Cultivation Essentials and Planting Management Techniques for Annual Bluegrass

Annual bluegrass (Latin scientific name: Poa annua L.), also known as: small green grass, chickweed grass, cold grass, etc.; an annual or winter annual grass. Culms erect or decumbent, soft in texture, 7-30 cm tall, entirely smooth and hairless. Leaf sheaths slightly compressed, closed below the middle; ligule 1-3(-5) mm long, rounded at the tip. It grows on roadsides, grasslands, field ditches, or shaded waste slopes in plains and hills, at an altitude of 100-4800 m. It is distributed in all provinces of northern and southern China, as well as in Europe, Asia, and North America. It is a globally widespread weed that requires strict management and control.

Morphological Characteristics of Annual Bluegrass

An annual or winter annual grass. Culms erect or decumbent, soft in texture, 6-30 cm tall, entirely smooth and hairless. Leaf sheaths slightly compressed, closed below the middle; ligule 1-3(-5) mm long, rounded at the tip; leaf blades flat or folded, 2-12 cm long, 1-4 mm wide, soft in texture, often with transverse veins, the apex acute and boat-shaped, margins slightly rough. Panicle broadly ovate, 3-7 cm long, spreading; branches 1-3 per node, smooth; spikelets ovate, containing 3-5 florets, 3-6 mm long, green; glumes thin in texture, with broad membranous margins, apex obtuse, the first glume lanceolate, 1.5-2(-3) mm long, 1-veined, the second glume 2-3(-4) mm long, 3-veined; lemma ovate, with broad membranous apex and margins, distinctly 5-veined, the keel and marginal veins with soft hairs in the lower part, the intermediate veins with soft hairs near the base, callus without woolly hairs, the first lemma 3-4 mm long; palea nearly as long as the lemma, its two keels densely covered with silky hairs; anthers yellow, 0.6-0.8 mm long. Caryopsis spindle-shaped, about 2 mm long. Flowering period April-May, fruiting period June-July. Chromosome number 2n=14, 28 (Litardiere 1938, Tateoka 1985a, Tutin 1954.).

How to cultivate annual bluegrass well?

For grassland use, it can be drilled or broadcast. Because the seeds are extremely small, the soil must be particularly finely prepared before sowing; after sowing, the soil should be rolled and kept moist. Seed rate per hectare is 7.5-12.0 kg. Control the sowing depth to 1-2 cm to ensure the germination rate. Row spacing 30 cm. Mixed sowing with white clover and bird's-foot trefoil can improve grass yield and quality and regulate the grass supply season, because bird's-foot trefoil grows vigorously in summer. The sowing time should be adapted to local conditions. In warm regions, it can be sown in spring, summer, or autumn, with autumn sowing being most suitable; spring sowing should be early to prepare for overwintering through summer and to avoid competition with weeds; in high-cold regions, spring sowing is in April-May and autumn sowing in July. For lawn seedling raising, sow 105-120 kg per hectare; for direct seeding, sow 150-450 kg per hectare. It is sensitive to nitrogen fertilizer. Applying nitrogen fertilizer in spring can advance the grazing period, generally by 11 days. Applying nitrogen fertilizer can increase the proportion of annual bluegrass and control the proportion of leguminous grasses. When mixed-sown with leguminous forages, the leguminous forages will degrade and need to be resown. However, annual bluegrass can be used continuously and can recover quickly even after heavy grazing. If complete fertilizer is applied every year, the grassland can be maintained indefinitely. Sowing note: to ensure even sowing, divide the seeds according to the predetermined sowing rate into the number of divided plots, sow plot by plot, and after sowing, gently rake the seeds into the soil with a nail harrow; the covering soil should be shallow without exposing the seeds, and must never be too deep. After sowing, gently roll the soil with a roller to ensure close contact between the seeds and the soil. Pest and disease control: common diseases of this grass include leaf spot, rhizome rot, rust, fungal smut, ergot, and anthracnose. To resist these diseases, breeders have carried out targeted disease-resistance breeding work. Pest types: common insect pests include Japanese beetle, annual bluegrass weevil, and sod webworm, and Swedish frit fly.