How to Grow Blue Oat Grass
Helictotrichon sempervirens
Blue Oat Grass forms a tight, evergreen clump of striking steel-blue leaf blades that keep their colour year-round. Plant in full sun in well-drained, even poor soil — good drainage is more important than fertility. Space plants 50-60 cm apart. Water regularly in the first season to establish; once rooted it is highly drought-tolerant and largely self-sufficient. In early spring, comb out dead material with gloved hands and trim any brown tips. Every 2-3 years cut the whole clump back to about 10 cm to rejuvenate the colour and tidy the form. Divide congested clumps in spring.
Yearly Lifecycle
Care Essentials
Rarely needed. A light dressing of balanced granular fertiliser in early spring is sufficient. Avoid rich feeding which dulls the blue colouring.
Watch For
- Rust
- Aphids on new growth
- Crown rot in waterlogged soil
Care Requirements
Light
Full sun, minimum six hours daily
Full sun is essential for the best blue colouring and compact habit. In shade the leaves turn grey-green and growth becomes floppy. Six hours of direct sun is the minimum; more is better.
Watering
Low; drought-tolerant once established
Water new plants regularly in the first season until rooted. Once established, Blue Oat Grass is highly drought-tolerant and rarely needs supplemental watering. Avoid waterlogged conditions which can cause crown rot.
Fertilizing
Minimal; light balanced feed in spring if needed
Lean soil produces the best blue colour. A light application of balanced granular fertiliser in early spring is sufficient if growth is poor. Avoid rich feeding which dulls the blue and causes lax growth.
Pruning
Comb out dead leaves in spring; rejuvenation cut every 2-3 years
In early spring, comb through the clump with gloved hands to remove dead leaf blades and trim brown tips. Every 2-3 years cut the whole clump back hard to about 10 cm above ground to restore vigour and colour.
Spacing
50-60 cm apart
Space plants 50-60 cm apart to allow the arching leaf blades to display fully without crowding. Closer spacing can be used for a mass-planting effect.
