What hardiness zones is Stipa gigantea suitable for?

Stipa gigantea (syn. Celtica gigantea) is giant feather grass (golden oats), a cool-season evergreen ornamental grass. The basal foliage clump grows 18-24 inches (45-60 cm) tall and 36-48 inches (90-120 cm) wide of narrow rolled dark green to gray-green arching leaves. Towering flower culms rise to 60-96 inches (150-240 cm / 5-8 feet) with enormous open airy golden panicles 12-18 inches (30-45 cm) of pendant oat-like florets bearing long twisted glistening awns in summer (June-July). The panicles glow gold and amber when backlit by low-angle sun. The dried panicles persist for 6-8 months through fall and winter. In the grass family (Poaceae). A 'see-through' plant: the tall airy flower stems are transparent enough to allow views through to plants behind. RHS Award of Garden Merit. Cool-season grass. Native to the Iberian Peninsula (Spain and Portugal), growing on dry rocky hillsides, scrub, and open pine woodland. Sharp drainage — intolerant of wet winter soil. Do not cut the evergreen foliage clump — only remove old flower culms. Non-toxic. Deer-resistant. Drought-tolerant. Full sun. Zones 6-9. Growth rate is slow to moderate.

Native Range

Native to the Iberian Peninsula (Spain and Portugal), growing on dry rocky hillsides, scrub, and open pine woodland.

Suggested Uses

Planted as a specimen and in borders in zones 6-9. The 'see-through' airy panicles allow views through to plants behind. Position where the panicles catch low-angle sun. Sharp drainage. 6-8 months of panicle display. Non-toxic. Deer-resistant.

How to Identify

Identified by towering flower culms 5-8 feet (150-240 cm) with enormous open airy golden panicles of pendant oat-like florets bearing twisted awns, rising from a compact evergreen foliage clump. The 'see-through' airy panicles and the glistening awns are diagnostic. Synonym Celtica gigantea. In Poaceae.

Appearance

Size & Dimensions

Height2' - 8'

Width/Spread3' - 4'

Reaches mature size in approximately 3 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~8 weeks

Summer

Summer (June-July), lasting 6-8 weeks of active flowering. The dried golden panicles persist 6-8 months through winter. The panicles glow in backlit low-angle light.

Detailed Descriptions

Flower Description

Silver-gold; enormous open airy panicles 12-18 inches (30-45 cm) with pendant oat-like florets bearing long twisted glistening awns; the panicles glow gold and amber when backlit

Foliage Description

Narrow, rolled, dark green to gray-green, arching; the foliage clump is 18-24 inches (45-60 cm) tall

Growing Conditions

Sun Requirements

Full Sun

Requires 6-10 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 8.0(Neutral)

357912

Soil Types

sand chalk rocky loam

Drainagewell drained

Water & Climate

Water Needs

Very Low

Frost Tolerance

hardy

Time to Maturity

2-3 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Full sun. Sharp drainage — intolerant of wet winter soil. Tolerates alkaline and chalky soil (pH to 8.0). Do not cut the evergreen foliage clump. Cut old flower culms to the base in late winter. Cool-season grass. Non-toxic. Deer-resistant. Drought-tolerant. Zones 6-9.

Pruning

Cut old flower culms to the base in late winter (February-March). Do not cut the evergreen foliage clump. Comb out dead foliage with gloved hands. Division rarely needed and resented — the deep roots make division difficult.

Pruning Schedule

early spring

Maintenance Level

very low

⚠️ Toxicity Warning

Non-toxic