Superb Sesleria

Seslerias are a group of practical, durable and beautiful grasses whose popularity in the UK is rapidly increasing as we come to see just how useful and effective they are in our gardens and designed spaces.

It is the foliage of these super adaptable plants that make them so useful in our gardens, and varies from shades of green through to bright almost yellow green and on to blue ish and grey. Often produced during the summer months the flowers can add considerably to the grasses appeal, but it is the foliage which is perhaps the prime quality and the number one reason for their use in so many different garden situations.

Seslerias are primarily foliaged based grasses as is elegantly demonstrated by this impressive use of Sesleria autumnalis at Sussex Prairies.

Seslerias are effective when used in a number of different ways in our gardens and designed spaces. There are some, such as Sesleria nitida for example, which are perhaps most noticeable when used individually as early season accent plants. Most however can be used in drifts and groups, and will be very effective in general planting schemes in combination with a wide choice of other grasses and perennials.

The low mounds of soft yellowish green foliage of Sesleria autumnalis make it a great practical choice for matrix style planting schemes.

Most seslerias, such as Sesleria autumnalis or Sesleria Greenlee Hybrid for example, can also be used as a matrix or a base grass in what are now often referred to as meadow style plantings. At this they excel. The happy combination of long season foliage and a mostly clumping mounded habit make sesleria well placed to act as a base and a foil in such schemes. Meadow style planting offers an enticing mix of elegant informality and low maintenance with some strikingly beautiful results.

Characterised by low mounds of effective and durable foliage, sesleria are especially well suited to matrix and meadow style schemes – such as Sesleria autumnalis used by Piet Oudolf in the newly re designed Glasshouse borders at RHS Wisley.

Seslerias are generally unfussy as to soil type. While an average to well drained soil is possibly ideal, they appear happy in a variety of heavier soils; only becoming problematic in soils where there is a high level of moisture or surface waterlogging during the winter period. They do not like boggy conditions and, like so many other plants, will be slower to establish in heavier soils.

In warmer, and drier, climates they remain evergreen but in our mild and often damp conditions sesleria are best regarded as being semi evergreen. In practice this simply means that while the plants inclination may be to retain its foliage year round by the end of the winter that foliage can look fairly bedraggled and so will take being trimmed back to a few inches or so of the base any time from early spring onwards.

Sesleria nitida is valued for its combination of stiff blue ish grey foliage and dainty looking early season white flowers.

While all sesleria prefer a sunny and generally open position some seem able to tolerate a certain level of shade. The open shade such as cast by buildings and fence lines is not an issue for most, while some such as Sesleria autumnalis has shown itself capable of growing in reasonable proximity to larger woody plants, and their thirsty root systems. However flowering and longevity can be significantly reduced under such situations. In common with most other such blue leaved plants the grey and blue foliaged forms, such as Sesleria Summer Skies, are always happiest and offer best foliage colour in full sun.

As with all blue foliaged plants best colour, and flower, is always achieved in sunny, dry and open conditions – such as with Sesleria Summer Skies seen here in full summer time flower – growing in the Mill End borders and backed by the taller blue foliage of the equally drought tolerant Panicum Sea Mist.

The flowers tend to come in various shades of white and vary from slim and elongated, such as with Sesleria autumnalis, or rounded such as with Sesleria nitida. Most are produced during summer although Sesleria nitida produces spring time rounded white flowers that are especially valuable early in the season. Sesleria caerulea and Sesleria Spring Dream are compact and produce flowers on short stems which while delicately beautiful do not offer the same mass effect as the summer blooming types.

The low clump forming habit and fresh green foliage of Sesleria Greenlee Hybrid makes it an excellent choice as a base grass for matrix style planting.
Sesleria Greenlee Hybrid used as a matrix grass in a meadow style planting at Hauser and Wirth in Somerset.
Sesleria caerulea is very compact and slow growing with attractive bicoloured foliage. At the Royal Botanic Gardens Kew it has been used very effectively at the centre of the grass garden as a low level meadow or shaggy lawn.
A recent selection from Knoll Gardens, Sesleria Summer Skies offers gradually spreading mounds of impressive, relatively stiff blue grey foliage that intensifies as conditions get drier.
In a courtyard area at Hauser and Wirth in Somerset, the bright yellow green foliage and dainty silver white flowers of Sesleria autumnalis is used in effective association with an upright molinia and within the light shade of small trees.
Sesleria Summer Skies used in a matrix style planting at Knoll Gardens from which summer blooming alliums and a procession of other perennials can be seen to emerge as the season progresses.
In common with Sesleria caerulea, Sesleria Spring Dream has compact slow growing blue grey foliage and dainty early season flowers. If needed this form should be trimmed early in the year before the spring flowers start to emerge.
With a fibrous root system most seslerias, such as this Sesleria Summer Skies at Knoll, will grow well in pots provided that they are watered in dry periods and repotted when necessary to maintain vigour.
Even a coating of snow does not stop these Sesleria Greenlee Hybrid from looking pretty neat.