Warm-Season Grasses for Hay and Pasture

Switchgrass, Indiangrass, and big bluestem are warmseason grasses that are a suitable alternative for summer pasture in Iowa. Their advantage over cool-season grasses such as bluegrass, bromegrass, and orchardgrass is their ability to produce during midsummer. These warm-season perennial grasses start growing in late spring as air and soil temperatures increase. Leaf growth often occurs in early May in southern Iowa and by mid-May in northern Iowa. Growth may start slightly earlier on south-facing slopes. Greatest growth occurs from June through September. Growth slows in the autumn and ceases with the first killing frost. Pasture efficiency may be improved by converting one-fourth to one-third of the cool-season grass pasture acreage to a warm-season grass to be used in conjunction with cool-season grasses. Cool-season grasses can be grazed in the early and late parts of the grazing season, with the warm-season grasses grazed during midsummer. This scheme provides a larger and more uniform supply of forage, and greater seasonal animal gains can be expected. Furthermore, the cool-season grasses can be given a rest during midsummer. This improves their vigor and provides a greater supply of forage for late-summer and fall grazing.