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• BACKGROUND <br />Leafy spurge (Euphorbia esula) is adeep-rooted, long-lived perennial weed that is native to Eurasia and is <br />extremely difficult to control. In North America, leafy spurge is very competitive and can cause the <br />displacement of native vegetation. Large areas of pure stands result in reductions in plant diversity, loss <br />of wildlHe habttat, and reduction in land values. Livestock carrying capadty of infested land is very low <br />because forage production is reduced and because cattle and some wildlife will not graze in infested <br />areas. The following information in this section is summarized from Lajeunesse et al (1995). <br />Leafy spurge begins growing in early spring from buds on the crown (the junction between root and stem) <br />and mots, as well as from seed. Some seed germination can oowr any time adequate moisture is <br />available. Flowering begins in late spring and is usually completed by mid-summer. Seeds develop for 20 <br />to 30 days after flowering. Calendar dates vary wtth climate and geographic location, and flowering and <br />seed production can occur throughout the summerrf soil moisture is available. <br />Each flower produces a lobed capsule containing three seeds. When the stem matures, the capsules <br />explode, projecting seeds up to 15 feet. Part of each crop of leafy spurge seeds can remain dormant and <br />viable for as long as 8 years. Dormancy can last even longer 'rf seeds are deeply buried. <br />• Leafy spurge seeds are dispersed several ways. The seeds float on water, often resulting in new <br />infestations along ditches, rivers, and in areas that are periodically flooded. Seeds can be spread by <br />animals in the mud on their feet or are eaten by sheep, goats, rodents or birds and then deposited in <br />dung. Seeds and sometimes root pieces can also be widely spread as contaminants in crop seed, feed <br />grain, or hay and on vehicles and equipment. <br />Shoots develop from leafy spurge's numerous stem and root buds as well as from seeds. Stem buds <br />cause branching of stems, while new shoots develop from root buds when older shoots are removed or <br />the crown is damaged. <br />The root system is comprised of both vertical and horizontal roots. Main vertical roots can grow to depths <br />of 26 feet. Horizontal roots, which grow near the soil surface, can extend 15 feet per year from the parent <br />plant. Each root bud is capable of producing a new, independent plant. Root buds have been found at <br />depths of 10 feet or more. The depth, extent, and thick corky bark of the roots enable leafy spurge to <br />survive during periods of drought, grazing, or herbicide applications. In addition, the roots contain a large <br />food reserve that can sustain the plant for years and can provide the energy needed for new shoots to <br />emerge from buds after chemical or mechanical treatments. The deep and extensive root system makes <br />• leafy spurge especially difficult to control. <br />1 <br />