What are upright grasses and bent grasses?

Q: What is the difference between “upright grass” and “bent grass” and how do I know which one I have?

A.: Turf grasses are divided into two main types: upright and bent.  Upright grasses include fescue, bluegrass, annual rye grass and perennial rye grass. These grasses have blades that come straight up out of the soil. Upright grasses thrive in more humid regions with moderate temperatures and are often called “cool season” grasses. They are prevalent in Northern lawns but can be found in Southern United States too, especially in irrigated lawns.

The bent grasses include Bermuda, zoysia, centipede, seashore paspalum and St. Augustine. These grasses spread by rhizomes and stolons which creep along the ground. Rhizomes are roots that usually grow just beneath the surface while stolons are stems, which usually sprawl at or just below the surface.  Fine blades grow upward from the stolons, or stems, which are sometimes called “runners”, thus the name “bent grass”. The bent grasses tolerate higher temperatures and drought conditions better than the upright grasses and so are common on the Southern United States and other warmer regions throughout the world.

Mowing height recommendations for all turf grasses vary from one region to another, but generally the upright grasses are cut higher than the bent grasses. One exception is St. Augustine. Although it is a bent grass common in the southern states, universities throughout the south recommend cutting it to heights similar to those of the upright grasses.

If you are unsure which grass type you have, or if you have a mixture of upright and bent  grasses in your lawn, then the best approach for you is choosing a mower with a mowing height range that works well in your lawn. You can also find out what kind of grass you have by contacting your local Master Gardener program.

Do you have an unusual situation in your lawn that makes choosing a mower particularly challenging?