80 WEED FLORA OF IOWA 



Sheep Sorrel (Bumex acetosella L.). 



Description. — A low smooth annual or perennial, usually the lat- 

 ter, growing from 6-12 in. high, producing an erect stem, with hori- 

 zontal, creeping, woody root-stocks or rhizome; petioled, narrowly- 

 hastate, narrow, lanceolate leaves, the upper linear; flowers on 

 jointed pedicels, dioecious, small, in a terminal naked panicle ; small 

 green calyx ; exserted stamens ; the valves not enlarging in fruit. 



Distribution. — Sheep sorrel has long been known as a troublesome 

 weed in Europe, and in the northern states ; perhaps indigenous to 

 the United States ; at least now common across the continent in the 

 north. It is common everywhere in Iowa, more particularly in sandy 

 or gravelly soils. 



Extermination. — The plant succumbs quite readily to cultivation, 

 and where the iields are thoroughly cultivated with hoed crops, it 

 is seldom troublesome more than one season. In fact the vast ma- 

 jority of plants may be killed by cultivating the soil once or twice. 

 The roots though produced abundantly seem to be unable to stand 

 drying. The soil on which it occurs should receive a heavy coat of 

 manure. This seems to be approved by Dr. Halsted who says: 

 ' ' This pest can be subdued by keeping the infested land under the 

 plow for a short time. ' ' - 



Clark and Fletcher say in regard to this weed: "Sheep sorrel 

 is said to be an index of soil characters. It seems to thrive best on 

 sandy or gravelly soils deficient of lime. An application of lime to 

 slightly acid soils produces a more vigorous growth of cultivated 

 crops and curtails the opportunities of the sorrel to grow and spread. 

 Old meadows and pastures that are overrun with it and that can- 

 not well be brought under cultivation may be pastured with sheep 

 for two or three years to prevent it from seeding freely. 



A three-year rotation of crops with good cultivation, including 

 shallow plowing directly after hay crop and frequent cultivation 

 until autumn to prepare for hoed crops, will keep sheep sorrel well 

 under control even on lands that seem to be specially suited to its 

 growth. ' ' 



Wallace 's Farmer suggests the following : "To control this weed 

 in the meadows we would suggest applying manure and thickening 

 up the grass stand. Putting the land into a cultivated crop destroy! 

 this weed. ' ' 



