perennial

Fortnight Lily

Dietes grandiflora

$19.99

The Story

Plant Bio

Dietes grandiflora, the fortnight lily, is an evergreen rhizomatous perennial forming dense, upright clumps of rigid, sword-shaped leaves. Erect, slender stems bear large white flowers with yellow nectar guides and pale violet style arms in repeating flushes throughout the warm months.

This species is distinguished by its fan-like foliage arrangement and its perennial flowering stalks, which produce successive blooms over multiple years. Individual flowers last only a few days, but new buds open continuously to maintain the display.

Uses & Benefits:

Provides structured, architectural evergreen foliage and reliable, repeating flushes of white and violet flowers throughout summer.

Highly drought-tolerant once established and tolerates coastal salt spray, making it ideal for low-maintenance landscapes.

Attracts native bees, butterflies, and other generalist insect pollinators to the garden.

Essentials

At a Glance

Plant Type

Perennial

Height

48"

Width

36"

Light

Full Sun, Partial Sun

Zones

8, 9, 10

Water

Low to Moderate

Humidity

High

Lifespan

Perennial

Native To

South Africa

Toxicity

Mildly toxic to pets and humans

Bloom period

Summer

In flower about 3 months of the year

Marketplace

Where to Buy

Plants By Mail

1+ Gal Pot

In Stock$19.99

Shipping costs Year-round shipping Free shipping

Planting

How to Grow

Select a planting site in full sun to partial shade with well-drained soil.
Dig a hole twice the width of the root ball and set the rhizome clump level with the surrounding soil.
Water thoroughly after planting to settle the soil, then establish a moderate watering schedule.
Apply a balanced slow-release fertilizer in early spring to support the summer flowering flushes.

Pro Tip

Never cut back or shear the tall flowering stems after blooming; these stalks are perennial and will produce new flowers season after season.

Keep It Thriving

Care Guide

Do

Cut back dead or yellowed leaves at the base of the plant to maintain a clean appearance.
Ensure positive drainage to prevent root rot in heavy clay soils.
Clip off spent seed pods if you wish to prevent self-seeding in the garden.

Don't

Do not shear or cut down the rigid flowering stems, as they bloom repeatedly over multiple years.
Do not overwater, especially in heavy shade, which leads to weak, floppy growth and root rot.
Do not plant in low-lying, waterlogged areas where water pools.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Divide
Fertilize
Pest Check
Spring Cleanup

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Mass PlantingBorder EdgingCoastal GardensMediterranean GardensFoundation Planting

Companion Plants

Salvia leucantha Agapanthus praecox Rosmarinus officinalis

Multiply

Propagation Methods

Good to Know

Common Questions

Fortnight Lily questions

What zones can Fortnight Lily grow in?

Fortnight Lily is hardy in USDA Zones 8–10. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is Fortnight Lily deer resistant?

Yes — Fortnight Lily is rated deer-resistant. Deer typically pass it over, though extreme hunger can override any plant's defenses.

When does Fortnight Lily bloom?

Fortnight Lily typically blooms in summer through summer. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does Fortnight Lily need full sun?

Fortnight Lily does best in full sun to part shade. In hot climates, afternoon shade keeps blooms fresher longer.

Is Fortnight Lily drought tolerant?

Yes — once established (usually after the first full season), Fortnight Lily handles dry spells with minimal watering. Water deeply its first year to build the root system that makes that possible.