Italian ryegrass (Lolium perenne L. spp. multiflorum (Lam.) Husnot) is generally annual or biennial in longevity, and can provide short-term high yields of high-quality forage. The Westerwold types do not have a vernalization (cold temperature) requirement for flowering, so they will head out throughout the seeding year and usually complete their life cycle by late summer when planted in the spring. The types known in the industry as true Italian ryegrass varieties have a vernalization requirement for flowering, so they will not head out until the second year. They usually grow through the second year and sometimes into the third year.
Italian ryegrass can be planted in April or in August through mid-September. The late-summer to earlyautumn seedings can be made after wheat or corn silage and may produce enough forage for grazing by November if rainfall is sufficient during the fall. Latesummer to autumn plantings survive the Ohio winters (except for the occasional severe winter) and produce forage the next spring and into mid-summer. The Italian ryegrass varieties can differ greatly in winter hardiness, so consult your seed dealer about winter survival in Ohio. Italian ryegrass varieties have produced total forage yields ranging from 3.5 to 6.7 tons of dry matter from a harvest in early November to the last harvest in July of the following year.
Establishment and management of Italian ryegrass is similar to the perennial cool-season grasses, including fertilization and harvest and grazing management. This species can be planted no-till and has vigorous seedling growth. This species can be difficult to cut with a sickle bar mower, but disk mowers handle it very well. For optimal yield and nutritive value, harvest or graze it in the boot stage before heading.
When establishing Italian ryegrass after corn silage in early autumn, be aware of the potential for nitrogen carryover in the Italian ryegrass in the autumn growth, especially following a corn crop during a dry summer. Nitrates can accumulate to toxic levels to animals in the autumn growth of Italian ryegrass. If there is potential of high nitrogen carryover, it would be prudent to test the forage for nitrate content before harvesting or grazing it.