Plant of the Month: August
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Stipa gigantea
Common name: golden oats, giant feather grass
Family: Poaceae
Vital statistics
Height and spread: up to 2.5m (8ft) high and 1.2m (4ft) wide
Form: Perennial grass
Soil: Moderately fertile, medium, well-drained soil
Aspect: Full sun
Hardiness: Hardy throughout the British Isles |
Combined with other grasses, Stipa gigantea stands tall at the back of the mixed perennial and grasses border with its huge heads of harvest yellow flowers. Waving around like corn in the fresh breezes of Harlow Carr this wonderful sight lasts from mid summer until the stems are blown down by the strong winds of winter in late December or January.
Situated opposite the Alpine Houses, surrounded by sinks and troughs, the mixed perennial and grasses border was planted in 1999 and designed to give flower or foliage effect for approximately 10 months of the year. Spring bulbs such as Tulipa species and Narcissus 'W. P. Milner' start the year followed by the blue and white forms of Cammasia and Allium mixed with herbaceous perennials such as Agapanthus, Aster, Aconitum, Dierama, Kniphofia, Sedum, Schizostylis, Thalictrum and Verbena along with grasses like Calamagrostis, Cortaderia, Miscanthus, Molinia, Panicum and Pennisetum.
Genus Stipa
Stipa is a genus of about 300 species of evergreen or deciduous grasses inhabiting open woodlands, stony slopes and steppes world-wide but mainly from temperate and warm-temperate regions in New Zealand, Europe, Asia and the Americas.
Only a few species are commonly grown in gardens, the majority of these are shorter than S. gigantea and are grown for their soft, feathery inflorescences, particularly S. tenuissima.
Stipa tenacissima, esparto grass, sometimes grown in gardens, is also grown commercially for paper making, including cigarette papers.
The name Stipa comes from the Greek word stuppe meaning tow, from the feathery inflorescences.
Stipa gigantea
Stipa gigantea is one of the largest feather grasses and is said to be one of the most magnificent of all the ornamental garden grasses. It's narrow (3mm) leaves form a large tuft of basal foliage while the loose, open panicle flowers are held high above the foliage on stems 2.5m high during June to August and persist well into the autumn and winter months.
The specific epithet gigantea appropriately describes the tall stems while the common name golden oats accurately describe the oat-like panicles of flowers which are golden when ripe.
A native to Spain, Portugal and Morocco it happily grows in Britain and northern Europe though it will not survive the winter in waterlogged conditions.
AGM
The RHS Floral Committee A awarded Stipa gigantea an Award of Garden Merit and described it as:
'Robust tufted evergreen perennial to 2m, with arching linear green leaves and large panicles of oat-like, long-awned purplish flowers which ripen to gold.'
Cultivation
Stipa species and cultivars are all easily grown in any moderately fertile, well-drained soil in full sun. Most are hardy to at least -15°C though many will not survive the winter in conditions where the soil is waterlogged.
Plants should establish quickly and once growing well need little attention apart from cutting back of the foliage during the winter to tidy it up before the new flush of growth appears in the spring. Once established Stipa gigantea is drought resistant.
Stipas are not troubled by pests or diseases.
Propagation
Stipa can be propagated from seed or division. Sow seeds in container in a cold frame in spring, or divide plants in mid-spring or early summer.