Though some gardeners describe cannas as garish, others see these colorful, easy to grow plants as indispensable in the landscape.  Cannas tolerate a tremendous range of growing conditions, from dry, sunny beds to shaded aquatic gardens.  Rhizomes should be planted anytime from April to August.  They will grow just about anywhere, but flowering is best in full sun to part sun.  They will bloom, however, will as little as 3 hours of direct sun.  Growth is fastest in moist, fertile soil, but these plants are not picky.  Plant rhizomes just below the soil surface in average garden soil.  Each canna shoot produces only one bloom spike, and when the flowers have faded, you can trim off the spent spike, or cut the entire shoot down to the ground.  Cannas are really bothered by the canna leaf-roller.  This caterpillar can cause terrible damage by chewing holes in the leaves, turning the leaves brown, and binding the leaves and flower buds together with silk.  The best solution is applications of acephate, Sevin, or B.t. on a regular basis.