Great masterwort

Botanical data

Family

Apiaceae (Apiaceae)

Height

0.4–0.9 m

Width

0.3–0.5 m

Habit

Clump-forming

Growth rate

Slow

Position

Partial shade, Full sun

Soil

Humus-rich, Loamy, Chalky

pH reaction

pH 5.5–7.5

Moisture

Moist, Moderate

Bloom

June–September

Hardiness

USDA 4a–8a

Propagation

By division, From seed

Characteristics

A perennial forming a dense clump from a short, thickened rhizome, without runners — it spreads slowly and stays where it is planted. The basal leaves are palmately lobed or palmately divided, with 3–7 crenate-serrate segments, dark green, borne on long stalks; they form a low rosette 30–50 cm across. From the rosette rise stiff, sparingly branched flowering stems 40–90 cm tall, with a few sessile stem leaves. The inflorescence is a simple umbel 2–3 cm across, made up of several dozen tiny flowers — an exception in a family for which compound umbels and pinnate leaves are the rule. The star effect comes not from a corolla of flowers but from the ruff of a dozen-odd stiff, pointed, almost papery bracts 1–2 cm long surrounding the umbel: in the type they are greenish-white with pink or purple veining, in the cultivars uniformly pink, carmine or deep red. The bracts stay ornamental for many weeks — hence the impression of a very long bloom. The fruit is a schizocarp that splits into two mericarps with scaly, wrinkled ribs. It blooms from June to September: the first flush in summer, a repeat one after the spent stems are cut back. It grows in partial shade and in sun — provided the soil stays moist — on fertile, humus-rich, firm, water-retentive ground. It tolerates a wide range of pH, from slightly acid to alkaline — in the wild it most often grows on limestone soils, but it also copes on lime-free ones. It handles drought poorly: first the leaf-blade margins dry out, then the whole rosette dies back prematurely. With frost it is the reverse — the clumps overwinter without protection in zones 4a–8a and cope worse with a hot, dry summer than with a hard winter. Great masterwort is distinguished from Astrantia maxima, which has three-parted leaves, larger and uniformly pink bracts and spreads by runners, and from the smaller mountain species with narrower ruffs: Astrantia minor and Astrantia carniolica.

Popular cultivars

‘Roma’

Selected by the Dutch designer Piet Oudolf, with clean pink bracts and 50–70 cm tall. It sets practically no seed, so it does not self-sow and flowers exceptionally long. Propagated only by division.

‘Claret’

Deep-red, wine-coloured bracts and almost purple stems; about 50–60 cm. The colour is deepest in partial shade — in harsh sun it fades towards pink more quickly.

‘Ruby Wedding’

One of the darkest reds in the species, with ruby bracts and dark stems, about 50–60 cm. Grown from seed it gives seedlings much paler than the parent plant, so it is kept only from division.

‘Shaggy’

Bracts exceptionally long, narrow and unevenly cut, white with green tips — the ruff therefore looks ragged; 60–90 cm. In the trade it is sometimes sold as 'Margery Fish', after the English gardener who popularised it.

‘Sunningdale Variegated’

Grown mainly for its leaves: in spring broadly margined with creamy yellow, in summer gradually turning green. Flowers white-pink, height 50–70 cm. The variegation colours up best in bright partial shade; in deep shade it fades away more quickly.

‘Star of Billion’

From the Dutch 'Star of…' series, with clean white bracts and strong, long-flowering stems, about 60–70 cm. Good as a lightener in darker combinations and for cut flowers.

Growing and care

Companion plants

The evidence level indicates whether the relationship is backed by research, observation, or gardening tradition.

Diseases and pests

Toxicity

History and origin

The species was described by Carl Linnaeus in his work "Species Plantarum" of 1753. Its natural range covers the mountains and foothills of central and southern Europe — from the Pyrenees and the Alps through the Carpathians to the Balkans — and reaches east to the Caucasus; there it grows in moist mountain meadows, tall-herb communities and on the edges and in the clearings of beech woods. In Poland it is a native species: it occurs in the Carpathians and the Sudetes and on scattered upland and lowland sites. The genus name is usually derived from the Latin astrum, meaning star — a reference to the star-shaped ruff of bracts; a second hypothesis links it to the medieval herbalist name magistrantia, from which the English masterwort also comes. The German Große Sterndolde means literally "large star umbel". In old herbalism the root was used as a purgative and diuretic; modern phytotherapy does not use it. The masterwort owes its garden career to two waves of fashion. In the mid-20th century it was made famous by Margery Fish, the English gardener of East Lambrook Manor — to this day the cultivar 'Shaggy' is sometimes sold under the name 'Margery Fish'. The second wave came in the 1990s with the New Perennial movement and the naturalistic borders of Piet Oudolf, who selected the long-flowering cultivar 'Roma', which sets practically no seed. Since then breeding, chiefly Dutch, has produced cultivars with deep-red bracts and variegated leaves, including the 'Star of…' series.

Uses

The masterwort is one of the staple perennials of naturalistic and cottage gardens, of partial-shade borders and woodland edges. It is planted in groups of 5–7 at a spacing of 35–45 cm; at 40–90 cm tall it fits the middle plane of the border, but thanks to the airy structure of its inflorescences it also works right by a path, where the detail of the ruff can be seen. It classically accompanies roses in English gardens, but only where the soil beneath the shrubs stays moist. It combines well with lady's mantle, hostas, astilbes, coral bells and cranesbills, with clump-forming ferns, and among grasses with purple moor grass and tufted hair grass. It is not suited to dry, hot and wind-exposed sites, nor to containers — soil in a pot dries out faster than this perennial tolerates. It is also worth keeping away from plants that spread by runners, such as ostrich fern or ground elder, which within a few seasons will smother the slow-growing clump. The masterwort self-seeds freely, and the seedlings of coloured cultivars revert to the greenish-white type, grow more vigorously and after a few years displace the choice cultivar — this is prevented by cutting back the spent stems before they set seed and by weeding out the young seedlings; the cultivar 'Roma', which sets practically no seed, does not have this problem. For cut flowers the stems are cut when most of the flowers in the umbel are open; they last a long time in a vase. For drying they are cut in full bloom and hung with the inflorescences down in airy shade — the bracts keep their shape and much of their colour. Dried umbels left over winter give the border structure right through to early spring.

Trivia

• What looks like a single flower is in reality a whole inflorescence: several dozen tiny flowers surrounded by a ruff of bracts. The bracts do not fade along with the flowers, so the inflorescence stays ornamental long after pollination.
• The masterwort's umbel has flowers of two kinds: those on the rim are exclusively male, the inner ones are bisexual.
• Within the carrot family the masterwort is a double exception — it has a simple umbel instead of the typical compound umbel and palmately lobed leaves instead of pinnate or finely divided ones.
• The flat, easily accessible flowers are visited not only by bees but also by hoverflies and small parasitic wasps — insects whose larvae eat aphids, so a clump of masterwort acts as a canteen for the natural enemies of pests.

Frequently asked questions