Putting the Perennial Garden to Bed

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An important factor for ensuring success in growing perennials is preparing them for their winter dormancy. Unlike annuals, only the top growth of the plant dies back each year. The root growth underground remains alive, and continues to develop for the next growing season. Therefore, it is vital that perennial plants have protection while they rest.

For the sake of tidiness, and to remove debris that may harbor insects or disease, most top growth is removed after it withers and turns brown. It has completed its work of nourishing the root system and fulfilling its propagation-related tasks of flowering and fruiting, or producing seed, for another year.

It is a good idea to apply a protective layer of mulch over the plant to maintain even soil temperature and avoid having the plant heave out of the ground because of wide soil temperature fluctuation. Use mulch that will permit the passage of air and moisture to and from the root system. To avoid damage by cultivation or accidental over planting, mark the location of the dormant plant with a stake or other marker that will not be easily uprooted or lost.

If you have prepared the garden soil properly with compost, the nutrients and moisture in the soil should sustain the plant during its dormancy. Fertilizing at this time is not recommended. An exception might be made in the case of clematis or other heavy-feeding vines. These may benefit from top dressing or mulching with well-composted cow manure around the plants to provide gradual feeding as well as protection.

Follow InfoLine instructions for pruning clematis. In all cases of perennial vines, be sure that any stems remaining above ground are tied to a support to avoid wind damage. Also, follow InfoLine instructions for over-wintering roses.

Dennis Patton, DPatton@oznet.ksu.edu
County Extension Agent, Horticulture
Johnson County, Kansas
Kansas State University Research and Extension