Dame's Rocket/Common Milkweed

County Agent News

Dan Folske

October 17, 2011

Dame’s Rocket

                Dame’s rocket is an escaped ornamental from Eurasia and most often found along roads, streams, near woods and in thickets. The first introductions to North America began in the 1660s and the plant is now considered naturalized. However, infestations have been increasing rapidly in the north-central states. Dame’s rocket aggressively competes with native species and has been listed as a noxious weed by the USDA. I have also seen this plant expanding in Burke County and can be found on many vacant lots and throughout many vacant farmsteads.

Dame’s rocket is a biennial or occasionally short-term perennial herb in the mustard family. The plant resembles phlox, but has four petals, not five. The plant grows 2 to 4 feet tall; the stems are erect and often branched. Leaves are alternate, lanceolate, sharply toothed and pubescent. Dame’s rocket flowers are found from early May through June, fragrant and generally purple but occasionally pink or white. Seeds are produced in long pods typical of the mustard family. Dame’s rocket overwinters as a rosette. I often get calls from people asking if it is Purple Loosestrife, however Purple Loosestrife flowers have 5 to 7 petals.

Dame’s Rocket is easily controlled with MCPA or 2,4-D.

Common Milkweed

Common Milkweed is often a source of controversy. It is native to North America and is the primary food source for Monarch Butterflies. While generally not a problem in range and pasture land it can become a problem in cropland under reduced tillage systems because of its extensive root system and tolerance to most common herbicides.

As the common name implies, the plants contain a thick, white, milky latex throughout the plant. Flowers are arranged in clusters at the top of the plant and are pink to white. Common Milkweed grows to 2 to 4 feet tall and has large opposite leaves 3 to 5 inches wide and 6 to 10 inches long, which are covered with fine pubescence. These perennial plants have shallow fibrous roots. Milkweed grows over a wide range of soil moisture conditions, but can become dense under medium or high moisture levels. Seed pods are 3 to 5 inches long and contain dozens of flat, reddish-brown seeds with tufts of hairs that allow the seed to travel long distances in the wind. An established market exists for milkweed seed floss as a nonallergenic fill to replace imported duck and goose down in comforters and for seed sales in prairie restorations and butterfly  gardens. Most commercial milkweed supplies still are collected from the wild.

Although some producers have asked to have Milkweed placed on the state’s  noxious weed list that has not been done because of its status as a native plant. Because of its relationship with the Monarch Butterfly, control is generally not recommended unless it is invading cropland.