Turf weeds are divided into five classes for determining
the appropriate method of control: (1) annual grasses,
(2) annual broadleaf weeds, (3) perennial grasses, (4) perennial
broadleaf weeds and (5) miscellaneous weeds. Annual
weeds are further classified as summer or winter annuals.
Summer annuals germinate in spring and die in fall, while
winter annuals germinate in fall and die in late spring.
Perennial weeds are further classified as warm-season or
cool-season to identify when they are prevalent and determine
when they should be controlled.
Annual grasses germinate, grow, and produce seeds each
year. They resemble desirable turfgrasses in their growth
habits, but differ in texture and color. Crabgrass and foxtail
are examples of annual grasses.
Annual broadleaf weeds also complete their life cycle
from seed within one year but generally require different
control measures from grass weeds. They contrast more
sharply from turfgrasses in form and texture. The leaf width
is often much broader than that of turfgrass. Examples of
annual broadleaf weeds include chickweed, henbit and
Perennial grasses persist for more than one growing
season because of their perennial root system, even though
the topgrowth may die each winter. Most perennial grasses
cannot be selectively controlled in turfgrass. Some perennial
grasses such as Bermudagrass and tall fescue are weeds in
bluegrass lawns, for example, but by themselves can make a
desirable turf. Other perennial grass weeds are nimblewill
Perennial broadleaf weeds persist from year to year, but
can be selectively controlled in turfgrass. If perennial weeds
are to be chemically controlled, they must be actively
growing. Dandelions and bindweed are examples of
perennial broadleaf weeds.
Biennial weeds are treated as perennials for control
purposes. Biennials grow vegetatively for one year and
flower and seed in the second year. Examples include wild
carrot, mullein, and some thistles. Some weeds such as black
medic may fit more than one class.
Miscellaneous weeds include those that are neither true
grasses nor broadleaf weeds. Nutsedge, wild garlic, algae
and moss fall into this category. These sometimes require
special control methods.