Sesleria: Planting, Growing and Care

Description and botany

The Sesleria is a small species of low-growing perennial grass belonging to the Poaceae family. The genus comprises 33 species native to mountainous regions or dry or moist meadows of Central, Eastern and South-Eastern Europe, including several perennials such as Sesleria automnalis, which flowers late in the season. Other varieties found in our gardens include Sesleria caerulea or blue moor grass, Sesleria argentea or silver moor grass, and Sesleria heufleriana, all fully hardy, tolerant and perfectly adapted to all our climates.

Sesleria caerulea (left), botanical plate from 1903

This clump-forming grass, meaning non-running, creates a small herbaceous and bushy mound reaching 30 to 70 cm in all directions when in flower. It establishes slowly but proves very long-lived once well-rooted. The habit is both bristly and somewhat loose, more or less spreading, always graceful and airy.

The fine foliage is evergreen, making this grass attractive even in winter. It consists of alternate, single, narrow and linear leaves. Measuring 15 to 50 cm long and 2 to 7 mm wide, tapered and acute, they are folded into a “V” shape or marked by parallel veins. They display varied colours depending on the species, ranging from pale green, yellow-green to light green or even glaucous green or grey-blue.

The foliage is marcescent, drying but persisting through winter, taking on lovely muted tones.

From this gramineous vegetation, flowering emerges from May to August depending on the species and variety. The autumn moor grass flowers in late summer until October. This flowering takes the form of feathery, cylindrical or elongated spikelets. These tubular floral spikes resemble fine brushes. They consist of anise-green and white, greenish-white, silvery-white or even blue-black flowers. These delicate inflorescences remain elegant throughout the off-season, drying in autumn and often darkening as they fade.

Sesleria automnalis and Sesleria heufleriana (© Andrey Zharkikh). Right, Sesleria caerulea (© Wikimedia Commons-Stan Shebs)

Main species

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Planting

Where to Plant It?

Perfectly hardy (sometimes down to -25°C in well-drained soil), Sesleria is a mountain native that thrives everywhere, in the north as well as the south of France, in lowlands as well as mountains, or by the seaside.

Not being a demanding perennial, it will be content with almost all types of soil, dry to moist, neutral to calcareous (except acidic soils) but above all well-drained in winter. It does not tolerate heavy, water-retentive soils that suffocate its roots. A rather dry soil will suit it perfectly. It adapts well to poor, rocky soil. It can be planted in full sun or partial shade.

This non-invasive plant fits into all gardens, in small spaces, along pathways, or to structure a natural area when planted en masse. It is also interesting for creating dry meadows in natural gardens or green roofs. Its infinitely light foliage adapts to all settings. In a contemporary-style garden, it will highlight all perspectives. It also makes an excellent ground cover solution for difficult areas, even in shade. It also works well in flowering pots or planters.

When to Plant It?

Planting Sesleria is preferably done in spring from February to April for quick establishment. Autumn planting from September to November is also possible. In all cases, avoid planting during frost or extreme heat periods.

Sesleria automnalis (© Andrey Zharkikh)

In the Ground

Plan for 4 to 5 young plants per m², spacing them 30 to 60 cm apart. It looks best when planted in groups of 5 to 10 plants for a beautiful mass effect or to create a light yet full pathway border.

It must be planted in well-draining soil that does not retain stagnant water in winter. In heavy soil, add a spadeful of gravel, some compost, or river sand as this pretty little herb needs well-drained soil.

• Work the soil thoroughly to a good depth
• Plant in a hole 2 to 3 times the volume of the bucket
• Loosen the extracted soil well
• Spread gravel or clay pebbles at the bottom of the hole to aid drainage
• Place the rootball in the centre of the hole
• Fill with garden soil mixed with 1/3 compost and coarse sand
• Firm down and water generously

In Pots

Ensure the substrate is very free-draining. Choose a container at least 50 cm in diameter with drainage holes.

• Add a drainage layer
• Plant in a mix of 1/3 universal compost and 2/3 coarse sand
• Water

Maintenance, pruning and care

While Sesleria proves very undemanding once well-rooted, during the first year after planting, you’ll need to ensure regular but not excessive watering, especially during periods of intense heat or prolonged dry weather. It requires more water if conditions are too dry. Once established, it will show greater resilience to short periods of drought. In winter, it will make do with rainwater alone.

Mulching (with pale of flax, dry leaves, etc.) at the base of the plant will reduce evaporation in summer and thus limit the need for watering.

A light application of organic fertiliser twice a year during the growing season—particularly if the soil is very poor—will encourage growth.

In February-March, before new growth resumes, trim the clump back to 10 cm above the soil using hedge shears to make way for fresh foliage.

In pots

Specimens grown in pots will require more frequent watering, especially during very hot and windy weather. Repot as needed, roughly every two years. Alternatively, you can simply refresh the top layer once a year by replacing the old compost with fresh, to a depth of a few centimetres. There’s no need to store pots away in winter, though a sheltered spot protected from winter rains is advisable.

Propagation

Dividing clumps of Sesleria is an excellent way to perpetuate the plant. It’s best done in spring, on a well-rooted young plant, after 3 to 4 years of cultivation.

• Using a garden fork, gently lift the clump
• With a spade, divide the clump into 2 or 3 sections
• Select vigorous divisions with sufficient roots
• Replant the divisions immediately in well-prepared soil
• Water thoroughly

Pair with

Sesleria is ideal for small or large sunny spaces, even in dry soil during summer. This wild little herb easily finds its place in a natural garden, as well as in the more refined setting of a contemporary garden and graphic garden, or in a dry or gravel garden.

In a dry rockery, it pairs well with other small ornamental grasses like Festuca glauca ‘Golden Toupee’, thymes, autumn stonecrops, or small Helianthus.

Sesleria can be planted along pathways. For companion planting, consider other compact, non-spreading grasses such as Pennisetum alopecuroides ‘Hameln’ or Pennisetum alopecuroides ‘Cassian’.

In a naturalistic border, it serves as a punctuation plant alongside other summer-flowering perennials. Pair it with Achillea filipendulina ‘Golden Plate’, lavenders, or asters. It helps lighten the appearance of heavier-flowering perennials like coneflowers or Oriental poppies.

In a naturalistic setting like naturalistic meadows, you can combine it with other ornamental grasses such as fountain grass, Calamagrostis brachytricha or Diamond Grass, or Stipa tenuifolia – together they create texture and movement.

In a minimalist, contemporary design, pair it with Phyllostachys aureosulcata ‘Aureocaulis’, a strikingly luminous bamboo variety, and a tall wild grass like Panicum virgatum ‘Blue Darkness’ with its variegated purple-black and blue-green foliage.

→ Discover 7 more companion planting ideas with Sesleria

Centre: Sesleria automnalis, accompanied by yarrows, poppies, lavenders, coneflowers and Aster ericoides ‘Blue Wonder’