MINNESOTA WEEDS, SERIES III g 



Eradication. — Stray plants of nodding wild rye may be pulled and 

 destroyed before seeds set. If a field is badly infested, which is not 

 often, the plants should be cut for hay when first headed out and the 

 land plowed and cropped for a year or two. 



Hemp (Cannabis sativa L.) 



Other common names. — Carl hemp, fimble, callow-grass. 



Description. — Hemp is a weed in barnyards, waste places, along 

 roads and river banks, and also in cultivated fields. It is an annual 

 plant from three to ten feet high and is very rough and hairy and 

 strongly scented. The stout upright stem has a tough inner bark con- 

 taining strong fibers for which the plant is often cultivated. It blos- 

 soms from July to September, the seeds ripening from August to 

 November. It is propagated only by seed. The grayish oval seed 

 are fed to caged birds. Hemp seeds are seldom found in commercial 

 seed except oats and then only when the oats are from a hemp-growing 

 district. 



Eradication. — Wild hemp is not difficult to eradicate if the plants 

 are prevented from seeding. Cutting the crop often enough to stop 

 the formation of seed is the first step. Plowing waste places and 

 seeding to more desirable crops, thus occupying the land, is the second 

 step. Plowing land that has grown wild hemp and planting a culti- 

 vated crop, hoeing where necessary to remove stray plants, is usually 

 most effective. 



Common Smartweed (Polygonum hydro piper L.) 



Other common names. — Water pepper, biting knotweed. 



Description. — Smartweed is an annual plant growing in moist or 

 wet locations and is commonly found in barnyards, gardens, and 

 waste places. It flowers from June to September and its time of seed- 

 ing is from July to November. The leaves are quite narrow and arc 

 very acrid and peppery. It grows from ten inches to two feet tall 

 and is light green to reddish in color. This plant spreads only by seeds 

 and is not considered a bad weed pest in this state. The seeds of the 

 common smartweed are dull brownish black in color, more or less 

 three-sided and quite pointed at the apex, and are often found in com- 

 mercial seed of red clover, alfalfa, millet, timothv, and flax. 



