Masterwort

Sun

Partial shade, especially afternoon shade in warmer areas; full sun where summers are cool and the soil stays moist.

Water

Keep the soil evenly moist but not waterlogged; water deeply during dry spells.

Soil

Humus-rich, moisture-retentive soil with good drainage; tolerates clay, loam and a range of soil pH.

Height

1.5-3 ft (0.45-0.9 m)

Spread

1-2 ft (0.3-0.6 m)

Flowers

Late spring through summer, sometimes repeating into early autumn; tiny white or pink flowers surrounded by greenish-white, pink or red-toned bracts, depending on the cultivar.

Foliage

Basal clumps of green, palmately divided leaves with toothed edges; smaller leaves occur along the upright flower stems.

Growth

Moderate

Care needed

Medium

• Pollinators
• Cold hardy
• Low allergen

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Moderate

Toughness

Fairly tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   1 ft (0.3 m)

2. After 1 year

   1.4 ft (0.43 m)

3. After 2 years

   1.8 ft (0.55 m)

4. After 3 years

   2.2 ft (0.68 m)

   full size

About 3 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Growth rate

Moderate

• Water during dry spells before the root zone dries out completely.
• Apply compost and a moisture-conserving mulch in spring, keeping mulch clear of the crown.
• Feed lightly in spring only if growth is weak or the soil is poor.
• Divide crowded clumps in spring or early autumn, watering divisions until established.
• Remove unwanted seedlings while small; they may not match the parent plant.

Pruning. Cut spent flower stems back to the basal leaves to limit self-seeding and encourage another flush of flowers. Remove dead foliage in late autumn or before new growth starts in spring.

Early spring

Remove old foliage and check for slugs around emerging shoots.

Spring

Plant or divide clumps, then water well and mulch with compost.

Late spring

Begin watering during dry weather, particularly in sunny borders.

Summer

Cut flowers for arrangements and remove fading stems to encourage repeat flowering.

Early autumn

Plant or divide while the soil is moist and there is time for roots to establish before winter.

Late autumn

Remove collapsed foliage and any remaining seed heads if seedlings are unwanted.

• Plant in small groups through a partly shaded border, where the fine flower heads soften larger leaves.
• Combine with ferns, hostas and hardy geraniums along a woodland edge with moist soil.
• Weave among roses in cool, well-watered borders to fill gaps beneath their flowering stems.
• Use pale-flowered forms in white or pastel planting schemes, with dark foliage nearby for contrast.
• Include in a cutting border for fresh arrangements and dried flower heads.

Garden styles it suits: Cottage garden, English country, Woodland, New perennial (prairie), Romantic rose garden and Pollinator garden.

Plant it with: Hardy geraniums, Hostas, Lady's mantle, Astilbes, Japanese painted ferns and Roses.

Wildlife: The accessible flower heads attract bees, hoverflies and other pollinating insects.

• Slugs and snails can damage emerging leaves: inspect young growth and use hand removal or locally approved iron-phosphate bait as needed.
• Powdery mildew may develop in dry, crowded conditions: water the root zone, improve spacing and remove badly affected foliage.
• Leaf scorch and early summer dormancy can follow heat or drought: provide afternoon shade, mulch and maintain steady moisture.
• Crown or root rot can occur in waterlogged soil: improve drainage and avoid planting the crown too deeply.

Not known to be toxic to people, cats, dogs or horses. No specific poisonous part is established, but it is not an edible plant and animal safety information is limited.

• Largest masterwort (Astrantia maxima)

  Usually has larger, pale pink flower heads with broad bracts and leaves divided into three main lobes; Astrantia major usually has more deeply divided, five- to seven-lobed leaves.

Astrantia refers to the star-like arrangement of the flower bracts, and major means larger.

Propagation. Divide established clumps in spring or early autumn to preserve a named cultivar. Sow fresh seed outdoors in autumn; a period of cold often helps germination, which can be slow and uneven. Seedlings may differ from the parent.

Accepted botanical name

Astrantia major

In the US and Canada

Introduced in St. Pierre and Miquelon.

Native range

Albania, Austria, Belarus, Bulgaria, Czechoslovakia, France, Germany, Greece, Hungary, Italy, North Caucasus and Poland.

Measured

Soil pH 6.5 to 7. Average height 40 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.