Forest Preserve District of Cook County, Illinois
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Plant Rosettes
Nature Bulletin No. 662   January 13, 1962
Forest Preserve District of Cook County
John J. Duffy, President
David H. Thompson, Senior Naturalist

PLANT ROSETTES
In winter our landscape is mostly leafless trees silhouetted against the sky, and the dead stalks of wildflowers, weeds and tall grasses -- with or without a blanket of snow. Some snows lie on the ground for only a few days. Others follow one after another and cover the ground with white for weeks at a time. Soon the eye begins to hunger for a glimpse of something green and growing. Then, in sunny spots where the snow has melted or where youngsters have cleared it away, there appear clusters of fresh green leaves pressed tight to the soil.

Whether it is a dandelion in the lawn, a pansy in a flower border, or a thistle in a vacant lot, such a typical leaf cluster -- called a winter rosette -- is a ring of leaves around a short central stem. The leaves are narrow at the base, wider toward the tip, and spread flat on the ground with little or no overlap. This arrangement gives full exposure to sunlight and close contact with the warmer soil beneath. Such plants continue to grow, sometimes faster, sometimes slower, even under snow, throughout winter.

Each kind of plant seems to have a calendar of its own. There is a time for growing tall, a time for flowering, and a time for scattering seed. Among those herbaceous plants that live over from one year to the next -- biennials and perennials -- the winter rosette is especially suited for temperate climates. In its first summer a biennial such as a wild carrot or an evening primrose grows a rosette of leaves from a seed. This lives over winter, shoots up a tall stalk the next summer, blooms, ripens seed, and then the whole plant dies. In many perennials, for example the hollyhock and common plantain, the flower stalk dies as the days grow shorter but the underground parts and a rosette of green basal leaves live on until the following year when, again, they flower and set seed.

In our region the winter rosette habit of growth is scattered through many families of flowering plants and over many types of environment. Almost all of them are viewed in different ways by different people, depending on where they grow and on our personal likes and dislikes. By and large, the majority of them thrive in poor soils and in waste places where they furnish ground cover and aid in breaking up and enriching the soil. With their hardy underground parts they survive fires, floods, trampling and grazing.

The rosettes of dandelion, plantain and buckhorn are merely lawn pests to most people. However, some of us enjoy a mess of dandelion greens in spring. In farmers' pastures, grain fields and hay fields a few of these winter rosettes followed by their tall summer stalks are noxious weeds. Cattle, sheep and horses refuse to eat spiny thistles and teasel, the fuzzy mullein, or the ill-flavored wild carrot also called Queen Anne ' s lace. But, on roadside s, old fields and waste places their bold flowers add welcome color. In autumn, when dead and brown, they are picked for winter bouquets.

Strawberries come from rosettes which are cultivated by the thousands of acres. Smaller in size but full of flavor, ripe wild strawberries abound in the forest preserves each June. The tender leaf clusters of winter cress or yellow rocket make a salad that tastes the same as its near relative, the water cress.

Our wildflower season is ushered in by the blooming of the hepatica, usually before the last snows of spring. Its delicate white, lavender or pale blue flowers on their furry stems push up from a winter rosette of three-lobed liver-colored leaves. On the other hand, the blooming season is closed, often after autumn snows have begun to fly, by the purple flower spikes of a little mint called heal-all which also arise from a ring of basal leaves.


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