Wildflowers decorate the park every spring and summer. The most spectacular blooms come from the huge patches of bluebells in the bottomland adjacent to the river.
Native plants and animals have lost large amounts of habitat because of the encroachment of exotic species within the park and the entire St. Louis metropolitan area. The principal offenders are the bush honeysuckle (lonicera maackii) and Japanese honeysuckle (lonicera japonica). These plants have no natural enemies and grow so densely that they smother any growth of native vegetation.