Turfgrass Management Terms Q - R

Raceme - an inflorescence in which the spikelets are pedicelled on a rachis

Radicle - first baby root that emerges from a seed and becomes the plant’s primary root. When reseeding lawns, you want good contact between the seed and the soil. Otherwise, the radicle will die out before taking root

Rebuilding - term that refers to practices involving complete changes in the total turf area, i.e., reconstruction of a green, tee, fairway, rough or any other area of the golf course

Red thread - common summer lawn fungus disease. More cosmetic than deadly, it gives a lawn a ragged look through the reddish blades that give it its name. Red thread is commonly caused by improper watering and fertilization practices. Compacted soil and excess thatch are also to blame

Reel mower (cylinder mower) - contain a rotating cylinder comprised of several blades that chop the grass with a scissor-like cut. The first mower, invented in 1831, was a reel mower

Renovation - turf improvement involving replanting into existing live and/or dead vegetation

Resiliency - capability of the turf to spring back when balls, shoes, or other objects strike the surface, thus providing a cushioning effect

Retrorse - directed back or downward

Rhizomatous - having rhizomes

Rhizome - are horizontal, underground root-like stem by which some types of grasses spread to develop new roots and shoots. Because the spreading stems are protected underground, rhizomatous grasses hold up very well to heavy foot traffic and recuperate quickly from injuries 

Rings - describes areas of diseased turf surrounded by healthy turf to the inside and outside of the affected area

Root vegetables – edible plants grown primarily for their enlarged roots. These include vegetables such as carrots, beets and parsnips

Root zone – layer of soil in which the roots of the grass plants are found. Also a growing medium

Rust - disease caused by a fungus that results in a layer of reddish-orange material forming on the leaf or stem surface. The rust material will come off the plant readily when rubbed

Ryegrass - genus of cool-season grasses unrelated to cereal rye used in breads and flours. Known for fast germination, ryegrasses are often used in seed mixes for quick establishment, early color and erosion control. Annual ryegrass naturally dies after one season, regardless of climate. Perennial ryegrass comes back year after year when grown in the appropriate zone. Southern lawn owners often overseed their soon-to-be-dormant, warm-season lawns with ryegrass in fall for temporary winter color 


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