Washington prairies, including the Reserve, were full of useful plants. Native people cultivated and harvested about two-thirds of these plants for food, medicine, or other purposes. Women harvested and dried meadow grasses, especially bear grass, to combine and contrast with wetland plants in basket-making. Women also harvested edible camas bulbs in large enough quantities to trade. Some Native people today are introducing children to harvesting and cooking camas bulbs, to hand on this traditional food source.

A technique of regular controlled burning was used to sustain the prairie ecosystem. Bear grass, for example, depends on regular burning for strong growth, and is known as the first plant to reappear after a fire. Burning the prairies increased plant diversity, maintained open areas for harvesting, and kept visibility for hunting. Otherwise, prairies would get swallowed up by Douglas firs. The practice was ended as settlers turned prairies into farms.

A few researchers have found that native plants get a head-start over exotic species in recovering from fire.