Laserfiche WebLink
Leafy Spurge <br />vegetative growth stage. <br />Page 2 of 4 <br />Leafy spurge has an extensive root system that is abundant in the top foot of soil, and it <br />may grow 15 feet deep or more. Roots contain substantial nutrient reserves that allow <br />the weed to recover from stress, including control efforts. Many vegetative buds along <br />roots grow into new shoots. This contributes to its persistence and spread. <br />Phenology <br />Leafy spurge shoots originate in early spring from crown tissue just below the soil <br />surface and from sporadic buds along the root system. Leafy spurge is very competitive, <br />one of the first plants to emerge each spring, and uses moisture and nutrients that <br />otherw(se would be available for more desirable vegetation. <br />Flowering occurs primarily in April and May but may occur through fail. Bracts emerge <br />about two weeks before flowers and give leafy spurge the appearance of flowering. For <br />optimum herbicide application timing, it is important to recognize true flower emergence. <br />Each flowering shoot produces an average of 140 seeds. Seeds are expelled up to 15 feet <br />when capsules dry. They are viable up to eight years in soil. Water, birds, animals and <br />people aid seed dispersal. Seeds readily Float and waterways are good sources for new <br />infestations. <br />Peak seed germination generally occurs in May. Seedlings quickly acquire the ability to <br />reproduce vegetatively by developing buds on roots within 10 to 12 days after <br />emergence. Perennial leafy spurge is more difficult to control than seedlings. <br />Management <br />Leafy spurge is difficult to manage <br />and can recover from almost any <br />control effort. Therefore, a <br />management scheme that combines <br />control methods over four to five <br />years is recommended. Even after <br />that time, monitor infestations for <br />recurrence and adopt a maintenance <br />program. <br />Cultural control. Vigorous grass <br />growth is an important aspect of leafy <br />spurge control. Over-grazing stresses <br />grasses and makes them much less <br />competitive with weeds, leafy spurge <br />in particular. Irrigation, where - , ;~ <br />applicable, may favor grass growth <br />and make it more competitive with ~~~ddd <br />leafy spurge. <br />Chemical control. For optimum leafy <br />spurge control, proper timing of <br />herbicide application is imperative. <br />Research from North Dakota State <br />University indicates that Tordon 22K <br />(picloram) 2,4-D, <br />Banvel/Vanquish/Clarity (dicamba) <br />are most effective when applied in <br />spring when true flowers emerge (not Flgure 2: Leafy spurge (Euphorbia esula L.) <br />just bracts). Fall application to leafy <br />spurge regrowth also is good timing for these herbicides. <br />Roundup (glyphosate) is most effective when applied sequentially (1.0 quart per acre (A) <br />http:/Jwww. ext.colostate.edu/pubs/natres/03107.htm1 <br />6/20/2005 <br />