These Hydrangeas Flower Best When They're Left Alone

Q. We prune our hydrangeas in fall and for the last several years have gotten no blooms. Should we remove dead flowers? If we cut below the flowers into wood, will flowers be lost for the following year?

A. The Hortensia hydrangeas, which include both lacecaps and the so-called mop heads, flower on 1-year-old wood that grew the previous season. Because they flower later in summer, they are often mistakenly pruned like other late-flowering shrubs that produce flowers on wood of the current season. Therefore, if they are pruned hard right after flowering or in spring, many or all of the flowers will be lost.

These hydrangeas generally flower best if they are left alone, although in the case of larger, overgrown plants, some of the older stems can be removed at ground level each year after they have flowered. Stems and branches that have not flowered during a given summer will bloom the following season if they are not cut back. Those stems that have flowered during a current season may also produce flower buds for next season, so pruning these may also lead to loss of flowers next season. But these also are the stems that should be shortened, if size reduction is important.

Crew cutting or heading back all stems each season will reduce or eliminate flowering. If very large, overgrown hydrangeas are cut completely to the ground during the winter, no flowering will occur until the following year. Some gardeners leave the spent flower heads on until spring with the idea that they will provide winter protection to the flower buds below them. This practice is probably questionable. Flower buds can usually be identified by their relative plumpness. They are much fatter than vegetative buds. If they are pruned away, the flowers are lost.

Q. There's a squirrel in my yard stripping bark from my lilac. Will it die?

A. Any stems that are completely stripped of bark will die. Since lilacs sucker readily from the root system, it's not likely the whole plant will be killed, at least not in one season. On the other paw, if your squirrel friend continues his action over a period of years, your lilac will probably never flower, and it could eventually be devitalized to the point of succumbing.

Q. How can I control moss on the soil around my raspberries and other perennial garden plants?

A. Any iron compounds applied to actively growing moss will kill it, and shouldn't harm your plants. However, don't get it on the foliage of any desirable plants. Tilling the soil or covering the moss with a couple of inches of mulch should also help to eliminate it.

Q. How do I divide hostas?

A. If hostas have enough room to spread they really don't have to be divided on any sort of regular basis. However, during the dormant season, late fall to early spring, the clumps can be lifted with a spading fork and separated into smaller sections. You may need a spade or other sharp implement to carry this out. Make sure that each smaller division has at least three to five eyes (buds) on it.

Q. Can I transplant a tree peony and chrysanthemums now or should I wait until later in spring?

A. Both plants can be moved anytime during the dormant season, ao long as the temperature is above freezing.