Actual size and flowering may vary slightly based on season.
Fortnight Lily
Fortnight Lily, also called African iris, forms an upright fan of long, stiff, strap-like leaves about 2 to 4 feet tall. In spring and early summer it sends up stalks of white, iris-like flowers about 3 inches across, marked with yellow and violet. Each flower is short lived, but the same stalks keep opening new ones through the season. It adds a clean, grassy texture to a border, a bed near a water feature or a planting under open trees.
Best for: grassy texture in perennial borders, beds near fountains and water features, plantings under open trees, and spring white flowers.
Its long, stiff leaves grow in an upright fan about 2 to 4 feet tall and wide. Plant it 2 to 3 feet apart along a border to add a grassy line behind lower flowers.
It suits beds near water features and greener oasis plantings that get regular water. The white flowers stand out against the leaves in spring and early summer.
It grows in full sun to part shade, and in the low desert some shade from the west sun in summer is best. A spot under tall, open trees gives it that light shade.
Full western sun in summer stresses it, so keep it out of hot, exposed corners. Soil that stays wet can turn the leaves yellow and burn the tips.
- Border or mass planting2 ft apart
- Single clumps with room3 ft apart
Water a new plant every 2 to 4 days for the first few weeks, then water less often. Once rooted, keep up regular water in summer and let the soil drain between soakings.
Plant it in full sun to part shade. In summer, protect it from the hot west sun to avoid heat stress.
Cut off spent flower stalks and seed pods. It needs no other pruning.
Drainage test first. Dig the hole and fill it with water. If water is still sitting in the hole a day later, you likely hit caliche, clay or hard soil, so fix the drainage before planting. If it drains very fast, the soil is sandy. Standing water around roots is a common reason new plants fail.
Weed cloth. Cut it away from the planting hole and where the roots will spread. Remove any plastic sheeting completely, since it keeps water and air out of the soil.
Rock or decomposed granite with no soil underneath. Bring in soil close in texture to your native soil, mix it with the soil below, and build up enough depth for roots before planting.
If you can break through. Use a breaker bar, pick, or jackhammer. Dig through the caliche and break out the solid chunks. Backfill with the soil you dug out, with no compost or manure in the hole. Confirm drainage before planting.
If you cannot break through. Dig narrow holes through the hard layer beside the root ball, not under it, and refill them with the same soil, not gravel. If it still will not drain, plant on a low mound of the same soil.
Root ball. Check the outside edges for any roots circling around. Loosen or cut those so they grow outward. Do not break up the center of the root ball.
Depth. The top of the root ball should sit at or just slightly above the surrounding soil level. Planting too deep can lead to rot and kill the plant.
Drip emitters. At planting, put the emitters on the root ball, on different sides of the plant. After about 2 months, move them to the outer edge of the root ball. Over the first year, add emitters farther out toward the edge of the branches as roots grow. Once a plant is rooted, never water only at the trunk.
How big does fortnight lily get?
It grows about 2 to 4 feet tall and about as wide, as an upright fan of stiff, strap-like leaves. Give it that room when you plant.
When does fortnight lily bloom?
It blooms in spring into early summer. The white flowers, about 3 inches across, have yellow and violet markings.
Why do the flowers last such a short time?
Each flower is short lived and often lasts just a day. The same stalk keeps opening new flowers one after another, so the plant keeps flowering from spring into early summer.
Does fortnight lily need sun or shade in Phoenix?
It grows in full sun to part shade. In the low desert, give it protection from the hot west sun in summer, such as light shade under open trees.
How often should I water fortnight lily?
It handles some dry spells, but in Phoenix it looks best with regular water. Let the soil drain between waterings so it never stays soggy.
How cold hardy is fortnight lily?
It is rated hardy to about 15°F. It is an evergreen plant, so it keeps its leaves through the winter.
How far apart should I plant it?
Plant about 2 to 3 feet apart, center to center. Use 2 feet for a border or mass planting, and the Spacing tab counts plants for you.
Should I cut off the old flower stalks?
Yes, remove spent flower stalks and seed pods to keep it tidy. Left alone, the heavy seed pods bend the stalks to the ground, where they can start new plants.
Why are the leaves turning yellow?
Soil that stays wet, especially alkaline soil, can turn the leaves yellow and burn the tips. Water less often and make sure the bed drains.
What is the difference between fortnight lily and bicolor iris?
They are close relatives, and both are sometimes sold as fortnight lily. This one has white flowers with yellow and violet marks, while bicolor iris has pale yellow flowers with dark spots.
Is it the same as Moraea?
Yes. It used to be sold as Moraea, and the name Dietes vegeta is often used for it too. Today it is listed as Dietes iridioides.
Fortnight Lily for sale in Arizona, delivered to you
Fortnight Lily is Dietes iridioides, an African iris with stiff strap leaves and white flowers marked with yellow and violet. It blooms in spring and early summer and suits borders and garden beds with regular water. Below is what to expect in a Valley yard: size, spacing, sun, water and how it differs from bicolor iris.
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Fortnight lily in Phoenix gardens
Fortnight lily is an African iris with stiff, strap-like leaves and white flowers marked with yellow and violet. It blooms in spring and early summer and grows 2 to 4 feet tall.
Does fortnight lily need shade in Phoenix?
It grows in full sun to part shade. In the low desert it does best with protection from the west sun in summer.
How often do you water fortnight lily in Arizona?
In Phoenix it looks best with regular water through the summer. Use soil that drains so the roots never stay soggy.
How far apart do you plant fortnight lily?
Plant about 2 to 3 feet apart, center to center. The Spacing tab counts plants for a border or bed.
Fortnight lily vs bicolor iris
Both are Dietes and both can be sold as fortnight lily. Dietes iridioides has white flowers, while Dietes bicolor has pale yellow flowers with dark spots.
Do you cut back fortnight lily?
It needs no regular pruning. Remove spent flower stalks and seed pods to keep it neat.
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