This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Introduced. Annual and winter annual. Propagates by seeds.
Time of bloom: Late June to September.
Seed-time: August to October.
Range: Ontario and Manitoba, Minnesota and the Dakotas. Appearing locally in other states and provinces.
Habitat: Grain and flax fields; waste places and along railways.
Brought to this country in flax seed from Europe about 1892, this weed has since spread through all the grain-growing section of the Northwest and bids fair to be still more widely known. Autumn plants send down a main root with many branching rootlets, and form a tuft of thick, smooth leaves, three to six inches long, broadly oval, rounded at tip and tapering toward the base, the edges entire, and the surface covered with a bloom like a cabbage; in fact the
Fig. 132. - Sand Rocket (Diplotaxis muralis). X 1/3 young plants resemble cabbage. In the second season the fruiting stalk appears, one to four feet tall, slender but stiff and erect, becoming hard as wire when mature; stem leaves oblong, rather thick, also smooth and glaucous, shaped like a rabbit's ears and clasping the stem by two rounded auricles at the base. These succulent leaves, particularly on young autumn plants, are crisp and tender and make good salad and greens; they absorb most of the food and moisture of the soil, and the accompanying crop does not usually amount to much where the weed is very plentiful. Flowers cream-white and only about a quarter-inch broad. But the pods that follow on the elongating stalk are about four inches long when mature, slim, smooth, and square, each one containing about fifty brown seeds, rounded oblong in shape, very mucilaginous when wet, which causes them to stick to the feet of animals, to a boot-sole, or to a wagon wheel, and helps in their distribution. (Fig. 133.)
Sow clean seed. If the infestation is new, hoe or spud out every autumn plant and hand-pull every flowering stalk in its first bloom; and if pods have formed, burn them, lest they ripen on the stalks. The smooth, waxy surface of the plant sheds all liquids like a duck's back and sprays cannot harm it. Drag out spring seedlings with a weeding harrow and disk off the autumn plants. In every case prevent seeding if possible.