Pinnate tansymustard

Descurainia pinnata

This biennial or annual plant is ½–2' tall. It branches sparingly and is more or less erect. The round stems are covered with short glandular hairs. Young plants consist of a low rosette of basal leaves spanning 4-8" across, from which there develops during the spring a flowering stalk with alternate leaves. These cauline leaves are up to 8" long and 4" across. They are double or triple pinnately lobed and glabrous or slightly pubescent. The narrow lobes are oblong to oblanceolate, providing the cauline leaves with a fern-like appearance; the lobes become more narrow in the upper cauline leaves. The basal leaves are quite similar to the lower and middle cauline leaves in appearance. The foliage of Tansy Mustard is usually some shade of green. The petioles of the leaves are rather long, although they become progressively shorter as the cauline leaves ascend the stems.

Plant Protection Products