Probably no group of ornamental trees is more widely used or better known than the birches. All species and cultivars are truly distinctive trees and possess many interesting features. Most outstanding is the bark, which ranges from pure white of the paper or canoe birch to light mahogany of the river birch. Their pendulous catkins are one of the first harbingers of spring when they start to elongate, and the autumn color of the foliage is always a clear and brilliant yellow.
Because the birches used for landscaping are small to medium in size, they are desirable for small properties and can be grown in spaces where other larger trees would not fit. They do not cast dense shade due to the small leaves, and therefore do not seriously limit the types of plants that can be grown nearby or under them. Birches do not compete with grass, nor do they create a serious leaf disposal problem in autumn.
It is common to see clumps of three or four birches growing together when used in the landscape to give the effect of a multiple-stemmed tree. Because very few other trees are used in this way, it does give a pleasing change from the more common, single-trunk tree.
The winter effect of the white birches is outstanding. It becomes particularly so when there is an evergreen background such as pine or spruce to accentuate the white bark. For special effects use birches as a background for plantings of red-stemmed dogwoods like Cornus alba 'Sibirica.'
In general, birches are somewhat difficult to transplant. Therefore, to ensure success they should be moved, balled and burlapped in spring. Pruning can be done at any time of the year except the early spring because they will "bleed" profusely.
Birches are susceptible to two serious insect pests, which if not properly controlled can mar their effective use as ornamentals. The first is the bronze birch borer, a small grub about 1/2 to 1 inch long that feeds just under the bark. If present in sufficient numbers, it can kill the tree. To prevent damage by this insect, contact the county Extension office for recommendations and treat with the proper insecticide.
The other insect, the birch leaf miner, eats its way between the upper and lower epidermis of the leaf. The entire tree may turn brown during severe infestations. Spray with either Malathion, Dursban, Sevin or Meta-Systox-R in mid-May and again in late June.
The river birch is pyramidal while young with reddish-brown or mahogany bark that exfoliates or peels off in thin layers, producing a slightly shaggy appearance. This birch can be used in wet locations where other trees may not be satisfactory, although it does not require wet soils. Because river birch is somewhat more resistant to the birch borer than other species, is suitable for moist areas and has exfoliating bark, it deserves to be planted more than it is. Heritage is a superior cultivar.
Paper birch has the whitest, smoothest bark of all the birches. Its branches are white and the leaves, which turn golden yellow in autumn, are slightly glossy. Paper birch is the most popular of the birches for ornamental use and is less susceptible to severe attacks of the birch borer than European birch.
The European birch is pyramidal in habit with white trunk and older branches and lateral branches that are slightly pendulous. The leaves are smaller and more triangular than paper birch. It is a short-lived tree because it is susceptible to attack by the birch borer. It is often attacked high on the trunk and the whole top is killed.
A number of cultivars of Betula pendula are available, including:
The trunk is white. The most readily available varieties will be:
NOTE: Disclaimer - This publication may contain pesticide recommendations that are subject to change at any time. These recommendations are provided only as a guide. It is always the pesticide applicator's responsibility, by law, to read and follow all current label directions for the specific pesticide being used. Due to constantly changing labels and product registrations, some of the recommendations given in this writing may no longer be legal by the time you read them. If any information in these recommendations disagrees with the label, the recommendation must be disregarded. No endorsement is intended for products mentioned, nor is criticism meant for products not mentioned. The author and Ohio State University Extension assume no liability resulting from the use of these recommendations.
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Keith L. Smith, Associate Vice President for Ag. Adm. and Director, OSU Extension.
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