A Woody Ornamentals Trial Comes Of
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Entrance arch Story and photos by Alan Weninger A Woody Tucked in behind the busy intersection of College Drive and Preston Avenue in Saskatoon is a place that has been called the Ornamentals Trial city’s best kept secret. A shady retreat of mature trees between grassy rows, this is the University of Saskatchewan’s arboretum, a Comes of Age botanical collection of woody plants. A horticultural experiment begun in 1966, Patterson Garden has now passed the 40-year mark, and the long-term answers to the questions posed at that time are now ready for interpretation. What’s more, the trees are mature enough to have a significant presence, and let’s face it: with trees, size does matter. Patterson Garden began life as a test site for the adaptability and hardiness of various species and cultivars of tree, shrub and vine to the prairie climate. As part of the Prairie Regional Trials for Woody Ornamentals, it was one of Caragana (Caragana aurantiaca) seven such sites across Manitoba, Saskatchewan and Alberta. In the late 1950s, flower soldiers the Morden Research Station (Agriculture and Agri-Food Canada) in southern Manitoba began to propagate plant material from its arboretum collection to 30 T HE G ARDENER FOR T HE P RAIRIES distribute to co-operating institutions for Of course, Patterson Garden is more than Tian Shan mountain-ash testing. Successes and failures at the test just a botanical treasure: it declares itself a (Sorbus tianshanica) sites were recorded over several years, with garden by name, a place for people. Gardeners, trials officially coming to an end in 2001. nursery growers, picnickers, walkers, tree Unfortunately, many of these original test sites nuts, kids’ camps, visitors to Saskatoon, are now in a state of decline, perhaps because students and researchers enjoy the garden. of changing priorities. Patterson Garden For a research area, it has a very park-like feel however has persevered, with some ups and to it: there are grassy rows to wander down, downs, and it is now in a good state of health. regardless of weather; the trees have mulched rows to protect and nurture roots. Robins and Dr. Cecil Patterson, for whom the Garden is other birds nest here, and a nesting pair of named, was the first Head of the Department Swainson’s hawks return to a nearby tree year of Horticulture at the University of after year. Patterson Garden is not kept within Saskatchewan. From 1922 until his retirement a research station as are some of the other in 1960, he served the University and the trial sites; it is open to the public and fairly Swiss stone pine cone public through his teaching, writing, extension accessible, if perhaps a bit hard to find. (Pinus cembra) and research. From 1922 until 1942, Dr. Patterson was responsible for all landscaping My own introduction to Patterson Garden on campus. A generous and passionate man, came from a University co-worker some he worked to produce better plant varieties years ago. Standing under the scarlet oak, for prairie horticulture (especially lilies, my first thought, “This oak can grow here?” vegetables and fruit trees), and to bring was followed by “Why aren’t there more of gardening knowledge to people living on the these?” I still don’t really know the answer to prairies. It is fitting that this prairie garden, an the second, but it has something to do with important link between the University and the familiarity and economics. I repeated the first public, is dedicated to him. question under the canopy of the Amur cork tree, while With close to seven hundred individual marvelling at its exotic bark accessions, Patterson Garden is one of the and interesting leaves. largest collections of woody plants on the prairies. Many of the collection’s species and Now, fifteen years later, my cultivars are fairly rare in cultivation, although own scarlet oaks and Amur the more common trees, shrubs and vines are cork trees are big enough to also included. Present are maturing specimens stand under: not only did the of Amur cork tree (Phellodendron amurense), Patterson Garden collection scarlet maple (Acer rubrum), Japanese elm stir my imagination, it also (Ulmus japonica), Manchurian ash (Fraxinus led to a tree-growing hobby mandshurica) and Swiss stone pine (Pinus that takes up more of my cembra); several specimens in the collection time and my thoughts than I are rarely seen in cultivation, such as the Tian care to admit. Shan mountain-ash (Sorbus tianshanica). In If you do find your way some cases, such as with Korean arborvitae to Patterson Garden, look (Thuja koraiensis) and scarlet oak (Quercus for the arborvitae, or white coccinea), they are the only surviving trial cedar (Thuja occidentalis) row specimens other than the original plants at the near the centre, behind the Morden Research Station. Mockorange memorial plaque to Dr. Cecil (Philadelphus spp.) flowers The collection also includes many Patterson. Normally assigned heritage cultivars of roses, crabapples and roles in foundation plantings Moth-sized Cotoneaster leaf other flowering plants that were the result of and uniform hedges, here these plants are early plant breeding on the prairies. Also, a given some space and individuality. Some of large number of native species are present, these trees have a ‘deep, dark forest’ mood to including silverberry (Elaeagnus commutata), them, similar to their rainforest cousins, the black spruce (Picea mariana), Canada western red cedar (T. plicata). At the far end buffaloberry (Shepherdia canadensis), narrow- of the arborvitae row, look for the silver maple leaved meadowsweet (Spiraea alba) and that has spread out in all directions to create nannyberry (Viburnum lentago). Patterson a huge sheltering canopy. The poplar (Populus Garden is essentially a library of hardy woody spp.) row is not far beyond, with enormous plants, labelled and filed into rows, always specimens of Berlin poplar and cottonwood changing and growing. hybrids. T HE G ARDENER FOR T HE P RAIRIES 31 Lichens When you tire of being dwarfed by tall and study material, and even for pruning trees, consider the potentilla, or shrubby workshops. Researchers at the Horticulture cinquefoil (Dasiphora fruticosa) row beside Field Lab also use Patterson Garden for a the silver maple: even though they are two source of plant material for breeding purposes. feet in height, many of them are as old as the Many schools manage to use the arboretum maple. Then consider the lichens on the plant for science programs or for a first-hand labels: a few centimetres in diameter, they may botanical experience. Meewasin Valley be as old as the potentilla. But Authority (MVA), which uses adjacent land if this kind of deep thinking for a plant nursery, conducts a stewardship is not on your list of how to Flower petals, crabapple row program for grade 4 students and uses enjoy yourself, visit in the Patterson Garden to teach tree and shrub spring when there are flowers identification. Garden tours often take place in everywhere. In May and June the summer for interested groups, organised there are endless varieties by the Plant Sciences Department and the of lilac, crabapple, cherries, Horticulture Field Lab. spirea, caragana, currant and viburnum in full bloom. Although 42 years is a relatively long time to run an experiment, Patterson Garden is just It’s true that big trees are coming into its prime. The fastest growing of a big deal, but there is also an the large trees, the hybrid poplar, have mostly interesting new crop emerging reached their peak and passed on. For the in Patterson Garden. As old trees with longer life expectancies, it is difficult specimens die off, new spaces to say how long they could last. It is possible are created that are now being for oak, ash, elm, linden and many conifers filled up. The arboretum is to last a few hundred years. Saskatoon is still climatically different than it a relatively young city; we really don’t know was 40 years ago: the trees the life expectancy for many of these species have created their own shelter under our urban conditions. We can only from the winds, the city has grown and with hope the trees will still be there a hundred it, its radiant heat. This new environment years from now, perhaps having survived road allows for some new species for trial, and more expansions, climate change, disease and pest than one hundred plants have been added in outbreaks, and the number one killer of tree the last few years. The planting emphasis has collections: neglect, due to changing priorities, been on species plants, for maximum diversity funding cuts and perceived lack of economic in the limited space available, but some new importance. cultivars are also being squeezed in. Remember Patterson Garden the next time Patterson Garden, more than anything else, you are heading out for some fresh air, or Silver maple (Acer saccharinum) canopy demonstrates diversity: unexpected botanical wanting to identify the leaf that you found the variety for the northern plains. This variety other day, or trying to decide what to plant in gives us choices and ideas for our landscapes, your landscape. You don’t have to be a botanist be it flowering trees and shrubs, evergreens, to enjoy the garden, but it might steer you a drought tolerant species or native plants. This little in that direction. genetic diversity also increases the odds that there will be some species or individual trees Patterson Garden is maintained by the surviving if a severe pest or disease outbreak Plant Sciences Department of the U of S, as should ravage our urban forest.