Question: Do you have any suggestions for tall and narrow perennials? My garden is tight on space.
Answer: Yes. Tucson-based garden designer Scott Calhoun offers these suggestions. All are at least twice as tall as they are wide. None require staking or pruning to maintain their shape.
Unless otherwise noted, all require full sun.
SHOWN: Palmer's penstemon (Penstemon palmeri)
4 to 5 feet tall and 2 feet wide. A fragrant, heat-tolerant plant with light pink early summer flowers. A Southwest native that needs dry conditions. Zones 4–9.
'Autumn Minaret' daylily (Hemerocallis 'Autumn Minaret')
2 to 3 feet wide, with flower stalks rising to 5 or 6 feet in mid- to late summer. Gold- and rust-colored flowers. Zones 3–9.
Ava's hummingbird mint (Agastache x'Ava')
2 to 5 feet tall and half as wide. Rosy pink flowers from early summer to autumn. Zones 5–9.
'Herbstonne' coneflower (Rubeckia 'Herbstonne')
6 to 8 feet tall and 4 feet wide. A yellow coneflower that can take some shade but may require staking there. Blooms all summer. Also known as 'Autumn Sun'. Zones 5–9.
Joe-pye weed (Eupatorium fistulosum)
4 to 7 feet tall and 2 to 4 feet wide. Large heads of tiny pink flowers appear in mid- to late summer. Zones 3–8.
Maximilian's sunflower (Helianthus maximiliani)
3 to 10 feet tall and 2 to 4 feet wide. 3-inch sunflowers appear in late summer. Zones 4–9.
Prairie dock (Silphium terebinthinaceum)
3 to 10 feet tall and 1 to 3 feet wide. Bears yellow daisylike flowers on branched stems in late summer and autumn. Zones 4–8.
West Texas grass sage (Salvia reptans)
A fine-textured grassy sage to 4 feet tall and half as wide, with deep blue autumn flowers. Zones 5–9.
This list first ran in the September 2007 issue of Horticulture.
Image by Stan Shebs. Source and licensing