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Yellow-bud Hickory (Carya cordiformis) . Shagbark Hickory (Cary ovata)
Ironwood (Ostrya virginiana) Hawthorn (Crataegus mollis).

Winter Buds of Wisconsin Trees


Winter can be long in Wisconsin (even if not particularly cold this year) and many of the traditional summer outdoor recreations get put aside. The above photos are intended to show that there are still opportunities for "winter botany". Many of our native trees and shrubs can be accurately identified in winter with a little practice. The color, shape and size of buds, the number of "bud scales" and other characters are helpful. The four species shown above are Yellow-bud Hickory (Carya cordiformis) upper left, Shagbark Hickory (Cary ovata) upper right, Ironwood (Ostrya virginiana) lower left, and Hawthorn (Crataegus mollis) Lower right. There are also clues to identifying each species in the bark of the trunks or twigs, in the leaf scars left behind when the leaves fall off, or even the growth form of certain species.

The buds of trees contain all that is necessary for the next year's growth. In the spring, the bud scales covering the buds will fold back as the growing tissue inside expands. The twig will grow longer and produce new leaves and possibly flowers, from tiny structures already present in the buds. Here is an example of an opening bud of Shagbark Hickory (Carya ovata), shown above on the upper right. After the summer's growth is finished the twigs will form new buds for the next winter, with the next year's leaves already formed, but very tiny.

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Last updated on April 15, 2014