The short days and cool nights encourage many of the perennial plants to go dormant and prepare for a long winter's nap. With this in mind, fall is a good time to clean up annual and perennial flower beds.
Although many gardeners have put their tools away for the winter, there are still a few gardening chores that need tending. Here is a brief list of flower bed "to do's" that can be finished this weekend.
Normally, I recommend "clear cutting" dead stems of annual and perennial flowers during the fall to help control insect and disease problems. However, if your herbaceous perennials have been pest-free, you might consider leaving some dormant stems to provide structure, form and color to the winter garden. For example, ornamental grasses may be attractive even during the winter months.
Likewise, those perennials with evergreen or semi-evergreen foliage may provide color if left untrimmed.
Other benefits of leaving dormant plant parts include:
Foliage left on marginally hardy plants, such as mums and tender ferns, helps protect young growth next spring.
Seedheads of some perennials supply winter food for birds.
Remaining plant parts help remind you where plants are located when doing early spring chores. But for the most part, perennials are naturally messy after that first killing frost and should be trimmed back.
Following cleanup, feed your perennials. Fall is a great time to fertilize sleeping plants. Even though they may look dormant, the root system is actively growing and absorbing nutrients for spring growth. Apply one pound of actual nitrogen per 100 square feet of bed. For example, apply 10 pounds of 10-10-10 type fertilize per 100 square feet. Water the fertilizer in if rain is not expected in the next few days.
Finally, if you recently planted or have perennial flowers that are shallow rooted, it is best if you mulch them for the winter. Use a loose organic material such as old straw, compost or shredded leaves from the yard.
The thermal blanket helps keep the soil temperatures constant and prevents the plants from being heaved from the soil by the freezing and thawing actions of winter temperatures.
As the fall gardening season comes to an end, so do our gardening activities. One of the last areas of the landscape that needs tending are the flower beds. A quick fall cleanup, the addition of fertilizer, and a light blanket of mulch will help ensure your perennial flowers make it through this winter.
Bruce Chladny is horticulture agent at K-State Research and Extension-Douglas County. For more gardening information, call the Master Gardener Hotline, 843-7058, between 9 a.m. to noon and 1 p.m. to 4 p.m. Monday, Wednesday, or Friday.