Q: Spring is here and I’m wondering if now’s the time to divide perennials. How do I do this?

A: Spring and fall are good times to divide perennials. Choose a cool time of day and dig up a clump with many shoots showing. Shake away soil to expose the central rhizome or stem. With a sharp knife, cleanly slice the plant into several pieces and leave at least two or three growing points on main plant or it may take many years for the plant to recover. Locate plants in soil prepared with compost and keep moist until well established. Dividing plants takes some practice, so you start with one clump, developing skills to apply to larger planting areas. For more information, visit planttalk.org for #1018, “Perennials: How to Divide.”

Q: My neighbor and I share some large ornamental grasses planted very close together. They did well for several years, but now two of them look dead in the center. What can we do to bring them back to life?

A: Ornamental grasses are very popular in our landscapes and are relatively easy to maintain. However, overcrowded grasses can lose vigor and attractiveness over time. When the center of the grass clump dies, leaving grass blades visible only around the edges, division is necessary. Spring division, before growth starts again, is the most successful time to divide for grasses such big bluestem, little bluestem, switchgrass, Miscanthus and Pennisetum. Cool season grasses like blue oat grass, blue fescue and ‘Karl Foerster’ can be divided in late summer and fall.

Divide grasses by cutting the foliage back to four to six inches. Dig the entire clump up from the ground and using a sharp spade, knife or axe, cut through the core and halve the clump completely and then divide into quarters. Check to see if each division has a good root system and discard dead or diseased material. Replant divisions as soon as possible, water well and protect with three inches of mulch. Visit planttalk.org for #1068, “Dividing Ornamental Grasses.”

Q: How much pruning is helpful to fruit trees before they flower?

A: Yearly pruning in late winter or early spring, before bud break, generally helps fruit trees. It is recommended that no more than one third of the total growth on a tree be removed in one season. If heavily pruned, many fruit trees produce water sprouts which produce no fruit and grow vertically from normal branches. Visit planttalk.org for #1210, “Pruning Mature Fruit Trees.”

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This page updated:  April 29, 2008