Year’s Day in several locations in central Ohio, nearly 4 to 6 weeks earlier than normal.
Daffodils have also begun to actively grow with green shoots breaking through the soil surface in some locations. Short-lived perennial flowers, such as pansy and snapdragon, have begun to flower in some protected locations where they had been growing last summer.
We have also seen new growth appear on hardy herbaceous perennials such as sedums. A return of more typical January weather with freezing temperatures should not cause lasting damage to the longterm health of these hardy perennial plants.
Trees could be in peril
Buds on some species of shade and fruit trees have begun to swell with some early bloomers, such as silver maple, appearing that they could flower this month if warm temperatures were to persist. Buds on some fruit trees have also begun to swell early in preparation for flowering.
While cooler temperatures recently have and will continue to slow development of buds on trees, the danger is that a return to warmer temperatures even for a few days intermittently will cause continued expansion of buds and early flowering and leaf-out, making them susceptible to a late winter or early spring freeze while they are flowering.
This type of weather pattern is especially dangerous to fruit trees such as peach. While most shade trees and ornamentals can survive freezing temperatures during flowering, freezing temperatures will cause blossoms to fall from peach trees terminating fruit production for the season.
Bumper crop of lawn weeds
Warm temperatures in December produced a
bumper crop of cool-season lawn weeds such as chickweed, purple deadnettle and ground ivy, which have overrun sparse stands in some lawns. A return to cooler temperatures below freezing will slow the growth of these cool-season weeds.
As gardeners, we should expect that weather extremes such as warm weather in December will become more commonplace with a warming climate. Like the plants we love, we will need to adapt to changes in our environment.
Mike Hogan is an associate professor at Ohio State University and an educator at the OSU Extension.hogan.1@ osu.edu