Identifying problems such as pests, diseases and weeds is a crucial element of daily golf course maintenance. Let's focus on a few of the major warm season weeds today. Yes, we have them. Personally, these imperfections are sometimes all I can see while driving the course. A weed is defined as a plant that is not valued where it is growing and is usually of vigorous growth.
Yellow nutsedge resembles a grass plant but is technically in the sedge family. It can be identified by its yellowish green color and triangular shaped stem. It is a very aggressive grower. That plant that is twice as tall as your turf and already needs trimmed again just a couple days after mowing, that's probably nutsedge. It will grow just about anywhere but thrives in excessive moisture. Nutsedge is a perennial that spreads by underground rhizomes and nutlets. Hand pulling this weed is usually not productive as more plants will form out of these nutlets in the ground. A very selective herbicide that targets sedges is the best plan of attack to control these little monsters.
Crabgrass and goosegrass are somewhat similar plants that can be easily confused with one another. Both are grassy annual warm season weeds. Both tend to grow in less than ideal often compacted soils and areas void of healthy turf. Crabgrass normally shows up earlier in the season when soil temperatures reach 55-60 degrees. Soil temps need to reach 60-65 degrees for goosegrass seeds to germinate. The easiest way to distinguish the two is by looking strait down at the center of the plant. Goosegrass has a circular white center with the stems resembling the spokes of a wheel. Goosegrass also has a darker green and thinner grass blade and tends to grow more horizontally. Conversely, the grass blades of crabgrass are wider that tends to grow taller. A thick and healthy stand of grass is the best defense against any weed, but a well timed pre-emergent herbicide can help prevent crab and goosegrass populations. Effective post emergent selective herbicides are available for crabgrass but there are not many options for goosegrass.