Seedhead production varies from species to species and seasonally within species. Tall fescue makes a good example. Most spring growth tillers, in response to temperature and day length, produce seedheads. Fall growth tillers generally remain vegetative. In some cases there are also varietal differences in seedhead production within a species, as common verses Coastal bermudagrass.
New tillers originate from basal buds, a form of specialized plant tissue.
If growing points are removed by grazing or cutting, no more tillers are produced. Individual tillers are relatively short-lived, even on the perennial forage plants. Individual tillers often live for only 5 to 10 weeks, then die. The tiller grows, producing leaves, then turns reproductive, produces a seedhead, matures the seed, then the tiller dies. A bermudagrass, switchgrass, or tall fescue tiller does the same thing, with the exception that some of the tillers die without becoming reproductive.