Will Mild Winter Force Spring?
Several readers have expressed concern that the warm winter will cause plants to flower and grow. There is no need to worry about native plants in our climate initiating growth or flowering before spring.
Mother Nature took all of these factors into consideration when selecting plants that belong here. In our climate, native plants start preparing for winter in mid-August. Growth begins to slow, scales grow to protect the vegetative buds through winter, and spring-flowering plants develop their flower buds. In other words, the plants ready to go dormant.
For dormancy to be broken, both time and cold are important. Before the buds can grow, chemical changes must inspire them.
These chemical changes occur only between 32 and 44 degrees. The changes do not occur at temperatures below 32 degrees, and they occur very slowly below 44 degrees. Depending on the species, the period when these chemical changes occur can vary by several hundred hours. Until the dormant-causing chemicals are destroyed by cold and time, the plants will not resume growth.
This is not to say that all buds will remain dormant. There are times when buds from the previous season will initiate growth in the fall because they did not grow as they should have in the previous spring.
There are times that a late summer drought will force buds to initiate partial dormancy. Early rains can force some of these buds to start growth in winter when the weather warms.
But by most standards, we need not worry that an Indian summer or a thaw in mid-winter will force native plants into premature growth.
On non-native plants, we have little data to describe the effects of warm winter weather. Data follow funding; without funding, any knowledge is gained by scientists in their areas of interest at their own expense.
Time to Cut Back Ornamental Grasses
By the end of January or the middle of February, most ornamental grasses are starting to look like the Wreck of The Hesperus. This is when I take my power hedge clippers and, starting at the top, cut away the top six inches and continue cutting away six-inch layers until I come within six to eight inches of the crown. The cut grass makes an ideal mulch that will control weeds and will compost well in place.
Ask Dr. Gouin your questions at [email protected]. All questions will appear in Bay Weekly. Please include your name and address.