What are tall fescue clumps in a lawn?

Seeing tall fescue clumps in a lawn is common in Pennsylvania, and it confuses a lot of homeowners because tall fescue is also sold as a lawn grass. The problem is mixing. Older, coarse, pasture-type tall fescue grows in thick bunches, and when it pops up in a fine-textured Kentucky bluegrass or ryegrass lawn, it stands out like a cowlick.

Tall fescue is a cool-season perennial grass from Europe, widely planted for pastures, hay and roadsides. It usually arrives in lawns through cheap seed mixes, contaminated topsoil or a lawn built on old farm ground.

Modern turf-type tall fescues are finer and look great as a whole lawn. It’s the coarse bunches mixed in with other grasses that cause trouble.

How to identify tall fescue clumps

• Texture: blades are noticeably wider and coarser than bluegrass or ryegrass, often a quarter inch or more across.
• Veins: run a finger across the top of the blade and you’ll feel raised, parallel ridges. The underside is smooth and glossy.
• Edges: slightly rough to the touch when you slide your finger down from the tip.
• Collar: a short membrane ligule and small, blunt auricles with a fringe of tiny hairs.
• Growth habit: tight, round clumps that get wider each year. They grow fast in spring and look shaggy soon after mowing.
• Season: green all year. In winter, the clumps often stay darker green than the lawn around them.
• Seedhead: a loose, open, branched panicle in late spring if left unmowed.

Where it grows in Pennsylvania

Tall fescue is everywhere in rural Pennsylvania: pastures, hay fields, road banks and reclaimed land. It’s tough, deep-rooted and drought-tolerant, which is why it was planted so widely.

In home lawns, clumps often show up on lots built on old farm fields, along areas repaired with off-site topsoil, and in lawns seeded with bargain mixes that list “tall fescue” or “Kentucky 31” on the label. Once it’s there, it doesn’t leave on its own.

Its deep roots are a big reason it survives where other grasses thin out. Fescue clumps often stay green through a dry August while bluegrass goes dormant, which makes them stand out even more in late summer. The same toughness is why mowing, raking or ordinary lawn care won’t make them fade away.

Tall fescue look-alikes

Tall fescue often gets mistaken for crabgrass. Crabgrass is light green, hairy, lies flat and dies at the first frost. Fescue clumps are dark green, upright and stay green into winter. That difference matters, because crabgrass products won’t touch fescue.

Quackgrass also has coarse blades, but its long auricles clasp the stem and it spreads in lines by rhizomes. Orchardgrass is another clumping pasture grass with folded blades and a tall, papery ligule.

How to get rid of tall fescue clumps

Here’s the honest part: there’s no easy selective spray for homeowners that removes tall fescue from a bluegrass lawn. Lawn weed killers target broadleaf weeds, and crabgrass products don’t affect established fescue.

• Dig them out: for a handful of clumps, cut around each one with a sharp spade, lift out the crown and roots, fill with topsoil and seed or patch with sod.
• Spot-treat and reseed: glyphosate applied carefully to just the clumps kills them, roots and all. It also kills any grass it touches, so use a shield or a wiper. Reseed the dead spots after the label’s waiting period.
• Timing: late summer is ideal. Treat or dig in August, then reseed from late August through September, when cool-season grass establishes best in central PA.
• Professional-only options: a few products can suppress tall fescue in Kentucky bluegrass, but they’re costly, take repeat applications and generally aren’t sold to homeowners.
• Or blend it in: if clumps are everywhere, consider overseeding the whole lawn with a modern turf-type tall fescue, so the texture evens out instead of fighting it.

Always read and follow the herbicide label (the label is the law) and confirm it’s labeled for your site. In Pennsylvania, applying herbicide for hire requires a PA Department of Agriculture pesticide applicator certification, so a full-lawn renovation should go to a licensed lawn-care company.

Keeping it from coming back

Read the seed label before you buy. Avoid bargain mixes containing pasture-type tall fescue if you want a fine bluegrass lawn, and buy certified seed with low weed and other-crop content.

Be careful with fill and topsoil from farm fields, which often carry fescue seed. Mowing regularly at a consistent height helps clumps blend in, and catching new clumps while they’re small makes digging them out a five-minute job.

If you renovate, finish with a seed mix that matches the rest of your lawn so new patches blend in.

Questions we get about tall fescue (clumps in lawns)

Similar weeds

QuackgrassElymus repensLarge CrabgrassDigitaria sanguinalisCreeping BentgrassAgrostis stolonifera