Perennial ryegrass - aftermath heading

Aftermath heading (AMH) is the second seeding of ryegrass, following the main spring seeding, which decreases summer pasture quality.
AMH is a particular problem of old ecotype ryegrasses in drier areas of NZ, which produce large amounts of seedhead through both spring and summer.
Modern varieties have much less AMH, and generally later heading cultivars produce the least. Trojan and Bealey show good summer quality, with low levels of AMH.