Spiderwort. There are many varieties of Spiderwort available to gardeners, all of them presenting a long display of triangular flowers over a clump of grassy leaves. Plants should be trimmed back hard after the first flush of flowers is over, to rejuvenate the foliage and encourage repeat bloom in late summer. Happiest in a sunny, moist site. Divide clumps every 2 to 3 years in spring.