Blue-eyed grass

Sun

Full sun to light partial shade; flowering is best in sun.

Water

Moderate; prefers evenly moist soil but tolerates brief dry spells once established.

Soil

Average to humus-rich, well-drained soil that retains some moisture; avoid persistently waterlogged ground.

Height

1-2 ft (0.3-0.6 m)

Spread

0.5-1 ft (0.15-0.3 m)

Flowers

Late spring to early summer; small blue to violet-blue flowers with yellow centres, opening mainly in sunshine.

Foliage

Narrow, upright, green, grass-like leaves in small tufts; usually dies back in cold winters but may remain partly green in mild climates.

Growth

Moderate

Care needed

Low

• Pollinators
• Deer resistant
• Cold hardy
• Low allergen

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Fairly tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   1 ft (0.3 m)

2. After 1 year

   1.1 ft (0.35 m)

3. After 2 years

   1.3 ft (0.4 m)

4. After 3 years

   1.5 ft (0.45 m)

   full size

About 3 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Native to

the US and Canada

Growth rate

Moderate

• Water during establishment and prolonged dry weather; do not leave the roots standing in water.
• Apply a thin layer of compost in spring on poor soil; avoid heavy feeding.
• Keep mulch away from the crown to reduce the risk of rot.
• Divide crowded clumps every two or three years to maintain vigour.
• Remove seed capsules before they ripen if you want to limit self-seeding.

Pruning. Remove spent flower stems after flowering unless you want seed. In late winter or early spring, trim away dead leaves without cutting into fresh green growth.

Early spring

Remove dead foliage and check that neighbouring plants have not crowded the clumps.

Spring

Plant or divide established clumps, then water them thoroughly.

Late spring

Keep the soil lightly moist while flowers and new growth develop.

Early summer

Cut off finished flower stems to prevent unwanted seedlings, or leave a few capsules for seed.

Summer

Water during extended dry spells rather than giving frequent light sprinklings.

Autumn

Remove heavy fallen leaves from the crowns and check drainage before winter.

• Repeat small groups along a sunny path or border edge for a low, informal rhythm.
• Mix with low-growing meadow flowers and sedges in a small native planting within its North American range.
• Place among stones in a moisture-retentive rock garden, rather than a very dry scree bed.
• Use at the front of a mixed border where its fine leaves contrast with broader foliage.

Garden styles it suits: Cottage garden, Native meadow, Wildlife garden, Pollinator garden, New perennial (prairie) and Small-space.

Plant it with: Prairie smoke, Wild columbine, Lanceleaf coreopsis, Prairie dropseed, Foxglove beardtongue and Butterfly weed.

Wildlife: The flowers provide pollen for small native bees and other pollen-collecting insects. Its value is greatest when planted with other locally appropriate flowering species that extend the season.

• Crown or root rot in waterlogged soil: improve drainage or move the plant to a slightly raised position.
• Poor flowering in shade: move to a sunnier position and avoid nitrogen-rich fertiliser.
• Thin or declining clumps: divide healthy outer sections in spring and replant in fresh soil.
• Unwanted seedlings: remove seed capsules before they dry and pull surplus seedlings while small.

Toxicity to cats, dogs, horses and people is not well documented for this species, and no plant part should be assumed edible. Species-specific safety information is limited; discourage children and pets from eating it and do not use it as livestock forage.

• Yellow-eyed grass (Sisyrinchium californicum)

  Has similar narrow leaves and small iris-like flowers, but the flowers are yellow rather than blue-violet.

• Pale yellow-eyed grass (Sisyrinchium striatum)

  Forms a much larger clump with broader, grey-green leaves and tall stems carrying tiers of pale cream-yellow flowers.

The common name describes its grass-like leaves and blue flowers, while angustifolium means narrow-leaved.

Propagation. Divide clumps in spring, keeping roots and several healthy shoots on each division. Alternatively, sow fresh seed outdoors in autumn; winter chilling can help germination, which may be uneven.

Accepted botanical name

Sisyrinchium angustifolium

In the US and Canada

Native in Canada and the lower 48 states.

Native range

Alabama, Arkansas, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Illinois, Indiana, Iowa and Kansas.

Measured

Soil pH 5 to 7.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.