Thursday, July 31, 2014
Inquirer Daily News

Garden Q&A

Question: I have two clematis growing on trellises, each about five years old. I have never trimmed them back, and each year I'm rewarded with more and more beautiful blooms in the spring. This year, their size became a problem, pulling the arbors over from the weight of the plants. Underneath the new growth were dried vines with no leaves or blooms. Now that all the leaves have fallen off, I'm wondering if I should trim it back.

- Lisa Miller
Answer: Don't do anything now. The earliest clematis pruning is late winter - but it all depends on which clematis you have.

There are three groups of clematis, with different pruning requirements. Do you know the names of your clematis? If so, see the Web sites mentioned below. If not, now you have a prima facie case of why gardeners should keep plants labeled.

But here at Crime Scene Investigation: Vine Land, the evidence will likely resolve the matter. Group 1 clematis bloom only in the spring (usually early spring) with one large flush of flowers; they do not bloom again until the next spring. Group 2 blooms first in late spring and then will have repeat blooms later in the summer, though they may be smaller than the first ones. Group 3 blooms in late summer or fall.

Prune a Group 1 clematis only after it has flowered, and no later than July 1. You can be as modest or radical as you wish when you prune.

Prune Group 2 in late winter. Remove all dead material and, for best flowering, prune each remaining stem about two feet from the end, just above a pair of plump (or sprouting) buds. If you wish to substantially reduce the size of the plant, you can prune more radically, though flowering the first year will be reduced.

Prune Group 3 in late winter. Cut everything to two feet from the ground. This sounds ominous, but if it is a Group 3 clematis, the results will be excellent.

This Web page has pruning information: www.savvygardener.com/Features/clematis_pruning.html. This Web page has lists of varieties and their group classification: www.taunton.com/finegardening/pages/g00156.asp.

Q: We just took down an elderly, infested streetside sycamore and want to replace it with something that will add to the neighborhood canopy but that won't take forever. The tree will share yard space with a substantial magnolia that's about 20 feet tall. Suggestions? Autumn color would be nice (sycamores are seriously unrewarding in that regard).

- R.A.K.
A: Here are three possibilities, two of them native Americans. Sourwood, Oxydendron arboreum, has brilliant scarlet foliage. In early summer, its panicles of little white flowers can seem to blanket the foliage; they have prompted another common name, lily-of-the-valley tree. The drawback is its slow rate of growth - in 10 years it might not reach 15 feet.

Another native American with rich fall column is Nyssa sylvatica, the black tupelo tree. Because of its taproot, you must acquire a relatively young tree for successful transplantation, which tree guru Michael Dirr recommends be done in early spring. But if successful, a tree with a taproot is excellent at curbside, as opposed to, say, maples, whose surface roots are a bad match for curbs and sidewalks. Tupelos grow faster than sourwoods, but not much.

Or consider a ginkgo. Don't recoil over the tree's deserved reputation for foul-smelling fruit. Ginkgos are dioecious - like hollies, there are females (with fruit) and males (without). Nowadays, it's hard to find a female gingko for sale. Almost all named cultivars are male, propagated vegetatively.

There are narrow forms (fastigiate is the hort-speak term), such as Princeton Sentry and Fairmount, which originated from a tree found in Fairmount Park and which is available commercially. Others, selected for deeper yellow fall color than the typical ginkgo, include Autumn Gold, Saratoga and Shangri-la. Ginkgos are relatively fast-growing.


Send questions to Michael Martin Mills, The Inquirer, Box 41705, Philadelphia, Pa. 19101 or gardenqanda@earthlink.net. Please include locale. Read his recent work at http://go.philly.com/ michaelmartinmills.

Michael Martin Mills Inquirer Columnist
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