Ask Mr. Smarty Plants

You have a wide choice of native plants suitable for a rain garden.  Which ones to choose depends mainly on whether the wet part of your garden remains wet all the time or whether, as in most rain gardens, it dries up part of the time.  A good place to select species based on their need for water is a website sponsored by the city of Austin. Listed there are species that require constant water and those that can thrive in dry or wet conditions.  Another criterion is plant size.  Assuming that you have a relatively small rain garden and need small plants, I suggest a few possibilities that do well in dry or wet soil, beginning with the smallest ones.  Hydrocotyle bonariensis (Largeleaf pennywort), Phyla nodiflora (Texas frogfruit), Teucrium canadense (Canada germander), Conoclinium coelestinum (Blue mistflower), Aquilegia canadensis (Eastern red columbine), Physostegia intermedia (Intermediate false dragonhead)Justicia americana (American water-willow), Lobelia cardinalis (Cardinal flower) and Helenium autumnale (Common sneezeweed).  Grasses are very important in absorbing water.  Consider Muhlenbergia reverchonii (Seep muhly), Andropogon glomeratus (Bushy bluestem), Muhlenbergia capillaris (Gulf muhly), Tripsacum dactyloides (Eastern gamagrass), Panicum virgatum (Switchgrass) and Muhlenbergia lindheimeri (Lindheimer's muhly).  For the wetter spots, you could plant sedges, such as Rhynchospora latifolia (Sand-swamp whitetop sedge) and Carex cherokeensis (Cherokee sedge).

Check out your local plant nurseries for the species you decide on.  Seeds of some of the plants are also available from Native American Seed.  Your best chances for success are to get the plants or seeds in the ground before hot weather arrives.  Thank you for your efforts to conserve water.