Cut peony foliage back to the ground if this hasn’t been done already.
Compost or discard foliage. Fertilize peonies twice a year — in the spring
shortly before new growth appears and then again in the fall after the
plants have been cut back. A total of 1.5 to 2 ounces (3 to 4
tablespoons) of a 1-1-1 fertilizer such as a 10-10-10 or 13-13-13 per plant
per application should be used. This amounts to 3 to 4 ounces of fertilizer
per year. If a soil test reveals adequate levels of phosphorus and
potassium, use a lawn fertilizer such as a 29-5-4, 27-3-3 or something
similar, but cut the rate to 1/3 of the above rate. In other words apply ½
to 3/4 ounce (1 to 1.5 tablespoons) per plant. Never apply fertilizer
directly on the center of the peony as the buds (eyes) may be damaged.
Rather, place the fertilizer in a band from 8 to 18 inches from the center
of the plant. Water the fertilizer in so the plant can take it up.
Winter protection of herbaceous peonies is only necessary the first winter
after planting to prevent alternate freezing and thawing from lifting plants
out of the soil. A couple of inches of mulch should be sufficient. Any
organic material that does not mat down will work and should be applied
after the ground freezes. Avoid using leaves that will mat together. Remove
the covering before growth begins in the spring.
The less common tree peonies have woody stems like deciduous shrubs and
should not be cut back to the ground or pruned in the fall. Collect the shed
leaves and place in the compost pile this fall. Though tree peonies are
hardy to Zone 4, they do benefit from a light mulching over winter. Also, it
is recommended that tree peonies be fertilized during November to get the
plants off to a good start next spring. It is best to take a soil test to
see what nutrients are needed. If the soil needs phosphorus and potassium,
use a complete fertilizer (such as 10-10-10, 9-9-6, etc.) at the rate of 2.5
pounds per 100 square feet. This would equal 1 rounded teaspoon per square
foot.
If phosphorus and potassium are not needed, blood meal makes an excellent
fertilizer.
Apply at the rate of 2 pounds per 100 square feet or 1 teaspoon per square
foot. Turf fertilizers such as a 27-3-3 or 30-3-3 also can be used but at
the rate of to 1 pound per 100 square feet or 1 teaspoon per 2 square feet.
By: Ward Upham