Contact(s): Kelly Kearns, 608-267-5066
MADISON -- Throughout Wisconsin the invasive plant known as dame's rocket has started blooming and state invasive species experts are encouraging gardeners to take steps to prevent its spread and to follow rules prohibiting the sale, giveaway or planting of this invasive plant.
Dame's rocket is regulated as a "Restricted Invasive plant" in Wisconsin, making it illegal to buy, sell, give it away or plant it. The flowering plant has spread from garden beds to woodlands and other natural areas. Because of the high number of seeds produced by each plant, dame's rocket can often spread rapidly and out-compete native wildflower populations.
"Many gardeners enjoy having dame's rocket in their garden because it has pretty, aromatic flowers," says Kelly Kearns, invasive plant specialist with the Department of Natural Resources.
"We encourage landowners to control it on their property by pulling the plants from the soil. If you do want to keep dame's rocket in your yards, however, you may do so but please help reduce the spread by removing the flower stalk when the flowers begin fading."
By removing and destroying all seed pods before the seeds start to drop, gardeners can maintain the plants without furthering the spread of an invasive plant species, Kearns says.
Dame's rocket looks very similar to a native garden species, phlox, but there are two simple tricks that gardeners can use to tell these two plants apart: counting petals and examining the leaves. "Dame's rocket has four petals on each flower and phlox has five," Kearns says.
Additionally, phlox has opposite leaves instead of the alternate leaves found on dame's rocket. Like the related garlic mustard, dame's rocket overwinters as a large green rosette, sending up a flowering stalk in the spring. Early spring and late fall are good times to spot and control these rosettes.
Gardeners can also help control the spread of dame's rocket by pulling the plants from the soil, taking care to remove the entire root system to ensure that the plant cannot re-sprout. If the plants have flowers, the removed material can be bagged and sent to a landfill or burned in order to prevent the spread of seeds.
Kearns says that it can take several years to suppress populations due to seeds in the soil that will grow in future years.