Poa bulbosa
bulbous bluegrass
Europe, North Africa, and western Asia
Overview
Poa bulbosa is a tufted cool-season perennial grass 4-16 in (10-40 cm) tall, set apart by a swollen, bulb-like base at each shoot that stores food and survives summer dormancy. The narrow leaf blades are 0.04-0.1 in (1-3 mm) wide, soft, and gray-green, drying off in early summer. Rather than relying on seed, the plant usually reproduces by bulbils: the spikelets in the panicle change into small leafy bulblets that drop and root, a habit called proliferous or viviparous. The panicle is 1-4 in (2.5-10 cm) long, narrow, and tinged green to purple. Growth starts in fall, continues through winter where mild, and finishes by late spring, after which the grass goes dormant and brown until the next cool season. Native to Europe, North Africa, and western Asia, it has naturalized widely across North America in lawns, rangeland, and disturbed ground, where it is often treated as a weed. It tolerates poor, dry, compacted soil that limits other grasses. Its summer dormancy leaves bare brown patches, a limitation in lawns kept green through the heat.
Native Range
Native to Europe, North Africa, and western and central Asia. It has been introduced across North America and much of the temperate world, naturalizing in lawns, pastures, rangeland, and disturbed ground, where it spreads by bulbils.Suggested Uses
Sometimes used for low-water erosion cover and early-season range forage on poor, dry soil. More often managed as a weed of lawns and rangeland, since the bulbils spread it readily and summer dormancy breaks up turf.How to Identify
Appearance
Size & Dimensions
Height4" - 1'4"
Width/Spread4" - 10"
Reaches mature size in approximately 2 years
Colors
Bloom Information
Forms its bulbil-bearing panicles in spring, usually April to June, in place of ordinary flowering. The spikelets become leafy bulblets that drop and root. True seed is set only rarely.
Detailed Descriptions
Flower Description
green to purpleFoliage Description
gray-greenGrowing Conditions
Sun Requirements
Requires 4-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight