sustainablelandscaping
Local genetics present business opportunity
BY SEAN JAMES
Times are changing.
It wasn’t that long ago that there wasn’t enough demand for plant stock grown from local seed to make it more than a boutique business. Nowadays, nurseries are being established that cater, successfully, to demand for conservation initiatives and, at long last, residential installations. If you are faced with a difficult site, native plants may be your best option, especially if grown from local seed. Why? Native plants are adapted to our local soils, climates and even pests. Each region has its specific challenges, such as Calgary’s chinook winds and southern Ontario’s wet winters and humid summers. How local is local? At VanDusen Gardens in Vancouver, a planting of Mexican white pine had random dieback one winter — a tree here and there. When the botanical garden in Mexico, the source of the seed, was contacted, it came to light that some seed was collected from the top of a mountain and some seed from a lower altitude on the mountain. The genetic differentiation was that specific; different adaptations from the same mountain. Growers of natives run a complex business, drawing seed from many sources and em-
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ploying a variety of growing techniques. I recently had a chance to tour St. Williams Nursery and Ecological Centre in St. Williams, Ont., and asked my tour guide Dave Turnbull about the challenges and benefits of running a specialty nursery, growing plants from local seed stock. According to Dave, “Collecting, storing and maintaining seed and plants across a range of seed zones within a large territory is a logistical challenge. Locating seed source (donor) plants and monitoring for health and being assured of trueness to the species,” is also an important factor since some different species in a genus can be very similar. Other species cross naturally in the wild making it an even bigger challenge. Turnbull adds, “The number of seed donor sites will vary by species to ensure adequate genetic variation to support the biodiversity of each community/location and the broader the genetic diversity of the seed collected, the more stable the genetic foundation for the ecosystem into which it is going. Multiple visits to seed donors help ensure one doesn’t select from only the early- or late-maturing species, thus missing important genetics contributing to adaptability to withstand changing climates, envi-
ronmental conditions and invasive species.” It’s a very complex business if you’re going to do it right and, since this is the UN Decade of Biodiversity, doing it right is important! He points out, “Weather is another challenge. Some seeds, such as sugar maple, can dry out on the tree, whereas a wet year can adversely affect pollinators, causing poor seed set. Even “other” collectors competing for the seed — squirrels, chipmunks, etc. – can be very effective and timely too.” Many species don’t even set seed every year, with some being on a five- to seven-year cycle. Storing and cataloguing the seed is important, and each species has its own recipe for storage/germination. Some plants are rare in the trade since they’re notoriously difficult to propagate, such as maple-leafed viburnum. Others, such as white oak, must be collected and planted immediately after they fall lest they lose their viability. At St. Williams, field rows of seed stock have been planted as a solution to ease the seed collection of many species. “These stock rows are generally replaced after a few years to ensure genetic variability.” Dave explains. St. Williams has been creating stock areas with great success — an idea which was not