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The seeds may be planted in well-spaced basins or in rows 2-4 feet (1.2 m) apart, just as you would plant cucumbers or squash. You should plant the seeds in late spring when the soil is warm and there is no danger of frost. Soaking the seeds of Proboscidea parviflora ssp. parviflora in warm tap water appears to stimulate germination and increase the percentage of young seedlings. Seeds should be covered with a half inch (1.3 cm) of soil (preferably with a top layer of planter mix/mulch) and kept moist until germination. Annual devil's claw plants grow in a variety of soils, but thrive in rich loam soil with regular weekly soaking. They are very heat tolerant and their blossoms and foliage make an attractive mid-summer flower garden. Proboscidea louisianica ssp. louisianica readily reseeds itself and becomes naturalized, but poses no serious threat to your garden unless you step on one of the hooked claws barefooted.
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http://waynesword.palomar.edu/ww0801.htm
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