Huge, eye-popping flowers, with silky petals in shades of yellow to red, are a great reason to grow these unusual poppy relatives. The cup-shaped blossoms are supported by short stems rising from a basal clump of silver-green leaves about a foot wide and high. (Some species branch more than others.) Seed pods sport spiny “horns,” giving the plant its common name. Native to the eastern Mediterranean, Horned Poppies are listed as noxious weeds in some states (happily, not Colorado). Interestingly, the plants contain the chemical glaucine, which is used medically (and rarely as a recreational hallucinogenic drug—not recommended).
Horned poppies are grown from seeds or started seedlings. While the seedlings will overwinter in mild areas (to USDA zone 6), here it’s best to start them in early spring. Choose a spot in full sun. Soil must be well-drained for these xeric plants. Lightly cover the seeds, which can take a while to germinate. Once plants reach blooming size, they will continue to flower until seeds are formed or until frost. Removing spent blooms prolongs flowering, but if you want more plants next year, be sure to let some seed pods ripen. Pick them and scatter the seeds where you want plants to grow next season. A pea gravel mulch will keep weeds in check, mitigate soil temperatures and moisture levels, and encourage self-seeding.
Low-growing Horned Poppies belong up front where they can be seen, combined with other drought-tolerant plants. Complement the big, bold flowers with blooms of contrasting colors, shapes and sizes. Red-orange Glaucium grandiflorum looks striking next to purple catmint (Nepeta). Try pairing G. flavum with smaller-flowered rockroses (Helianthemum) or hardy ice plant (Delosperma). Pineleaf penstemon (Penstemon pinnifolius) has spikes of tiny flowers that harmonize with both poppies in the same yellow-to-red hues.
Article and photos by Leslie Holzmann, Certified Colorado Gardener