Colonial Bentgrass
Agrostis capillaris
Poaceae · grass sedge · introduced
Data Coverage 5 of 6 dimensions
Historically common in western WA lawns, often present as an uninvited but well-adapted component. Naturally suited to the acidic, moist soils of the Puget Sound lowlands. Seed alone at 2 lb/1000 sqft or mix with Chewings fescue (0.5 lb bentgrass + 2.5 lb fescue). Requires more intensive mowing management than other lawn species but rewards with a very fine-textured, dense turf.
Quick Facts
Height
4-12 in (unmowed); mow to 0.375-1 in (western WA)
Spread
Spreads by short stolons; forms a dense, fine-textured mat
Growth Rate
Moderate
Light
Sun to Part Shade
Soil
Moist
Water
Moderate
Hardiness
Zone Zones 4a–8b
Origin
Europe
Phenological Calendar
| Stage | Typical Window |
|---|---|
| Spring green-up BBCH 09 | Feb 1-Feb 28 |
| Active vegetative growth BBCH 21 | Mar 1-Apr 15 |
| Peak spring growth BBCH 39 | Apr 15-Jun 15 |
| Summer stress period BBCH 45 | Jul 1-Aug 31 |
| Fall recovery BBCH 21 | Sep 1-Nov 1 |
| Winter semi-dormancy BBCH 97 | Nov 15-Feb 1 |
Diseases (4)
Pests (1)
Cultivars (1)
''General category''
Colonial bentgrass (A. capillaris) should not be confused with creeping bentgrass (A. stolonifera), which is used on golf greens and requires even more intensive management. Colonial bentgrass is the species historically used in western WA home lawns and is well-adapted to the maritime climate.
Commonly invades other lawn types in western WA due to favorable climate; can be managed as the desired species rather than treated as a weed