One of the highlights of a holiday to northern Italy was to unexpectedly find myself in what I thought was the middle of a forest of Swiss stone pine (Pinus cembra). When I was told that the Italian common name for this tree was cembra, I grinned from ear to ear.
Native to the European Alps and into Asia, Swiss stone pine has a narrow, upright, columnar to pyramidal form, eventually reaching a height of 12 metres. The needles are long, soft and in bundles of five. The bark is smooth and light grey, becoming scaly with age. Relatively slow growing, they are extremely hardy, resistant to winter sunscald injury, very attractive, trouble-free, and sadly underused. They are excellent in a mixed border or as a specimen tree, especially in a smaller landscape.
Similar to the Swiss stone pine but slightly smaller, the limber pine (Pinus flexilis) is also a good candidate as a specimen tree in a smaller landscape where larger conifers could be overwhelming. Native to British Columbia, Alberta and North Dakota, it reaches only nine metres and is often multi-trunked. Although moderately slow growing, it can live for several hundred years. The bark is light grey and very smooth. The needles are blue-green and in bundles of five. Incidentally, the Swiss stone pine is one source for pinenuts, ingredient in pesto and other delicious dishes, gut you may have to wait 10 years or more for your first crop.
While ponderosa pine (Pinus ponderosa) is a great tree in every way, it has an enormous natural range, from British Columbia southward with a lot of variability in size and hardiness - not all selections do well on the prairies. Look for the subspecies, Pinus ponderosa var. scopulorum or the Rocky Mountain yellow pine. This one is a smaller, more compact, hardier version of the species. It is native to the Black Hills of Â鶹´«Ã½AV Dakota and grows well on most of the prairie region. So read the small print on the tag and ensure you have the correct one.
With a deep and wide-spreading root system, it reaches 20 by six metres with a straight trunk with dark grey bark. The canopy is broadly pyramidal. The needles are generally in bundles of three, dark green to yellow green and sharp pointed. Each scale on the cone ends in a rigid, sharp prickle. The bark is dark grey.
For anyone who has explored the Cypress Hills of Saskatchewan and Alberta the lodgepole pine (Pinus contorta var. latifolia) is a familiar sight. It is also native to the Rocky Mountains. The common name refers to the use of the long straight trunk in teepees and lodges by First Nations who also used the resin for waterproofing canoes, baskets and moccasins.
Surpassing 20 metres in height, it has a lifespan of up to 200 years. The needles are dark green to yellow-green, in bundles of two, twisted and sharply pointed. The cones persist on the tree for 10 to 20 years. The root system consists of a deep taproot and spreading lateral roots.
Lodgepole pine is useful in a large landscape for screening, as a specimen tree, and in shelterbelts. It seems to be much more widely available in North Dakota than the Canadian prairies.
As in last week's article these conifers do best in full sun on well-drained soil and are drought-tolerant once established. And before planting, ensure that mature size matches the size of your yard.
- Sara Williams is the author of the newly revised and expanded Creating the Prairie Xeriscape.This column is provided by the Saskatchewan Perennial Society.
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