Dietes bicolor
yellow fortnight lily
Overview
Dietes bicolor is an evergreen, clump-forming perennial reaching 24-36 inches (60-90 cm) tall and wide, growing from rhizomes. The narrow, sword-shaped leaves are 24-36 inches (60-90 cm) long and arise in flat fans from the base. Branched flower stems carry flat, iris-like flowers 2-3 inches (5-8 cm) across, pale to bright yellow with three dark maroon-brown blotches near the center, each ringed with a thin orange margin. Individual flowers last about one day, but the plant produces flushes of bloom at roughly two-week intervals through spring and summer, the source of the name fortnight lily. Round seed capsules follow, and stems may bend to the ground under their weight, rooting where they touch. Foliage stays green year-round in mild climates. The plant is hardy only in frost-free to light-frost areas and is damaged below about 25 F (-4 C).
Native Range
Native to the Eastern Cape of South Africa, where it grows on stream banks and damp, grassy slopes. Widely planted as a landscape perennial in Mediterranean and subtropical climates.Suggested Uses
Planted in borders, mass plantings, and along driveways and paths at 18-24 inch (45-60 cm) spacing, and used for erosion control on banks. Tolerant of heat, wind, and coastal conditions, it suits low-water landscapes in mild climates. Grows in containers of at least 3 gallons (11 L).How to Identify
Appearance
Size & Dimensions
Height2' - 3'
Width/Spread2' - 3'
Bloom Information
Flowers in flushes from spring through summer, roughly September through autumn in the southern hemisphere and late spring through summer in the northern. Each flower lasts about one day, with a fresh flush opening about every two weeks. Warmth and adequate moisture sustain repeated flushes; bloom slows in cool weather and drought.
Detailed Descriptions
Flower Description
pale yellow with maroon blotchesFoliage Description
greenGrowing Conditions
Sun Requirements
Requires 4-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Grows in full sun to part shade in most well-drained soils, tolerating both moist ground and periods of drought once established. Water regularly for steady flowering, though established clumps survive on rainfall alone in mild climates. The plant needs little feeding and spreads slowly into larger clumps over several years. It is hardy only to about 25 F (-4 C) and is grown as a container or greenhouse plant in regions where winters are colder. Few pests or diseases affect it. Old clumps can be lifted and divided in spring.Pruning
Remove spent flower stems at the base after flushes finish, since stems can produce more buds if left in place. Cut away damaged or browned leaves at ground level to keep the fans tidy. Removing developing seed capsules reduces self-seeding.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
summerfall
Container Growing
✓ Suitable for container growing
Minimum container size: 3 gallons