Most flowering perennials are not heavy feeders, and once established, may not need fertilizing every year. However, a soil test or visual symptoms will help determine plant needs. Weak plants with light green to yellowish foliage will probably benefit from a nitrogen-containing fertilizer. In the absence of a soil test, apply a
10-10-10 or similar fertilizer at the rate of 1 pound per 100 square feet.
Fertilizer should be applied as growth begins in the spring.
Perennials that tend to need more fertilizer than the average perennials include astilbe, chrysanthemum, delphinium, lupines, and summer phlox. A second application during summer may be helpful for these plants. (Ward
Upham)
