TREES AND THE ENVIRONMENT
We have all become very aware of the damage from pollution that threatens our environment. The burning of fossil fuels in home, industry and automobiles is affecting the earth’s atmosphere and the air that we breathe.
Our smaller urban gardens may not accommodate the traditional large leafy shade trees much favoured by previous generations, such as maple and oak. However, this does not preclude us from contributing to a better environment. Many other smaller trees are just as valuable in the uptake of carbon dioxide and the production of life essential oxygen. Even a small property can afford space for quite a few such trees.
Most of the original hardwood forest was cleared for essential food producing farmland and it is our duty to replace these trees as much as possible. An ‘urban forest’ is entirely possible and we would further encourage that this ‘forest’ be quite diverse. The stately elms that were lost to ‘Dutch Elm Disease’ were prone to attack, mainly because of the large number of trees that were planted in close proximity.
We are all inclined to be fairly timid in our selection of plant material, choosing familiar names such as Crimson King Maple or White Birch. However, a wider selection is now available and we encourage you to be adventuresome and learn more about these different varieties. Note the many trees that are tough, durable, attractive and perfectly suitable for our environment. Maidenhair Tree (Ginkgo biloba) is an ancient tree that is a true survivor and tolerant of city conditions.
Ivory Silk Lilac (Syringa reticulata) is a lovely smaller tree with large fragrant white flowers in summer and glossy green leaves. Ornamental Pears have clean white spring blossoms and glossy foliage that colours nicely in fall and persists on the tree well into winter.
Mountain Ash (Sorbus aucuparia) for example, is commonly planted but there are many other varieties, many with superior qualities, such as Russian, Showy, Cardinal Royal and more.
You can develop not only a pleasing garden on your own property but also add greatly to the diversity of trees in your neighbourhood by an intelligent and astute choice.
SHADE TREES
The original function of shade trees in residential plantings was for shade; to keep the home cool in summer and once the leaves had fallen, to allow sunshine into the house in winter. Today with air conditioning and efficient furnaces, the utilitarian use of shade trees is less important, although they can lessen the cost of using such equipment. The choice of trees and their placement in the landscape is now guided somewhat more by matters of taste and design.
Flowering trees offer many of the advantages of shade trees plus the added benefit of beautiful colour and fragrance. The brilliant pink, white or red blossoms of a Crab Apple or the delicate pink of a Flowering Cherry in bloom can add colour and life to your yard.
FERTILIZING TREES
Fertilizer ‘spikes’ can be hammered into the soil under the tree following the directions on the label. Fertilizer Tree Spikes for shade trees, evergreens and fruit trees are very effective and easy to use.
Liquid fertilizer can be applied through a root-feeding device attached to the garden hose. This is also a good way to deep-water the tree roots.
Calculate the amount of dry fertilizer required and apply it to the surface uniformly over the tree root zone and then water the area well to move the nutrients into the soil. The zone of actively absorbing roots begins beyond the drip line of the tree and extends one half to two-thirds the distance between the drip line and the trunk. Be careful when applying dry fertilizer to trees that are growing in the lawn - the quantity of fertilizer recommended for the tree may injure the grass under the tree.
PRUNING TREES
Generally, the best time to prune established deciduous trees is in summer, especially if cuts over 4 cm. in diameter must be made. At this time the cambium tissue is active and healing can immediately take place. If plants are pruned during the winter months, the wound is left exposed to disease or fungi and bleeding can take place for a longer period of time. Trees that bleed profusely are Maple, Walnut, Birch, Magnolia, Elm and Mulberry.
As the tree grows, routine pruning will ensure the natural symmetrical shape of the tree. As a general rule, keep the interior of trees open to allow good air circulation and remove dead, diseased, broken and interfering branches.
For more information see our Green Thumb Guide to Pruning GT 121B.
FLOWERING SHRUBS – COLOUR IN YOUR GARDEN
The Ontario countryside in the fall is a spectacularly colourful landscape that we all admire and enjoy. Many of us make special trips to view the brilliant colours of Maples and waysides adorned with Goldenrod and Asters. But where is the colour in our own garden?
In planning our gardens, we very logically begin at the beginning. Spring flowering bulbs followed by early flowering shrubs such as Flowering Almond, Japanese Cherries and others. We realize that these flower only for a short time and look for other shrubs and trees for continuing colour throughout the summer. Deutzia, Mockorange, Weigela and, of course, Roses.
Soon, our garden space is fully planted and only in September do we realize that we have neglected to include the late flowering shrubs and those with brilliant fall foliage. Burning Bush (Euonymus alatus) is one popular shrub that is widely used but there are many more that can enhance your garden in the fall and extend your season of colour.
When selecting Humber shrubs, think of the following:
- Approximate ultimate height for each shrub is given. Since actual maximum height depends on many factors, the heights shown are guidelines only.
- Growth habit
- Flower and fruit produced
- Foliage colour – summer and fall: foliage size and texture
- Light and soil requirements
- Remember HOW TO PLANT instructions (on the back of your invoice).
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EVERGREENS
The most popular of all garden plants, they keep their form and colour twelve months of the year and are effective right from the moment of planting.
Evergreens are available in a wide choice of colour, size and form. Whether your garden is large or small, in sun or shade, there are evergreens for every situation.
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CEDAR
Pyramidal forms are much used as specimens, wind breaks, screens and hedges. The globular forms are ideal for foundation plantings. Cedars will thrive in sun or partial shade where soil moisture is adequate. Extra watering is needed during dry spells and abundant water should be applied to the roots before freeze-up. Mulching the soil will help to conserve moisture.
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JUNIPER
A hardy and versatile group of evergreens. Humber Nurseries has always made a specialty of Junipers and the majority of our listing are grown on our farm in Caledon East. Available in pyramidal upright form typified by the popular “Mountbatten Juniper” and in low-spreading and semi-upright forms in various shades of green, blue and gold. As a group they prefer sun but some tolerate partial shade.
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SPRUCE
Evergreen conifers that offer a very wide choice of size and form for every garden purpose. The pyramidal forms, particularly those of the bluest colour are very popular as lawn specimens. The many dwarf varieties available in Conical or globular forms are well suited to the smaller garden, foundation plantings and rock gardens.
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PINE
The taller type such as Austrian Pine make excellent specimens as well as windbreaks. Dwarf varieties are most suitable for small gardens and for foundation plantings. The growth rate of pines is easily controlled by removing part of the candle-like new growth in spring.
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YEW
Unsurpassed for their ability to prosper in sun or shade. Upright forms can be formally clipped and the spread of low growing varieties easily contained. Yews are tolerant of city conditions and with their lustrous dark green foliage make superb hedges.
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BOXWOOD
Small shrubs that keep their lustrous green leaves all winter. Valued for their ability to grow in sun or shade. Easily trimmed or clipped into formal shapes for foundation plantings or as a low evergreen hedge. Often used in cemetery plantings and as part of the design in traditional herb gardens and parterres.
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COTONEASTER
Conveniently included with broadleaved evergreens although most are somewhat deciduous in our climate. Their crop of red berries prolongs the garden display and adds colour to the winter garden.
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AZALEAS AND RHODODENDRONS
Perhaps the most beautiful of all spring flowering shrubs. Our selection has been carefully chosen for hardiness in local conditions. They are, however, most particular in their cultural requirements, needing an acidic peaty soil with excellent fast drainage. The evergreen varieties need winter protection from sun and wind and the roots well mulched.
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HOLLIES
The dark blue-green spiny leaves and bright red berries make holly a most valuable evergreen, particularly in the winter garden. The quality of the winter foliage is best retained when the planting is protected from winter sun and wind. In hollies, the sexes are on different plants and at least one male holly must be planted to ensure a crop of berries on the females.
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EUONYMUS
A very valuable and versatile family that retain their foliage through the winter. The foliage can be dark glossy green or variegated in combinations of green and white and green and gold. They can be grown as shrubs or vines, for they will climb using aerial roots. Planted against a house wall adds depth and interest to foundation planting.
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FIRETHORN
Semi-evergreen shrubs with large trusses of white flowers in spring and brilliant orange berries in fall and winter. They lend themselves readily to training and are perhaps at their showiest when trained on a wall.
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 HEDGES
Evergreens such as Cedar, Juniper and Yew make excellent formal hedges. Boxwood, Euonymus and dwarf conifers can be used for low hedges and upright cedars and/or junipers for taller hedges or screens. Deciduous plants that tolerate constant pruning can be equally formal – Privet, Russian Olive, Chinese Elm and Alpine Currant are some good examples. White Cedar is the most popular evergreen for hedging. It is relatively inexpensive and can be maintained at any height required from 1 to 12 meters.
Large evergreens such as Spruce, Pine, Fir and Hemlock are ideal for taller hedges or screens.
For more information see our Green Thumb Guide to Hedges and Screens GT 221 B. |
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