Tiller (botany)

A tiller is a stem produced at the base of grass plants. Tillers are segmented, each segment possessing its own two-part leaf. They are involved in vegetative propagation. Tillering is a property possessed by many species in the family Poaceae which enables them to produce multiple stems (tillers) starting from the initial single seedling. This ensures the formation of dense tufts and multiple seed heads.

"Tillering" refers to the production of tillers. Tillering rates are heavily influenced by soil water status. When soil moisture is low, grasses tend to develop more sparse and deep root systems (as opposed to dense, lateral systems). Thus tillering is inhibited; the lateral nature of tillering is not supported by lateral root growth in dry soils.