MISSOURI BOTANICAL GARDEN BULLETIN 125 
plant that is useless or troublesome and which persists upon 
places where it is not wanted. Some plants, however, which 
are called weeds, may be ornamental and useful in suitable 
situations; and perhaps the best definition of a weed is a 
“plant out of place.” 
The beauty of a lawn is due chiefly to its smoothness and 
the uniformity of color and texture of the grass. Therefore, 
_ any plant which tends to detract from this appearance must 
be eradicated. The farmer is able to get rid of the noxious 
weeds by means of thorough cultivation and crop rotation, 
but of course such a treatment is not feasible upon a lawn 
and other means must be sought. However, the weed prob- 
lem loses some of its importance if the lawn is well made 
and, above all, well kept and fertilized. Fertilization helps 
by keeping up a constant and vigorous growth of the lawn 
- grass, thus preventing weeds from getting a foothold. An- 
other factor which may keep weeds in check is heavy seed- 
ing with Kentucky bluegrass two or three times during the 
season. The seed form a fine mat over the entire area, pre- 
venting bare spots wherein weed seed may lodge and germ- 
inate. The young weed seedlings cannot withstand a dense 
— of young grass and are killed out even should they 
nd a favorable spot for germination. eee 
The most common weeds that infest lawns are crab grass 
Digitaria hwmifusa), quack grass (Agropyrum repens), 
andelion (Taraxacum officinale), plantain (Plantago 
Rugelii), chickweed (Stellaria media), moneywort (Lysi- 
machia Nummularia), shepherd’s purse (Capsella Bursa- 
pastoris), and pigweed (Amaranthus retroflexus). 
The crab grass and quack are very difficult to eradi- 
cate once they become established. The former is an annual 
and may be gotten rid of by raking off the — early 
in the spring, seeding down with good grass seed, and by 
constant mowing, especially in the fall, in order to prevent 
the maturing of the seed. In this way after several years the 
lawn may be freed of the pest. The only treatment avail- 
able for the quack grass is radical in its nature and con- 
sists of plowing up the lawn, growing a cultivated crop a 
_ the land for one year, and then reseeding. Of the other 
weeds mentioned, dandelion and plantain may be eradicated, 
if not too abundant, by cutting the tops with a knife. If 
all the leaves are kept cut so that there will be no food stored 
a the roots, these will eventually starve and the plant will 
One of the most efficient methods of weed eradication 1s 
by means of a chemical spray which kills the weeds with- — 
