Summer grass is an unsightly grassy weed can spread rapidly. If the weed is left to flower and set seed, the seed can lay dormant for several years and be a nuisance for years to come. Going by the scientific name ‘Digitaria sanguinalis’ it is commonly termed summergrass, but sometimes called hairy or purple crabgrass.
Symptoms are generally evident from Autumn to Spring under favourable conditions. Fusarium survives through the spring and summer as spores and mycelium in the thatch or soil when temperatures are above 16°C or when it is dry. Under cool, wet weather, spores may germinate or mycelium may grow from thatch or soil and infect leaves within the turf canopy
This annual grassy weed is tufted and mat-forming and can inhabit a wide range of soils, although its natural habitat is sandy soil and loams. Summergrass can grow to 30 cm tall and spread to 1m wide if left unmown. Culms (stems) are slender, ascending from a decumbent base. The relatively wide leaves which can be greater than 5 cm long are soft and hairy on the underside of the foliage; the sheaths are also hairy and the ligules are papery to the touch. The stems often have a red to purple tinge to them. The stolons of the plants root down at nodes, which can dramatically increase the area, the weed encompasses. Inflorescence is more or less terminal, to 15 cm, slender, spreading, 2 to 10 per inflorescence. Summer grass flowers in summer and autumn when it seeds profusely. The seed can remain dormant in the soil for several years before germinating. Summer grass has shallow fibrous roots.
A widely distributed weed, summergrass is found in tropical, subtropical and temperate regions.
Summer grass is an annual grass weed propagated by seed. Seeds develop in late summer and autumn thus ensuring an abundant infestation during seasons thereafter, unless a pre-emergent program is introduced. When temperatures are optimal, summer grass emerges 2 to 3 weeks earlier than crowsfoot (Eleusine indica).Download PDF