Soapweed yucca is a Great Plains species native to Wyoming. The lance-like leaves are stiff, coarse, and sharp but worth the blood-letting for the tall spikes of whitish pendulant flowers. Yuccas don’t bloom every year, but some years are phenomenal. Because of the shape of the flower, pollination can be accomplished by only a single species of insect, the yucca moth. Female yucca moths lay eggs in the ovary and then deliberately pack pollen on the stigma. The growing moth larvae eat the developing seeds but usually not all of them. Before the fruits open to disperse seeds, the caterpillar chews its way out and drops to the ground, where it buries itself, spins a cocoon, and waits out the winter. In the spring, the moths emerge just as the yucca blooms and wait at the flowers to find a mate. In our area, the Yucca tend to bloom about every 3 years. It is a spectacular site. (information from University of Wyoming Extension)