Common Name: montbretia
Type: Herbaceous perennial
Family: Iridaceae
Zone: 6 to 10
Height: 2.00 to 2.50 feet
Spread: 1.50 to 3.00 feet
Bloom Time: July to September
Bloom Description: Yellow
Sun: Full sun to part shade
Water: Medium
Maintenance: Medium
Flower: Showy, Good Cut
Attracts: Hummingbirds, Butterflies
Tolerate: Rabbit, Deer, Drought
Culture
Grow in medium moisture, moderately fertile, well-drained soil in full sun to part shade. Prefers full sun in cool summer climates, but appreciates some part afternoon shade in hot summer climates such as the St. Louis area. Tolerant of some drought once established. Plant corms in spring after last frost date approximately 3-4” deep and 6” apart. These plants may not be reliably winter hardy throughout USDA Zone 5 where they will benefit from being sited in protected locations (e.g., near the south side of a house) and mulched in winter. Corms may be lifted in fall, dried and stored for winter in a dry medium in a cool but frost-free location.
Noteworthy Characteristics
Crocosmia is a genus of about 7 species of cormous plants from grasslands in South Africa. Montbretias are good fresh cut flowers that are frequently used in commercial flower arrangements.
Crocosmia × crocosmiiflora is an interspecific hybrid resulting from a cross between C. aurea and C. pottsii.
Genus name comes from the Greek words krokos meaning saffron and osme meaning a smell for the smell of dried flowers steeped in warm water.
Specific epithet means Crocosmia-flowered.
'Buttercup' is a compact, clump-forming cultivar that can reach up to 2.5' tall and spread to fill a 3' area. Can reach larger spreads in ideal growing conditions. The luminous, buttercup-yellow, tubular flowers (up to 1.5" in diameter) are held on unbranched flowering stalks above the upright, sword-like foliage. Blooms from mid-summer into fall. Very attractive to hummingbirds, butterflies, and other pollinators. This selection also makes an excellent cut flower with a long vase life.
Problems
Spider mites can cause significant damage to the foliage, and, if left unchecked, can impair normal flowering. Winter hardiness is a concern in the St. Louis area. Deer and rabbits tend to avoid this plant.
Uses
Perennial borders in groupings or masses. Also effective in containers where lifting corms for winter is rather simple.