L E A V E S - a mini essay

by Steve Gahbauer, Rouge Valley Foundation

It will soon be that time of the year again when mother nature wields her paintbrush and transforms the leaves of shrubs and deciduous trees into a brilliant palette of fall colours.

Staghorn Sumac and Virginia Creeper are among the first woody plants to turn colour in early autumn. Leaves of the introduced Norway maples become a paler green and many of them are marked with black blotches, characteristic of tar spot. This fungus infects maples but does not affect the trees’ health.

By now, White Ash seeds have ripened and are beginning to fall. The seeds are elongated and have one wing, in contrast to Manitoba maples whose keys have two. Ashes are hardy trees that tolerate a range of soil and moisture conditions. In the Valley we find White Ash, Green Ash and Black Mountain Ash – and in the city also the pretty, deep orange berries-bearing Mountain Ash.

Some of the late summer’s wildflowers still blooming in the Rouge Valley are Jerusalem Artichoke, a tall, yellow sunflower; chicory and asters; thistles and the tri-fold birds’ foot flowers, better known as “butter and eggs” and not to be confused with the still blooming yellow-flowered hop clover.

In swampy areas beside the trail Spotted Jewelweed continues to flower. It’s in the touch-me-not family. When you brush the fat fruit capsules they instantaneously and forcefully eject their seeds via a coiled strand that acts like a loaded spring. The juicy leaves are a natural remedy for stings and itches when you rub them over the irritated area.

But back to the Staghorn Sumac. It is native to Eastern Canada and has alternate compound leaves that turn to vibrant yellow, red and purple in the fall before they drop. Sumacs belong to a subgroup of the cashew family. They grow abundantly in the Valley on disturbed and well-drained sites in almost any soil, sprout energetically, and are among the pioneer shrubs, colonizing “empty” areas and giving shade, shelter and food to a variety of wildlife.

Sumacs provide an abundant food source in autumn, and even more so in winter when deep snow covers the ground. Then they offer nutritious plant proteins and sugars for deer, rabbits, and a variety of birds, including Black-capped Chickadees, thrushes, Blue Jays, Red-eyed Vireos, and Northern Cardinals. The dark-red seed cones on top of the velvety spikes can be used to make a fine lemonade or tea. The taste is a bit tart, but the drinks are high in Vitamin A.

Other trees to watch in the Valley as they start changing leaf colour are the Bigleaf maples, Shagbark Hickory, Basswood, and the Red and White oaks. Enjoy nature’s display ! S.G.

Sources: Canadian Wildlife Federation, Nature Canada, Todmorden Mills Wildflower Preserve, Arboretum America, and personal field notes.