Happy in the Cold: Wild Radish

The natural tri-colors of panhandle Florida’s winter are giving way to the soon to be arriving seasonal change. The dominant hues of green, tan and brown represent the evergreens and the deciduous species.

The rainbow shades of brilliant spring will be here in a few weeks, but for now only a few plants offer any variation to the subdued tints. These heralds of the growing season to come have had to work hard during the winter of 2023 with its occasional frosty morns.

For a minority of plants though, the chilly temperatures and short days are the ideal environment to sprout, bloom and grow next year’s seed. Wild radish is one such plant which is currently in bloom.

The distinctive bright green foliage topped by diminutive yellow blooms makes the wild radish easy to spot on road shoulders in north Florida. Their rapid growth pattern makes them appear almost overnight.

Raphanus raphanistrum, the scientific name for wild radish, is a native of Europe’s and Asia’s northern latitudes. This annual flourishes in marginal soils and has spread to most of the world, especially areas with disturbed soils.

The term Raphanus has a Greek origin meaning quickly appearing. This accurately describes the rapid emergence and growth, when the soil temperature falls below 65 degrees and enough moisture is present.

Bloom color of wild radishes can vary. Yellow and white are the most commonly encountered shades, but occasionally lavender is on display.

When first emerging the wild radish’s leaves are kidney shaped and covered with hairs, top, bottom and on the stems. The plant may reach three feet in height, but it will rapidly decline with the advance of warm weather.

Wild radish is a member of the Brassicaceae plant family along with cabbage, turnip, and mustard. Unlike its cultivated relatives, this species is not deliberately grown in gardens or fields.

Wild radish are setting seed now in panhandle Florida. The seed pods do not shatter easily. Instead, they must decay before distributing the seeds.

While usually seen on roadsides, wild radish is one of the most common and problematic pasture weeds in the Florida panhandle. It is found throughout the state and can be a serious pest in other crops including peanuts, corn, and winter vegetables.

Wild radish has a thick fruit pod from which seed do not shatter or easily scatter. The pods in this species must decay before the seed can be released to germinate.

The first true leaves of wild radish are slightly serrated and indented about two to three times as long as wide. As the leaves mature, the serrations will be increasingly jagged and more deeply indented. The stiff hairs remain throughout the plant’s life, continuing the bristly feel and appearance.

With the temperatures and day length increasing, this plant is currently bolting. Bolting is a process in which the regions of the stem between leaves begin to lengthen and a flower stalk forms at the top.

In wild radish, multiple flower heads form on several branches arising from a single flower stalk. In this region the seed pods are beginning to set but are not yet mature.

The most effective way to control wild radish is to prevent it from ever germinating. This may be accomplished by eliminating the plant before it sets seed and by maintaining a dense carpet of grass which may crowd out this weed.

This strategy is highly effective in pastures and lawns which are frequently monitored, but difficult in wild areas or even road shoulders because of this plant’s rapid growth pattern. At least the bright blooms are an unmistakable indicator of an area which may require control.

About the author
Les Harrison

Les Harrison is a longtime resident of north Florida, having attended public schools in three counties. He has a Bachelor Degree from the University of Florida in Journalism and a Master’s of Science from Auburn University in Agricultural Economics. He is the author of more than 2000 newspaper and magazine stories and journal articles. During his career, he held positions in private, government and educational (university level) sectors. He holds the title of Extension Agent Emeritus. He can be reached at harrison.gl@gmail.com.

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