Compact-America Kentucky Bluegrass

What Makes It Different

This group does two useful things at once, and they turn out to be connected. It is the shade group and it is one of the two water-thrifty groups.

The shade part is mostly a disease story. Powdery mildew is the shade disease of Kentucky bluegrass: shade does not only starve the plant of light, it keeps the canopy still and damp, and mildew takes hold there. Compact-America cultivars resist powdery mildew, and they resist summer patch and leaf spot as well. So in the same light where a Midnight-type lawn goes white, dusty and thin, this group holds its density. Extension sources rate its shade tolerance moderate to good — the best in a species whose baseline is poor.

The water part is separate and independently documented. In the Kansas State deficit-irrigation trial, Compact-America and Mid-Atlantic were the two groups that went longest between waterings before wilting. Pair that with a fine leaf and high shoot density and you get a lawn that stays presentable on a schedule that would make a Midnight-type lawn look tired.

Everything else follows the species. Cold hardiness is identical across all five bluegrass groups; winter dormancy here is moderate rather than long, and summer recovery is moderate rather than fast.

Who It’s For

The strip on the north side of the house. A back lawn with two or three mature maples where you get morning sun and afternoon shade. A Front Range or plains yard under alternate-day watering rules. Any lawn where you have been told bluegrass will not work because of shade, but the shade is dappled rather than total.

It is not the answer for deep shade under a closed canopy, and it is not a low-input grass in absolute terms — it still wants 2 to 4 lb of nitrogen a year and it still goes dormant in a long drought. It is thrifty relative to its siblings, not relative to fine fescue.

The Cultivars

What Changes In Care

Feed less, mow higher, and water on a longer interval — the mowing and feeding changes come from the shade, not from the cultivar type.

• Halve the nitrogen in shade. A shaded lawn needs about half what a sunny one does. This group sits at 2 to 4 lb per 1,000 sq ft a year in full sun, so a shaded lawn may want 1 to 2.
• Mow at 3 to 3.5 inches in shade so a thin canopy has more leaf area to catch what light it gets. In full sun, treat it like any other improved bluegrass.
• Stretch the interval, not the depth. The thrift shows up as more days between waterings, not as less water per watering. Still soak 4 to 6 inches down each time.
• Morning sun still matters. Mildew resistance is not immunity, and this group is no less exposed to brown patch and dollar spot on leaves that stay wet all morning. If you can only clear one side of the canopy, clear the east side.

Before You Buy

The biggest mistake on this page is buying it for the wrong degree of shade. A lawn under a closed tree canopy needs 50 to 90% fine fescue, not shade-tolerant bluegrass — no bluegrass carries deep shade on its own. Use this group for partial shade and mix it with fine fescue as the shade deepens: roughly 30 to 50% shade-type bluegrass to 50 to 70% fine fescue, seeded at 3 to 4 lb per 1,000 sq ft.

• The type name is never on the bag. No law requires it, so you identify this group by reading the variety names on the analysis label against the list above.
• Use the A-LIST and TWCA tags as a shortcut for the water claim. Both are independent programs that test under reduced inputs at university sites, so an approved variety is a checkable claim rather than a marketing line.
• Buy certified, blue-tag seed and check the test date. Repackaged 1, 5 and 25 lb lots from specialist suppliers usually carry a certified-seed guarantee and a printed analysis; big-box bags generally show neither.
• Never plant a single cultivar — three to five unrelated ones, since bluegrass is clonal and a monoculture has nothing to fall back on.
• Keep perennial ryegrass under 10% by weight, and in a wet maritime climate such as western Washington cap total bluegrass at 30% of the mix and lead with fine fescue and ryegrass instead.