Native Plants for Iowa

Iowa is the most thoroughly converted state in the country by land area, and the statistic that matters to a gardener is that its original prairie survives on a fraction of one percent of the ground. But the parts that resisted conversion are remarkable, and they define what grows well here.

Along the Missouri River in western Iowa, the Loess Hills rise in steep ridges of wind-deposited silt piled deep enough to stand in bluffs. Formations of that depth are rare worldwide. The soil drains sharply, the west-facing slopes bake, and the plants there are dry-prairie specialists: little bluestem, sideoats grama, leadplant, and prairie coneflower on ground that behaves more like western Nebraska than like central Iowa.

The northeast corner is the Driftless Area, which the last glaciers missed entirely. It is hilly, cut by cold spring-fed streams, and holds relict populations from the ice age on north-facing slopes where cold air drains out of fractured rock all summer.

The middle of the state, and its water

Between those two edges lies the Des Moines Lobe, the youngest glacial surface in Iowa, and the prairie pothole country. That ground is flat, exceptionally fertile, and naturally wet. Nearly all of it has been drained by tile, but yards still reveal the original pattern: a low corner that stays saturated through April is a pothole in miniature.

Plant it accordingly. Wet-prairie and sedge-meadow species belong in those spots and establish without any soil work at all, while a dry-prairie species set into the same place will rot at the crown in its first spring.

Establishing prairie in deep soil

Iowa's soil is deep enough that prairie plants can root as far down as they were built to, which is why an established prairie planting here is close to close to self-sufficient once it takes. Getting to established is the work: prairie species put nearly everything into roots for the first two seasons and can look disappointing above ground while doing it.

Sow or plant in fall so seed gets the cold, damp stratification most prairie species require, keep the site weeded through the first two summers, and judge the planting in year three rather than year one.

Confirming what is native to your county

The Iowa Prairie Network and the state's county conservation boards, an unusually strong county-level system here, both maintain remnant sites open to visitors. Iowa State University Extension publishes regional native plant guidance, and a visit to a nearby remnant during the growing season is the fastest education available.

Sources: Iowa Department of Natural Resources (landform regions and prairie remnants); Iowa State University Extension and Outreach (native plant guidance); USDA PLANTS Database (native status by state).