Place Blue Oat Grass beside a Path or Patio, and Its Cool Blue Mounds Quietly Lift the Stonework without Ever Clamouring for Attention.

Cool Blue Foliage In Neat, Upright Fountains

Helictotrichon sempervirens, usually known as blue oat grass, forms dense, upright clumps of steel‑blue leaves that look like elegant fountains frozen mid‑splash. The foliage colour holds beautifully through much of the year, giving that sought‑after blue note without needing acid soil or constant pampering. Each plant makes a tidy dome, with leaves arching outwards but never sprawling. In a mixed border, that cool blue contrasts gently with greens and warms up beautifully beside brick, gravel or paving. It’s the sort of grass that instantly makes a planting look more deliberate and composed.

  • Cool Blue Foliage In Neat, Upright Fountains
  • Airy Oat‑Like Flowers For Extra Height And Movement
  • Tough, Low‑Maintenance Grass For Sunny, Free‑Draining Spots

Helictotrichon at a Glance:

Common name: Blue oat grass

Latin name: Helictotrichon

Plant type: Clump‑forming evergreen or semi‑evergreen perennial grass.

Size in UK gardens: Typically around 40–60cm tall in foliage, with flower stems reaching roughly 80–120cm, and a spread of about 40–70cm once established.

Best position: A sunny, open spot with good drainage – ideal for gravel areas, front‑of‑border planting and sunny banks.

Soil: Poor to moderately fertile, neutral to alkaline, well‑drained soil; dislikes heavy, waterlogged ground.

Main interest: Steel‑blue foliage in tight clumps, plus airy oat‑like flower stems in early to midsummer, and strong winter outline.

Fragrance: Not noticeably scented – grown for foliage colour, structure and movement.

Hardiness: Hardy in most UK gardens; rated H5, so should cope with severe winters in much of the country if drainage is good.

Care level: Easy – low‑maintenance once established, needing only occasional watering in very dry spells and a yearly tidy‑up.
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Helictotrichon Care at a Glance:

Planting time: As container‑grown grasses, Helictotrichon can be planted in most months when the ground isn’t frozen or waterlogged; spring and early autumn are usually easiest, giving roots time to establish before extremes of heat or cold.

Watering: Water regularly in the first growing season so the rootball and surrounding soil don’t dry out completely, especially in very free‑draining beds or raised planters. Once established, blue oat grass is quite drought‑tolerant in the ground and usually only needs help in prolonged dry spells.

Feeding: Blue oat grass is not a hungry plant. In most gardens, a light mulch of compost or fine gravel in spring is enough. Avoid heavy feeding, which can push soft, floppy growth and dull the foliage colour.

Pruning: In late winter or very early spring, comb or trim out dead leaves and old flower stems, taking care not to cut hard into the crown. Every few years, older clumps that have thinned in the middle can be lifted and divided or replaced.

Winter: In well‑drained soil, Helictotrichon usually sits through winter with its clump intact, sometimes bleached but still clearly structural. Good drainage and a modest mulch are far more important than fleece or elaborate protection.

Varieties We Usually Stock

Availability is always changing, so please check with us if you have a particular variety in mind.

Acer campestre

Acer campestre 'Elsrijk'

Acer campestre 'Queen Elizabeth'

Acer campestre 'Carnival'

Frequently Asked Questions

Most blue oat grass plants form clumps around 40–60cm tall in foliage, with flower stems reaching up to roughly a metre or so in good conditions, and a spread of about 40–70cm. That’s substantial enough to be useful, but not so large that it overwhelms a typical suburban border. If your space is tight, simply allow for one mature plant every 60–70cm or so, and don’t crowd it with taller perennials right on top of it. In small gardens, a few well‑spaced clumps can comfortably edge a bed or path without feeling overbearing.

Helictotrichon will tolerate a little light or dappled shade, especially in the afternoon, but it really does its best work in full sun. In a bright position the clumps stay tight and upright, and the foliage colour is at its coolest and clearest. In heavier shade, plants often become looser, the blue tones soften, and flowering can be reduced. If your garden has mixed light, try to reserve the sunniest, most free‑draining places for blue oat grass and use more shade‑tolerant plants in deeper shade.

It’s possible, but it takes a bit of groundwork. Blue oat grass dislikes sitting in cold, waterlogged soil over winter, which is exactly what unprepared clay tends to provide. If you’re on clay, it’s worth improving a generous area with lots of well‑rotted compost and some grit to open the structure, then planting slightly high so the crown sits above the wettest level. Alternatively, consider raising the planting area in a low mound or using Helictotrichon in a raised bed or large container of free‑draining compost. Once drainage is sorted, the grass itself is fairly forgiving.

In decent conditions, a clump of Helictotrichon will look good for several years, often longer, before the centre begins to tire. To keep it smart, give it a light tidy in late winter or early spring, removing dead foliage and old flower stems. Every few years, if the middle has thinned out or died back, you can lift the plant, split off healthy outer pieces and replant them, discarding the worn‑out centre. In busy gardens, some people simply replant with fresh young plants when clumps start to look past their peak – either approach works, and the grass responds well to a gentle refresh.