When choosing an herbicide, make sure that it will control the weed and that it is recommended for your turf. Before using, read the entire label and follow it precisely for rate and timing. The following tips will help you achieve optimum control.
Grassy vs. Broadleaf: Grassy weeds are true grasses which emerge from seed as a single leaf. The leaf blades are longer than they are wide and have parallel veins. An example is crabgrass.
Proper management practices include mowing, watering, fertilizing, and liming. These are mentioned briefly here but are covered in detail in corresponding HGIC fact sheets. See HGIC 1205, Mowing Lawns, HGIC 1207, Watering Lawns, and HGIC 1201, Fertilizing Lawns.
Guidelines for Using Postemergence Herbicides
The main reason homeowners want to rid their lawn of weeds is that they are aesthetically disruptive. In other words, weeds are ugly and interrupt an otherwise uniform appearing lawn. Weeds are also fierce competitors and will rob the turf of sunlight, nutrients and moisture. Lastly, weeds have a tendency to spread rapidly. A few left uncontrolled can quickly become a serious problem.
Tall fescue should be mowed at heights between 2½ and 3½ inches, and mowed frequently enough so that no more than ⅓ of the blade is removed. For turfgrass in partial shade, the mowing heights may be raised slightly. Proper mowing heights will encourage a dense, healthy stand.
Annual vs. Perennial: Annuals germinate, grow, and die within a twelve month period. Summer annuals, such as goosegrass, germinate in the spring, grow through the summer, set seed, and die at the onset of cold weather. Winter annuals, such as chickweed, germinate in the fall, grow through the winter, set seed, and die as temperatures rise in early summer.
Table 1. Preemergence Granular Herbicides for Lawns.
Experts recommend planting a blend of two or three cultivars rather than seeding just a single cultivar. This broadens the genetic base and gives the turf a better chance of withstanding a variety of challenges. Use a seeding rate of 6 pounds per 1,000 square feet (sq ft). Do not assume more seed is better. Higher seeding rates can result in weak, thin stands that are more susceptible to disease and high temperature stress.
Kentucky bluegrass produces a high-quality, medium- to fine-textured turf when grown in the right climate (Figure 9–3). In North Carolina, it is well suited for the mountains and can be grown in combination with tall fescue in the piedmont. It is not suitable for use in the coastal plain. Kentucky bluegrass prefers fertile, limed, well-drained soils in sun or light shade. Excellent sod results from rhizomes (underground stems) that spread, with most cultivars recuperating from and tolerating pest control measures and moderate levels of traffic. Many new cultivars with improved color, texture, and pest resistance are now commercially available.
III. What to Plant
Even though Kentucky bluegrass may turn brown during a two- to four-week summer drought, it is not necessary to irrigate. Letting the grass go dormant prevents it from becoming stressed by drought conditions. Kentucky bluegrass recovers well from most droughts, and watering often increases disease problems.
Perennial ryegrass is similar in appearance to Kentucky bluegrass but is only adapted to the mountains (Figure 9–5). In North Carolina it is never seeded alone but always mixed with Kentucky bluegrass. These grasses complement each other because perennial ryegrass establishes faster than Kentucky bluegrass, and Kentucky bluegrass has the ability to spread and fill in damaged areas.