Gardening 101: Flax Lily

Flax Lily, Dianella tasmanica

When your sister politely asks you what to plant in front of her partly shaded fence where deer mingle too frequently in an area where cars drive too close–and she says she needs a plant that looks good all year with no maintenance because she’s a working mom and can’t bother with one more thing—please suggest Dianella. She will love you (even more) for it.

A sturdy flowering perennial that grows in low clumps and hails from Australia, Dianella can play a similar role to ornamental grasses in a landscape.

Please keep reading to learn if Dianella, commonly known as flax lily, is your sister-saving (or garden-saving) plant.

Dianella is a clumping, strap-leafed perennial rising to 30 inches tall, with sturdy bladed foliage that fans out from a central clump. A tropical plant that can survive a frost, flax lily is recommended for USDA growing zones 7 to 11 (a range which varies by cultivar).

Star-shaped flowers with prominent golden anthers (typically blue or white, depending on the cultivar) arrive in the spring and are followed in mid-summer by oblong rich metallic-blue berries.

In 1837, the first specimen of Dianella tasmanica was collected by South African botanist Ronald Campbell Gunn off the coast of Australia, in Tasmania. This perennial also is native to moist, shaded forests in Victoria and along the east coast of New South Wales. Hardy to about 20 degrees Fahrenheit, this grass look-a-like plant is a member of the lily family and grows energetically and spreads by rhizomes in coastal full sun (where it will proliferate with regular irrigation), but is more reserved and controllable in part-sun locations with minimal irrigation.

There are many Dianella cultivars to know about and each has its own unique coloring. Some are banded with yellow, others with pure white, and one has a red-tinged base. These varieties really stand out in the garden from a long distance and provide superior foliage interest in container combinations and as accents in shaded spots.

Some favorites: Dianella tasmanica ‘Variegata’  and Dianella tasmanica ‘Silver Streak’ both have white striped blades, and Dianella tasmanica “Yellow Stripe” has lemon yellow, lime, and dark green bands.

Cheat Sheet

• Dianella attracts native birds and insects.
• Flax lily is extremely successful in dry shade, where it imparts a tropical vibe.
• Dianella is a superb choice for mass planting under large trees.
• The foliage, flowers, and berries of flax lily are attractive additions to flower arrangements.
• Happily, flax lily is not bothered by hungry deer.

Keep It Alive

• Flax lily does best in partial shade to heavy shade.
• Dianella tasmanica tolerates clay, sand and some water-logging but prefers well-drained soils.
• Prevent rapidly colonization of Dianella by watering infrequently.
• Once established, flax lily can be drought tolerant.
• To keep flax lily looking tidy, remove expired or tattered leaves throughout the growing season. Use sharp clippers and cut the leaf far back into the plan. Also remove any spent flowers and their stems.

See more growing tips in Flax Lily: A Field Guide to Planting, Care & Design in our curated guides to Perennials 101. See more grassy options in Grasses 101. For more inspiring landscapes, read: