These are easily noticed on annual ryegrass but much less so on perennial ryegrass. Annual ryegrass does not tolerate frequent close mowing. It is best adapted to mowing heights of 2 to 3 inches using a rotary type mower. Annual Ryegrass A cross between annual ryegrass and perennial ryegrass has produced a new species of grass called Lolium hybridum . The intention is to have a grass with better qualities than annual ryegrass, along with the ease of spring transition of the annual ryegrass, as well.
Most varieties are more upright than the perennial ryegrasses and are lighter in color.
Annual and perennial ryegrass varieties should never be mixed together in a seed mixture. The resulting lawn will look very weedy and have differences in color, texture, and result in poor uniformity. Note that hybrid ryegrass is not a mixture of annual and perennial ryegrass, but is a separate grass species by itself. During the fall, bermuda grasses can be over seeded with ryegrass. Both annual, perennial ryegrasses or the hybrid can be used.