Snowball Bushes

Q. I have had a "snowball bush" for 4 years. It bloomed the first year only. Some of the tips of the leaves are turning brown. What can I do to get it to bloom?

A. There is a Common Snowball (Viburnum opulus 'Roseum') and a Japanese Snowball (Viburnum plicatum) Bush. Japanese Snowball grows 7 to 12 feet tall with maple-like lobed leaves 3 1/2 inches wide. Common Snowball Bush is the most common that grows 6-10 feet tall.

What is the general health of the plant? You might want to check the soil fertility and pH soil type and water/sun situation. I suspect not enough water in hot weather and more fertilizer needed. A pH test kit is easily available at a garden center. Make sure than the soil is properly drained irrigated and there is enough phosphorus [look for a high middle number on the label] for flowering. They do need some help after all!

The snowball bush does not require more than a soaking once a week -- perhaps 5 gallons applied slowly says University of California master gardener Bill Pierce. Too much or two little water can influence flowering. It tolerates alkaline or acid soils and grows in part shade to full sun. Snowball bush is a spring bloomer; therefore it is critical to prune at the correct time. Fall or winter pruning will remove flower buds. Prune only after bloom has finished. The bush is subject to aphids thrips spider mites and scale. Any of these infestations could cause bloom failure. Most of these pests can be eradicated with a strong blast of water applied daily for 3 or 4 days. Your plant may be perfectly healthy and just needs more time to become established before it will bloom more.

If you have a cooperative extension agency or a nearby university with a horticultural department you might bring a branch in to them for further evaluation but the brown edging sounds like lack of water.

A. Snowball bush is applied to several plants the Japanese Chinese and European Snowballs which are all Viburnum varieties. Japanese and Chinese Snowballs bloom in spring and their flowers often remain for up to three weeks. European Snowball an old fashioned variety is subject to attacks of disfiguring plant lice so is not as desirable.

In general spring flowering plants bloom from buds formed the previous season. Any serious pruning is done just after flowering so the plant can set buds for the following year. Sometimes a little light trimming can be done during the dormant season. Most viburnums don't need much pruning. When they get overgrown and need thinning the oldest trunks can be cut off at the ground and the younger more vigorous shoots left to grow on. Most are big shrubs. When they get too large they sometimes need to be cut back although this may destroy the graceful shape of the shrub. Occasionally when shrubs get too tangled and overgrown they can be renewed by being completely cut back to the ground in spring (after enjoying the flowers) and fertilizer is spread around them on the ground. Sometimes they take two or three years to bloom well again. The English often renew their shrubs in this manner.

A. I tried this method to propagate Annabelle hydrangeas and a few other hardwood branches. It may work for your snowball better than cutting off a flower bud and placing it in a soil mix. Make a small nick in the underside of one lower branch. Weigh down the branch so that the nicked branch is on the ground. Cover that portion of branch with compost and light soil and allow to root. Keep evenly moist but not water-log or the stem will rot. Protect from any strong sunlight.