I have a neighbor who says she has the same problem; yet a street away, a vine facing the south blooms abundantly. What type of fertilizer should I give it? Does it take a few years for it to get established before it blooms? -- M. S., Liverpool.
Dear M.S.: Failure to bloom is a problem that comes up frequently. There are several possible explanations. One is your suggestion: juvenility. The plant is simply too young to bloom. Flowering is the equivalent of puberty. It's a sign that the plant is ready to reproduce.
That concept is easily grasped. What people have trouble understanding is that plants vary tremendously in the timing of their life cycles. "Wisconsin Fast Plants," famously used by teachers (and by students who didn't get their science projects under way on time), grow from seed to flower in 14 days. They are a type of turnip or mustard green, Brassica rapa.
Annuals, by definition, grow from seed and flower in one season. Biennials, by definition, grow the first season and flower the second.
Other types of plants, especially woody plants, take much longer to mature. I planted a dove tree, Davidia involucrata, about 15 years ago. I don't expect it to bloom until it is 25 years old or so. That's longer than most trees and shrubs common in the nursery business. Five to 15 years is typical. Most people don't want to wait even that long, so precocious blooming is a trait breeders look for.
Grafted stock tends to bloom sooner after planting than seedling stock. The top grafts are cut from wood that is of flowering age, so that quality carries over to the grafted plant.
Conditions of all sorts can influence maturity as well. Light is significant. Plants will not bloom if they don't get enough light. Trumpet vine, Campsis radicans, being native to the southeastern United States, likes a fair amount of heat and won't do well in short, cool, wet summers.
Fertilizer is not generally a factor. If the soil is not sufficiently fertile, other problems will show up first. The growth may be stunted and the leaves off color. Excessive nitrogen will actually prevent blooming in many kinds of plants because growth is directed toward making leaves instead of flowers.
Improper pruning is another common cause of failure to bloom. Whacking away at the wrong time of year may cut off all the flower buds. Trumpet vine blooms on new wood of the season and grows vigorously. The vine can be pruned hard in the early spring. Summer pruning will reduce the numbers of flowers.
Carol T. Bradford, of Syracuse, has been gardening in Central New York for more than 25 years. Send questions in care of Home & Garden, The Post-Standard, P.O. Box 4915, Syracuse, NY 13221, by fax to 470-2111 or by email to email@example.com. Letters might be edited for space and clarity.