Colonial bentgrass

What is colonial bentgrass?

Colonial bentgrass (Agrostis capillaris, formerly Agrostis tenuis) is a cool-season bentgrass with very fine blades. It grows dense and upright and makes a soft turf. Michigan State also calls it brown top.

Colonial bentgrass grass likes cool, humid weather and can take some shade. Michigan State notes it resists dollar spot better than creeping bentgrass but is very susceptible to brown patch.

It is a moderate- to high-maintenance grass. UC IPM says it needs frequent watering, aeration, dethatching, a fairly high level of fertilizer and frequent close mowing. It handles heat, drought, salt and traffic poorly.

How to identify colonial bentgrass

Pull up a few shoots and look closely where the leaf blade meets the stem. Here is what to check on colonial bentgrass:

• Vernation: Rolled in the bud.
• Ligule: Short and thin (membranous).
• Auricles: None.
• Leaf blade: Very fine and light green.
• Growth habit: Dense, upright and bunch-like with very high shoot density. Short rhizomes may give rise to short stolons (UC IPM, Michigan State).

Where colonial bentgrass is grown in the US

Colonial bentgrass is a lawn grass in northern Europe and New Zealand, and Michigan State says it is used as turf in some northeastern and northwestern US states. On golf courses it is better suited to fairways and tees than greens.

It does best in cool, humid weather. UC IPM lists it for general lawn areas in the coastal regions of northern California. It does poorly in heat, drought, salt and traffic.

Penn State, writing about bentgrasses in Pennsylvania, says they are not suitable as lawn grasses under normal care and are not compatible in mixes with other cool-season grasses.

Colonial bentgrass pros and cons

Pros

• Very fine, soft, dense turf
• Some shade tolerance
• Better dollar spot resistance than creeping bentgrass (Michigan State)
• Takes low mowing

Cons

• Moderate to high maintenance
• Low heat, drought, salt and traffic tolerance
• Slow to recover from wear
• Very susceptible to brown patch (Michigan State)
• Heavy thatch
• Needs frequent, close mowing
• UC IPM says it is susceptible to most turfgrass diseases

Grasses that look like colonial bentgrass

How and when to plant colonial bentgrass

Ways to plant: Seed (UC IPM).

Seeding rate: 0.5 to 1 lb per 1,000 sq ft (UC IPM).

Seeding dates change from state to state. See when to plant grass seed by state, or our Pennsylvania grass seed guide if you are in PA.

How to care for colonial bentgrass

Mowing: Mow closely at 0.5 to 1 in. and often, to avoid scalping (UC IPM). If left unmowed it forms a mat that can hold soil in place.

Watering: Water often to keep its shallow roots alive (UC IPM).

Fertilizing: Apply 3 to 5 lb of nitrogen per 1,000 sq ft per year during active growth (UC IPM).

Nitrogen per year: 3 to 5 lb N per 1,000 sq ft per year, applied during active growth from March through June and September through November in California (UC IPM).

Overseeding: UC IPM seeds it at 0.5 to 1 lb per 1,000 sq ft. Penn State does not suggest bentgrasses for regular lawns.

Thatch: Heavy; needs regular dethatching and aeration (UC IPM).

Common colonial bentgrass problems

If a pesticide is needed, use only products labeled for that use; the label is the law. If you hire someone to treat a lawn, make sure they hold your state’s pesticide applicator license; see our pesticide applicator license guide. To put a name to a lawn weed, use our weed identification guide.

Questions we get about colonial bentgrass

Similar lawn grasses

Annual ryegrassLolium multiflorumChewings fescueFestuca rubra subsp. commutataCreeping bentgrassAgrostis stolonifera