Wildflowers & perennials

What this group is

Herbaceous perennials: plants with no woody stem that die back to the ground each winter and return from the root. It is the largest group on this site and the one most people mean by native plants.

A few here are technically something else. Virginia bluebells is a spring ephemeral, completing its whole above-ground year in about ten weeks before going dormant. California poppy and desert marigold behave as perennials in mild climates and as reseeding annuals elsewhere. Autumn sage and Turk's cap are subshrubs, woody at the base and herbaceous above.

Buy for succession, not for the display bench

Nurseries sell what is in flower, so a garden assembled over three or four spring visits is a garden that flowers in spring.

The stretches that matter most to insects are the ones nobody buys for. Late March and April, when bumblebee queens are founding colonies alone with no stores. Late July and August, when the early perennials are done and the fall species have not started. And September into November, when new queens are feeding before winter and monarchs are moving south.

Pick something for each of six windows across the season rather than a dozen things that all peak in June. Pasque flower and golden alexanders open the year; foxglove beardtongue and lanceleaf coreopsis bridge to summer; blanketflower, mountain mint, and chocolate flower carry the heat; the asters and goldenrods close it.

The two habits that decide where a plant goes

Perennials divide into clumpers and spreaders, and the distinction predicts more about your future workload than anything on the label.

Clumpers stay where they are put. Purple coneflower, prairie dropseed, rattlesnake master, butterfly weed, and Culver's root will occupy the same footprint for many years. Several of them build a deep taproot, which makes them effectively permanent and also impossible to move later, so site them once.

Spreaders travel, by rhizome or by seed. Common milkweed, obedient plant, mountain mint, and Maximilian sunflower all will. That vigor is exactly what makes them useful on a bank or in a meadow, and exactly what makes them a chore next to something slow.

Neither habit is a fault. Putting one where the other belongs is.

Two rules that cover most failures

Do not improve the soil. Most of these species evolved in lean unamended ground, and compost and fertilizer produce soft tall growth that falls over and rots in winter. Flopping is nearly always a fertility or light problem rather than a staking problem.

Cut back in spring, not fall. Stem-nesting bees overwinter inside hollow stems and many insects overwinter in the litter, so a bed cleaned out in October throws away the season's work. The seed heads feed birds in the meantime.

Sources: Lady Bird Johnson Wildflower Center, University of Texas at Austin (species profiles and growth habits); Xerces Society (bloom succession, overwintering habitat, and spring and fall forage gaps); Mt. Cuba Center (native perennial trials on longevity, habit, and garden performance).