Washington ? How many times have you been in the garden and discovered a sprouting acorn or a winged maple seed erupting into life, and muttered to yourself, “I should put that in a pot”? But then you think life’s too short to wait for a tree to grow. You might also see hundreds of oaks, maples or elms sprouting from the bumper seed crops of this year and last, and regard them merely as stubborn weeds.

But starting a tree from a seed is not just fun and rewarding. It’s a way to vegetate your landscape cheaply while fighting global warming and preserving biodiversity.

For Henry Kock, a horticulturist at the University of Guelph’s Arboretum in Ontario, it became an obsession. He spent more than two decades learning the singular germination needs of various native trees and shrubs, and decided he would share his secrets with others in a new book, “Growing Trees From Seed” (Firefly, $45).

Raising slow-growing giants is an exercise in patience and foresight, qualities not valued too much these days. But talk to people who are hooked on this, and there is a palpable sense of accomplishment and satisfaction. Gardeners are used to slowing down, of being servants of the natural cycles of the seasons, but sowing little acorns for mighty oaks that one will never see takes a special degree of forethought.

Kock’s book offers this quote from Bernd Heinrich, professor emeritus of biology at the University of Vermont: “Planting nuts requires a vision for a future that goes beyond one’s mortal reach. If we envision ourselves as participants in the same grand, complex web of interactions as the forest, then planting acorns is like planting part of ourselves.”

This became poignantly so for Kock, who died on Christmas Day 2005 at age 53. He associated his cancer with pesticide applications he made between ages 14 and 28.

Traditional techniques

In studying horticulture, Kock learned traditional techniques of propagating new plants by cuttings or grafting. But when he came to the arboretum, he found an inveterate seed collector in curator John Ambrose, so Kock got hooked on making new plants from seeds and, through trial and error, figuring out the optimum methods for each species.

You might think the horticultural world had already figured this out, but pros much prefer to propagate woody plants from cuttings or by grafting. These methods replicate the desired traits of the donor plant (a yellow flower, for example, or a variegated leaf or a dwarf habit) and provide a predictable plant that can be mass-produced for the market.

The resulting good news: Every plant is a clone of the other. That’s also the bad news.

Seed-grown trees and shrubs are more varied and unpredictable and certainly more genetically diverse. “That’s the whole beauty of growing trees from seed,” Ambrose said. “If you have a whole street of cloned trees, one disease could come in and wipe them out.”

There is also aesthetic value in natural variety. Ambrose recalls seeing cloned trees and shrubs in fall colors and all of them in identical plumage, whereas seed-grown individuals would present a striking tapestry of, say, reds, oranges, maroons and yellows.

Ambrose was one of three of Kock’s professional acquaintances who stepped forward to finish Kock’s unpublished manuscript. The others are Paul Aird, a forest conservationist, and science writer Gerald Waldron.

Dos and don’ts

Two salient points raised by the authors: It’s not OK to help yourself to tree seeds in public gardens and parks; seedpods, fruits and nuts are part of the decorative and educational qualities of plants on public display. If you’re collecting from private property, ask permission first. Second, make sure you can identify the parent tree. You may think you are propagating a lovely native red maple tree while you are actually spending a lot of time and trouble raising a Norway maple, an invasive alien.

Just as veggie gardeners find the biggest or most disease-resistant heirloom tomato and save the seed, a tree hugger should look for seed from a particularly robust, beautiful or ancient mother plant. A tree that has lived to great age has shown a genetic resistance to pests, disease and drought episodes.

Other issues

There are other pitfalls. Acorn season is brief because nuts left on the ground are likely to be visited by various species of pesky weevils, whose adults and larvae feed on acorns and turn the meat brown. Fallen acorns untouched by weevils can simply dry out after a week. Kock tells us that healthy acorns sink in water; weevily ones usually float. Acorns are best sown in a protected outdoor seedbed (a chipmunk-proof cold frame would be ideal) and then allowed to receive the necessary chilling period of winter before sprouting the following spring. If you don’t have a protected nursery bed, mimic winter by putting the acorns in the fridge for several months without letting them dry out.

Versatile project

Growing trees from seed would be a perfect enterprise for anyone with a rural property in need of habitat restoration, Ambrose said. But it works in urban and suburban sites as well, he said. Though Kock died relatively young, Ambrose said, “he created this amazing little forest in a downtown back yard.” It lives on, alongside his guiding hand and inspiration.