The Homeowners Column

The Homeowners Column

Identifying Cold-Loving Winter Annuals

Photo of Sandra Mason

Sandra Mason
State Master Gardener Coordinator
slmason@illinois.edu

In winter I often wander my cold-cleared garden. Vivid visions of produce past dance in my head. Sometimes in the recesses of the beds or tucked neatly along the path I am surprised by the sight of luxuriantly green leaves of presumably cold confused plants. We typically think seeds germinate only in the spring. However some seeds purposefully germinate in the fall and are happily hanging out through the winter. As temperatures rise in early spring they perform the perfect jump start in gardens and on gardeners.

These plants are commonly called winter annuals. The young plants are very cold hardy and often stay green late in the season. The same plants then flower in early spring and form seeds well before we have located our garden boots. Winter annuals commonly germinate in bare soil areas and where the soil has been disturbed through garden tilling, dog digging, or kid running in lawns, gardens, and fields.

A common winter annual, Henbit (Lamium amplexicaule) is often confused with Creeping Charlie, Glechoma hederacea. Both have square stems and are in the mint family with small tubular flowers. Henbit flowers are more in the purple/lavender color range and are clustered at stem tips with a "Mamie Eisenhower" collar of clasping leaves below the flower cluster. Creeping Charlie flowers are more in the blue range without the clasping leaves. Both plants have round shaped, scalloped leaves and are often considered weeds.

A couple differences between Henbit and Creeping Charlie include the life span and flowering time and, therefore, control measures. Henbit is a winter annual and Creeping Charlie is a perennial. The original Creeping Charlie plants come back every year and often stay green well into winter. Henbit has to start from seed each year. Henbit as a winter annual blooms very early in the spring and well before Creeping Charlie blooms. Around here you will often see whole farm fields of purple flowered Henbit early in the season.

Common Chickweed, Stellaria media, is another winter annual. It is a low spreading plant that can grow 4-12 inches tall. It often grows in the shade of trees and shrubs or the north side of buildings. Chickweed has light green, small and ovate shaped leaves with pointed tips. The flowers are small, white with five deeply notched petals. The stems are creeping and often root at the leaf nodes.

For foragers winter annuals are a tasty treat since they are green when little else is. Chickweed salad comes to mind. Whether your goal is slathering with butter or slaughtering with a hoe, accurate plant identification is crucial. Check your library for weed identification books or bring samples to your local U of I Extension office.

UI Extension has a new publication - Identifying Weeds in Midwestern Turf and Landscapes C1397 for $8.50. It is a handy spiral bound booklet with plenty of pictures and descriptions. Order through UI PubsPlus at https://pubsplus.illinois.edu/ or by phone PH: 800-345-6087 or 217-333-2007. A perfect holiday gift. Ok maybe not perfect but include an offer of weeding time of said identified weed and it will surely be a hit.

Control of winter annual weeds includes removing plants now by hoeing or hand pulling. Broadleaf herbicides can also be effective if used while the weed is actively growing now or before the weed flowers in early spring. Realize herbicides are not effective at cold temperatures. Be sure to read and follow all label directions.

Once annuals flower and form seeds, controlling the original plants does nothing for future control but does provide some relief through revenge. Beat 'em or eat 'em winter annuals are green and growing when other plants are dead and decomposing.

Join us for Master Gardener training program. Apply online http://web.extension.illinois.edu/cfiv/ Questions? Contact me at slmason@illinois.edu or 217.333.7672.

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