How to Grow Marsh Marigold — Caltha

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Caltha is a genus of about 10 species of marshland or marginal aquatic perennials. The best-known and most commonly grown Caltha is C. palustris, the marsh marigold. Caltha bears loose clusters of showy golden yellow or white flowers in spring.

Caltha flowers are usually cup-shaped; they appear before the heart- or kidney-shaped leave emerge in spring. Caltha flowers lack true petals; they have petal-like sepals.

Members of the Caltha genus are rhizomatous perennials. All are well-adapted to edges of pools, ponds, streams and other moist locations.

Flowering Marsh Marigold (Caltha palustris) on the banks of a pond
Flowering Marsh Marigold (Caltha palustris) on the banks of a pond

Get to know Caltha

  • Plant type: Perennial
  • Growing zones and range: Zones 3 to 7
  • Hardiness: Hardy to Zone 3
  • Height and width: 15 inches (38cm) tall; 15 inches (3 cm) wide.
  • Foliage: Attractive, bright green, heart-shaped leaves form foot-tall clumps.
  • Flowers: Bright yellow usually cup-shaped flowers.
  • Uses: Wet natural garden, low-lying spots where water stands, and for the edge of streams or around water gardens.
  • Garden companions: Water forget-me-not (Myosotis scorpioides), water iris, Siberian iris, and other perennials that like wet feet.
  • Common name: Marsh marigold, cowslip
  • Botanical name: Caltha
  • Family name: Ranunculaceae

Where to plant Caltha

  • Plant Caltha in full sun or light shade.
  • Plant Caltha in constantly moist to boggy soil. At the edge of a stream or pond is ideal.
  • Caltha palustris will grow standing up in water to a depth of about 9 inches, shallow water is best. C. palustris can be planted in a container set in shallow water.
  • Try Caltha in normal soil if it isn’t too dry.
Marsh Marigold, Caltha Palustris growing in stream in woodland.
Marsh Marigold, Caltha Palustris growing in stream in woodland.

When to plant Caltha

  • Sow Caltha seed in early summer.
  • Set container-grown plants in the garden in spring or autumn.

Planting and spacing Caltha

  • Space Caltha 18 inches (45cm) apart in wet soil or submerge their crowns in up to 1-inch-deep (2.5 cm) water.

How to water and feed Caltha

  • Keep Caltha continuously moist.

Caltha care

  • Caltha needs little care.

Caltha pests and diseases

  • Caltha can develop powdery mildew and rust.
  • Garden pests are not common for Caltha.

Caltha propagation

  • Divide Caltha in early spring or late summer.
  • If plants become crowded, divide them during their summer dormancy.
  • Sow seeds in spring; Caltha self-sows.
Caltha palustris
Caltha palustris

Caltha varieties to grow

  • Caltha dioneaefolia: compact, cushion-forming, marshland perennial to 2 inches (5cm) high.
  • C. introloba: dwarf, tufted, marshland perennial to 2 inches tall produces large almost stemless white flowers in late winter.
  • C. leptosepala, alpine marsh marigold: marginal aquatic perennial grows to 12 inches (30cm) high and wide; bears white flowers often in pairs.
  • C. palustris, marsh marigold, kingcup: marginal aquatic perennial grows 4 to 16 inches (10-40cm) tall and 18 inches wide; stems grow 12 to 18 inches tall and bar waxy yellow flowers to 1.5 inches across; may grow in water to 9 inches deep; cultivar ‘Flore Pleno’ has double yellow blooms; it’s an outstanding double form with 2-inch (5cm) yellow flowers. 10 inches (25cm) tall.

Written by Stephen Albert

Stephen Albert is a horticulturist, master gardener, and certified nurseryman who has taught at the University of California for more than 25 years. He holds graduate degrees from the University of California and the University of Iowa. His books include Vegetable Garden Grower’s Guide, Vegetable Garden Almanac & Planner, Tomato Grower’s Answer Book, and Kitchen Garden Grower’s Guide. His Vegetable Garden Grower’s Masterclass is available online. has more than 10 million visitors each year.

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