Native. Perennial. Propagates by seeds and by rootstocks. Time of bloom: April to May. Seed-time: Beginning of June. Range: Newfoundland to Alaska, southward to Pennsylvania and the shores of the Great Lakes, Colorado, and Oregon. Also native to northern Europe and Asia. Habitat: Prairies; moist meadows.
The name of "Quack" or "Sweet Quack," which western farmers have given this grass is confusing, for the true Quack-grass flowers in June and its matted "couch" of rootstocks is near the surface, while Vanilla-grass flowers in early spring and its rootstocks are deep in the soil. The whole plant has an odor much resembling the Vanilla bean, most lasting if plucked while the plant is in flower. In northern Europe it is strewn before churches, the trampling feet of the congregation causing it to yield its fragrance, and this custom has given it the name of Holy-grass. The Indians of the Northwest make baskets and mats of it; the perfume has a tendency to produce sleep, and pillows are stuffed with it; but as hay or forage it has no value.
Culms one to two feet in height, very slender, erect, simple, smooth. Leaves of the flowering stalks very short, lance-shaped, smooth or only slightly roughened; but after seeding the rootstocks send up many barren stalks with long, flat, rough, and deep green leaves whose task is to assimilate and store food for next season's early bloom. The panicles show when the stalks are but a few inches above the ground and grow with them, unfolding very suddenly; they are pyramidal, two to four inches long, the branchlets spreading and drooping when green but stiffening and becoming erect and wiry as the seeds ripen, the glumes turning golden brown tinged with purple. Spikelets one-seeded. (Fig. 14.)
Summer fallowing, with very deep plowing, which will expose and wither the rootstocks. The ripened grass should first be mowed and burned so as to avoid plowing under the long-lived seeds. Or deep plowing in spring when the grass is in flower, and immediately seeding the ground heavily with some grass of quick growth.
Fig. 14. - Vanilla-grass (Hiero-chloe odorata). X 1/4
Shallow plowing or surface cultivation merely stimulates the growth of the grass.