When To Prune A Clematis Vine? Well, It Depends

Q If you don't know which kind of clematis you have, is it better to err on the side of not cutting the vines back, or to prune them?

A. The time of flowering dictates pruning practices for clematis. If you have absolutely no idea what you have, watch the vine for a year to see what it does.

If it blooms in the spring, such as a Clematis macropetala, the blooming wood is produced in the previous year. Trim in spring after flowering, not as the foliage emerges in spring.

Summer bloomers, such as the common clematis jackmanii, bloom on new wood produced in the spring. Trim these in spring, cutting back hard. (Leave 2 feet or less of wood.)

Just to confuse the gardener, some clematis bloom in spring and again in summer. Prune these lightly in fall to tidy them for the spring bloom, and then cut back hard after flowering to prepare them for the summer bloom.

You may also want to take a flower into a nursery to attempt exact identification. There are also some splendid books on clematis which you could consult at the Elizabeth Miller Library, Center for Urban Horticulture, University of Washington. Hours are 9 a.m. to 8 p.m. Monday and 9 a.m. to 5 p.m. Tuesday through Friday.

Q: With ajuga and other voracious ground covers, do they grow well with bulbs or do they mat over the area so the flowers can't grow?

A: Combining ground covers and bulbs takes some manipulation. In general, there's little problem with the first-year plantings of bulbs, because opening the hole to plant them will also give them some space to emerge. And first-year bulbs come supplied with the carbohydrates they've stored while being grown.

The difficulties come in subsequent years. Consider the bulb's needs for sunshine, oxygen, water and nutrients to rebuild itself after blooming. If the surrounding ground cover has persistent, matting roots or if it chokes the plantings closely, the bulbs may not replenish themselves well enough for another season.

Gardeners manage bulb plantings by planting them near other perennials and allowing the emerging foliage of the perennials to cover the space left by bloomed-out bulbs. Experiment with your plantings and see what works.

One handsome planting that persisted for a long time in a sunny Seattle garden had King Alfred daffodils planted under a low-growing, shrubby cotoneaster (possibly Cotoneaster dammeri). Remember that eventually most bulb plantings will need replacement. Bulbs which seem to deal best with ground covers are crocus (they'll even come up in grass) and various narcissus.

Q: I want to plant tulips that will bloom in spring, summer and fall - various types. But I can't find a catalog for ordering them. Do you have any ideas?

A: Brilliant tulips in spring gardens are ordered in midsummer and fall for planting in the fall between October and December. Their period of bloom extends from early March for the smaller botanical varieties into May for the late, large Darwin and Cottage tulips. Many of the catalogs are organized in order of bloom, and you'll find it possible to enjoy more than two months of gradual unfolding of early, midseason and late tulips.

They can't be bought or planted in spring, nor are there varieties which bloom during fall. Like many garden joys, the pleasure of tulips is in the fleeting season for enjoying them. Observe them now in Northwest gardens and make your list for next fall's planting.

Q: I notice my neighbor puts her dog and cat poop in her garden. I was told many years ago that this is not a good idea. What's the scoop?

A: Pet-refuse disposal presents some dilemmas. Adding pet wastes to a compost pile is neither advisable nor pleasant; cat waste in particular carries organisms which can infect humans, particularly pregnant women.

One possibility is to dig holes 10 to 12 inches deep and bury the pet waste, covering it completely.

Also, there are some commercial systems specifically designed for treating pet refuse.

Gardening runs Friday in Scene and Sunday in Home/Real Estate. It is prepared by George Pinyuh and Holly Kennell, Washington State University/King County Cooperative Extension agents; Mary Robson, Master Gardener program assistant; and volunteer Master Gardeners. For questions, you can reach us 24 hours a day by dialing 464-8470 and recording your question. Or, write: Gardening, c/o Seattle Times, PO Box 70, Seattle, WA 98111.