How to Grow Flax Lily (Dianella): Planting, Care and Varieties

Flax lily (Dianella) is one of the easiest strappy-leaved perennials for warm US gardens. It grows in clumps of sword-shaped leaves 18 to 36 inches tall, tolerates drought once established, handles sun or part shade, and rarely needs more than one cleanup a year. Most gardeners grow the variegated form, Dianella tasmanica ‘Variegata’, for its cream-and-green striped foliage, which brightens borders, foundation beds and containers all year in zones 8 to 11. Plant it in well-drained soil, water it regularly for the first season, and it will fill out into a tidy, evergreen clump.

In this guide

1. What Is Flax Lily?
2. Popular Flax Lily Varieties
3. Where Flax Lily Grows: Zones and Climate
4. Choosing a Planting Site
5. How to Plant Flax Lily
6. Watering and Feeding
7. Growing Flax Lily in Containers
8. Pruning, Dividing and Maintenance
9. Pests, Diseases and Problems
10. Design Ideas for Flax Lily
11. Flax Lily Care Calendar (Zones 8–11)
12. Frequently Asked Questions

What Is Flax Lily?

Dianella is a genus of clumping, evergreen perennials native to Australia, Asia and the Pacific. It is not related to true flax (Linum) or to lilies; the common name comes from its flax-like leaves. In the US it is widely planted in Florida, the Gulf Coast, Southern California and Arizona as a lower-maintenance alternative to liriope and daylilies, with a cleaner, more upright look.

The plant spreads slowly by short rhizomes, forming clumps that widen a few inches each year. In late spring and summer it sends up wiry, branched stalks of small, nodding blue to violet flowers with yellow stamens, followed by bright purple-blue berries that can persist for weeks. The berries are ornamental but should be treated as inedible and kept away from small children and pets.

Popular Flax Lily Varieties

Variety	Foliage	Size	Best use
Dianella tasmanica ‘Variegata’	Green with cream-white stripes	2–3 ft tall and wide	Borders, shade brightener, containers
Compact variegated selections	Bold white margins	18–24 in	Edging, small beds
Dianella revoluta selections (e.g. ‘Little Rev’)	Blue-gray, upright	18–24 in	Full sun, dry beds, modern designs
Dianella caerulea selections	Green to blue-green	1.5–2.5 ft	Mass plantings, coastal gardens
Dianella ensifolia	Green, sometimes striped	2–4 ft	Tropical-style borders

Availability varies by region. Garden centers in Florida and the Gulf states mostly stock the variegated tasmanica type, while West Coast nurseries carry more blue-gray revoluta and caerulea selections. Check the label for mature size; compact cultivars are better for edging walkways and patios.

Where Flax Lily Grows: Zones and Climate

Flax lily is reliably evergreen in zones 9 to 11 and generally hardy in zone 8, where foliage may be damaged when temperatures drop into the low 20s°F. Leaves often recover in spring if the crown survives. Mulching 2 to 3 inches deep over the root zone in late fall improves survival in zone 8. In zone 7 and colder, treat flax lily as a container plant that comes indoors or into a bright garage when nights fall below about 30°F.

It handles heat and humidity well, which is why it is so common in Florida landscapes. It also tolerates salt spray better than many perennials, making it useful in coastal gardens a short distance back from the beach.

Choosing a Planting Site

Light

Flax lily grows in anything from full sun to fairly deep shade, but the best site depends on the type:

• Variegated forms: morning sun and afternoon shade, or bright filtered light under high tree canopy. In full afternoon sun in hot climates, the cream stripes can scorch and brown.
• Blue-gray and solid green forms: full sun to part shade. They hold color well in hot, sunny beds.
• Deep shade: plants survive but grow looser and flower less.

Soil

The one condition flax lily will not tolerate is waterlogged soil. Sandy soils, loams and amended clays all work if water drains within a few hours after rain. In heavy clay, raise the bed 6 to 8 inches or mix in compost and fine pine bark across the whole bed, not just the planting hole. A soil pH between about 5.5 and 7.5 is fine.

How to Plant Flax Lily

Plant in spring or fall in zones 8 and 9, and almost any time except the hottest weeks of summer in zones 10 and 11. Fall planting in warm climates lets roots establish during cooler weather.

1. Space the plants. Set 1-gallon plants 18 to 24 inches apart on center for a border, or 12 to 18 inches for a solid mass. Larger 3-gallon plants can go 24 to 30 inches apart.
2. Dig the hole. Make it twice as wide as the root ball and the same depth.
3. Loosen the roots. Tease apart circling roots on pot-bound plants.
4. Set the crown at grade. The top of the root ball should be level with the surrounding soil. Planting too deep invites crown rot.
5. Backfill and water. Firm the soil gently and soak the area thoroughly.
6. Mulch. Spread 2 inches of pine straw or shredded bark, keeping it an inch or two away from the base of the leaves.

Watering and Feeding

For the first 8 to 12 weeks, water two or three times a week in warm weather, keeping the root zone moist but not soggy. After the first season, flax lily is drought tolerant in most of its range and usually needs water only during extended dry spells, about once a week in summer heat in places like Phoenix or inland Southern California. In Florida, normal rainfall is often enough once plants are established.

Flax lily is a light feeder. Apply a slow-release, balanced fertilizer once in spring at the label rate, or top-dress with an inch of compost. Too much nitrogen produces floppy growth and can reduce variegation contrast. If leaves look pale yellow across the whole plant in alkaline soil, a micronutrient fertilizer containing iron and manganese usually corrects it.

Growing Flax Lily in Containers

Flax lily makes an excellent container plant, especially the variegated type, which acts as a “spiller-and-thriller” in one. It is also the only practical way to grow it in zone 7 and colder.

• Pot size: start a 1-gallon plant in a 12 to 14 inch pot. Mature clumps fill a 16 to 20 inch container.
• Mix: a quality potting mix with about 20 percent added pine bark fines or perlite for drainage. Do not use garden soil.
• Watering: water when the top 1 to 2 inches are dry. In summer that may be every two to three days; in winter indoors, every one to two weeks.
• Feeding: a slow-release fertilizer in spring, or a liquid feed at half strength monthly from April through September.
• Overwintering: bring the pot into a bright, cool room or sunny garage before frost. Keep it on the dry side until spring.

Pair it with plants that share the same light needs. In part shade, flax lily works well with ferns, coleus and caladiums. In sun, combine the blue-gray types with lantana, ornamental grasses and succulents. For more on combining strappy plants with grasses, see our fountain grass growing guide.

Pruning, Dividing and Maintenance

Annual cleanup

Flax lily does not need shearing. Once a year, in late winter or early spring, pull or cut out brown, damaged and dead leaves at the base and remove spent flower stalks. If cold damage was severe, you can cut the whole clump back to about 4 inches; healthy crowns resprout quickly once warm weather returns. Avoid shearing the clump into a flat-topped mound, which leaves blunt brown leaf tips for months.

Dividing

Divide every 3 to 5 years when clumps become crowded or bare in the center, or any time you want more plants. Dig the clump in spring or fall, cut it into sections with a sharp spade or knife so each piece has several fans of leaves and a good root mass, and replant at the same depth. Water well for the next few weeks. Division is the most reliable way to propagate named varieties, since seedlings may not match the parent plant.

Reverted green leaves

Variegated plants sometimes produce solid green fans. These grow more vigorously and can take over the clump. Cut reverted fans out at the base as soon as you see them.

Pests, Diseases and Problems

Flax lily has few serious problems, and it is generally less attractive to deer than many perennials, although no plant is fully deer proof.

• Root and crown rot: the most common cause of death. Signs include yellowing, collapsing fans and a mushy base. Improve drainage and cut back on irrigation.
• Leaf scorch: brown, crispy stripes on variegated types in hot afternoon sun. Move the plant or add shade.
• Leaf spot: brown spots in prolonged wet, humid weather. Remove affected leaves and water at the base early in the day.
• Scale and mealybugs: occasional, mostly on stressed or container plants. Wipe off small infestations and use horticultural oil or insecticidal soap for larger ones.
• Brown tips: usually from drought stress, salt buildup in containers or fertilizer burn. Flush containers with plain water and trim tips at an angle to keep a natural look.

Design Ideas for Flax Lily

Flax lily’s tidy, upright habit makes it a strong structural plant. Some of the best uses:

• Edging: a row along a walkway or driveway gives a clean, consistent line that does not flop over pavers.
• Foundation beds: mass it in front of shrubs to hide bare lower stems.
• Under trees: variegated flax lily lights up dappled shade under oaks and palms, where turf struggles.
• Ground cover alternative: planted 12 to 18 inches apart, it knits into a weed-suppressing mass. See our ground cover plants guide for low-growing companions.
• Water-wise beds: blue-gray types blend with agaves, muhly grass and other drought-tolerant plants.

For more perennials that look good with minimal care, visit our flowers and perennials hub.

Flax Lily Care Calendar (Zones 8–11)

• February–March: remove dead and damaged leaves; cut back cold-damaged clumps; fertilize as growth starts.
• April–May: plant and divide; refresh mulch; watch for flower stalks.
• June–August: water established plants during dry spells; shade variegated types if scorch appears.
• September–October: second planting window; divide crowded clumps.
• November–January: mulch crowns in zone 8; move containers indoors in colder zones before frost.