By Art Vanderkruk, Connon Nurseries, A.V.K. Nursery Holdings Inc., Rockton, Ontario

For a number of years I have wanted to tell the horticultural world about certain trees that are very easy to take care of. These are trees that, when given the right conditions, will grow very well with very little care and which will enhance many a landscape. Environmental concerns, cost of production and a recent call from Landscape Trades has given me the stimulus to make this idea a reality. There are virtually hundreds of these trees available to us if we would only stop, look, listen and read.

     Although “native” is currently all the rage, not all native plants are easy to care for. In fact, some are very troublesome and can cause a great deal of added work and expense. This, however, is an equally valid argument when using non-native plant material. When one plans a landscape, a park or has the urge to plant a tree, the first consideration should be the site and what is available to the plant (i.e. soil condition, drainage, air quality, sun, shade and water). Once this is determined, you can then choose the appropriate plant material available for the site, be it “native” or “non-native.” We should choose the best from all categories.

     In an economic environment where we try to get the most for the least, we should consider plant material that will perform best with the least amount of work and expense. In growing trees for over 45 years, I have discovered some plant material very appealing to the eye, yet easy to care for. “Low-maintenance trees” is exactly what the terminology implies when we consider habit, rate of growth, pruning and staking requirement, disease and pest control. The trees considered in this article are chosen from both native and non-native trees. Here are a few of my favourites.

Abies balsamea
Balsam Fir
Height: 20 m
Zone: 3
Having recently moved, our new place has a number of native trees, including a Balsam Fir only five feet from the house — a totally inap­propriate place as this species will grow to 20 m (60 ft.) or more. In time, it will interfere with the eves and roof and will need to be removed. Until then, we are enjoying it immensely and it is a wonderful haven for birds. It is an easy tree to grow, it requires little pruning as it is naturally symmetrical and has few disease and insect problems. In its natural environment, it is found in a wide variety of soils, however it thrives in well-drained sandy loam soils. Seedlings spring up in dense populations after harvesting lumber or after forest fires. In the landscape, this tree may be planted in groups or as a specimen. It has a shallow root system so mulching would be desirable to preserve moisture.

Acer campestre
Hedge maple
Height: 12 m (larger at times)
Zone: 5
This medium-sized maple, grown mostly from seed, is usually rounded and densely branched. Other forms are sometimes observed due to genetic diversity in the seed. Rich dark green foliage lasts into late fall, then turns yellow. It is excellent as a small lawn specimen and is not troubled with serious diseases or pests. This tree can be easily pruned, which makes it an ideal city tree where utility lines are prevalent. This tree is used for hedges in Europe and will also tolerate some air pollution. It will grow on a wide range of soils and is very tolerant of high pH soils. We have grown Acer campestre for many years and it is easily the least demanding tree in the nursery.

Fraxinus nigra ‘Fallgold’
Fallgold Ash
Height: 15 m
Zone: 3
The literature today does not include many positive comments about the genus Fraxinus. One begins to wonder if ash is good for only axe handles and firewood. Yet, there are several hundreds of thousands of ash trees planted throughout North America annually. Is this a contradiction? Many varieties of ash are inexpensive to produce and will tolerate adverse conditions, which explains a lot. Black, blue, green and white ash are native and account for approximately 50 per cent of the total ash grown. Then there are the dozens of good cultivars available to the trade — Cimmaron, Patmore, Summit and Autumn Purple, to name a few. All are unique in character and colour. These account for most of the rest being planted. Ash is an excellent choice when planting parks, open spaces along highways and large residential lots. The key to success, however, is to make certain that the soil is rich, deep and properly drained. Too often trees are not given the required elements needed to guarantee successful growth. This probably accounts for many problems in the landscape today. Many nurserymen seek and select new varieties of ash in the hope of finding yet better varieties. I am sure we’ll have even better selections in the future.

     Fallgold black ash, a seedling selection from a native stand in Manitoba, is a handsome medium-sized ash, with dark green leaves growing to approximately 15 m high. Fallgold is seedless and is promoted as a clean tree with nice golden fall colour. Its strong straight stem with a natural central leader and strong branches that angle to 45 degrees make this ash a personal favourite. It doesn’t grow quite as fast as Green Ash, so it requires less pruning and staking when young.

Malus x profusion ‘Purple Wave’
Purple Wave crab apple
Height: 6 m
Zone: 4
Aptly named for its deep purple leaves and unique wavy action of the delicate branches, Purple Wave crab apple was found in our nursery in the summer of 1959 as a chance seedling growing under some larger Profusion crabs. We kept this seedling for years before actually deciding to produce this selection on a larger scale. All of the desirable characteristics of its obvious parent, Malus x profusion, are found in this tree.

     Given the right soil conditions, Purple Wave reaches the average height of most crab apples and is resistant to scab and insect infestations. It does take longer to grow into caliper-sized trees as the stem and branches are thin when young. We believe this tree will mature at 6 m high and 5 to 6 m wide. It can be budded on E.M. 26 rootstock for a dwarfing effect. This will effectively reduce its size by approximately 50 per cent, making it ideal for the small garden. This tree is completely hardy in Zone 4. In May, Purple Wave produces an abundance of deep rosy-red flowers, followed by small red fruit. The leaves hold their deep purple colour throughout the growing season, turning a bronze-yellow in October. There are a number of “Canadian Introduced” crabs available to the trade, many of which are excellent varieties. ‘Purple Wave’ is one of these and would rate eight on the scale of one to 10.

Metasequoia glyptostroboides
Dawn redwood
Height: 25 m
Width: 7 m
Zone: 5
Although this tree is slowly gaining acceptance, it is still one of the least known deciduous conifers. Perhaps this is due to the erroneous belief that it is not very hardy. Michael A. Dirr writes: “This tree was thought to be extinct when it was rediscovered in China in 1941. Seeds were gathered and distributed to the delight of plant lovers around the world. It is believed to be a very ancient tree and is easily reproduced from seed.” Dawn redwood is a nice, dense, pyramidal tree with bright green foliage that drops its needles in the fall, like the larch. It loves full sun and well-drained acidic soil. When mature, it will easily reach 25 m in height and 7 m in width. Fall colour is orange-brown.

     This tree is rated for Zone 5, so look at the vast area in Ontario alone where it can be successfully planted. One property hosted the perfect setting for this tree — a winding driveway in which the owners had lined both sides of the driveway with these majestic specimens, strategically placing them between antique-style lanterns that lit the way. Talk about estate landscaping — a real credit to the landscape architect and owner. You can plant single specimens just as effectively. Be sure to allow for adequate space as the dawn redwood is recommended for parks and open spaces.

Pinus leucodermis var. ‘Heldrichii’
Bosnian pine (slow form)
Zone: 5
Even though some pine varieties have been subject to some ‘bad press’ in the last few years due to oubreaks of Diplodia Blight and Pine Shoot Beetle, pines are still planted in large numbers in many parts of this country. One pine, which has escaped the bad press, is the Bosnian pine (Pinus leucodermis var. ‘Heldrichii’). The question is if this is because the Bosnian pine is free of disease or because people are unaware of its existence. Again, our desire for instant gratification and our reluctance to pay more for plants that cost more to produce has probably put this plant on the back burner of popularity. The growth rate is only 20 to 30 cm annually, so it doesn’t require a master’s in economics to calculate that higher production costs will result in higher wholesale prices. It is important to reject the notion that if it is related to agriculture or horticulture, it has to be cheap.

     This tree is grossly under-rated and needs a few daring architects to specify it in high-profile jobs. Cities and botanical gardens also need to plant some in prominent places so the general public can become acquainted with this marvelous pine as they hurry along to work or stroll along on a summer evening. I refer to future jobs, as inventory is almost non-existent for this particular pine. Growers will produce the Bosnian pine if the demand is there. It is a very gratifying plant to behold and it needs very little pruning or “after care.” Stiff dark green needles are held in brush-like clusters, which will persist for five to six years. Exceptional features such as salt-tolerance and slow growth make this pine a good choice for seaside plantings and municipalities. It is also easy to transplant and is hardy to Zone 5. There is a faster growing form of Pinus leucodermis available, but the slow form is my pick.