| | Not only are the poplars and elm leaves changing colour, but so are spruce, pine and juniper needles. This natural occurrence happens every fall as the oldest needles on the evergreen change colour and will eventually fall off.
Conifer foliage, on the inside closest to the trunk, turns yellow or gold, then brown and eventually falls off. Usually this process goes unnoticed because it is gradual, but sometimes many needles will discolour all at once. This can be very alarming because it looks like the tree is dying.
Autumn needle shed is probably the most noticeable in pines. Pine hold their needles for three to four years, while spruce and fir will hold their needles longer. Pine needles grow on the branch in bundles or groups of two, three or five. Spruce needles grow singly, while cedars and some junipers have scale-like leaves covering branchlets instead of needles. When pine shed those inner needles, they drop the bundles, spruce drop single needles, (not necessarily the oldest needles) and the other two conifers drop entire branchlets.
Stress to the plant caused by drought, poorly drained soils, transplant shock or spider mites, can cause it to drop more needles than normal. Even after a stressful winter, some needles can be dropped in the spring.
Evergreens grow at the tips of the branches so, once lost, these inner needles will not be replaced. However, because these trees put on new growth at the tips, the area of lost needles will not be noticeable next spring.
Although needle shed is a regular occurrence, keeping evergreens as healthy as possible with good watering practices and insect control can lessen the amount of needles lost. Remember to water evergreens well at the end of September or October. This will help prevent damage to the root systems during the winter.
Local garden centres can provide information for gardeners. Also, information on yard, garden turf and shrub and tree care is included in the Alberta Agriculture publication, Alberta Yards and Gardens: What to Grow. This publication contains information to help Albertans successfully grow ornamental trees and shrubs, small fruits and berries, flowers, vegetables, herbs and even water plants. To order this publication, call 1-800-292-5697 or purchase on-line. |
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