Caltha palustris is more commonly called marsh marigold or kingcup. This wonderful plant thrives across our watery landscapes. It is a spectacular looking herbaceous perennial that reaches a height of 1 to 2 feet and equal width. It produces mounds of light green, rounded leaves, with scalloped edges that emerge very early in spring. Leaves will range in width from 3 to 7 inches. The foliage quickly yields to clusters of bright yellow flowers with 5 to 6 petals arranged in a cyme, each flower is roughly the size of a quarter. Flowers first appear in April and extend into June. The flowers resemble those of the buttercup. The flowers will bloom continually for one or two weeks before they develop mace-shaped fruits. Each spike of this fruit is an individual seed capsule that, when dry, it explodes, catapulting seeds. Marsh marigold emerges early in spring, blooms, and sets seed in spring before entering dormancy with the heat of the summer.
Marsh marigold is an excellent garden plant for moist, rich borders and naturalized and woodland gardens. The plants are wonderful in bloom and if watered adequately, planted around water features, or planted in a bog like area the foliage will hang on through mid-summer.
If you have planted in the right area your marsh marigold will form foot-tall mounds of foliage topped with 1- to 2-inch-wide yellow blooms in early spring. It’s also an excellent selection for chronically soggy or poorly drained sites. It will go dormant after it blooms, especially if it is stressed by heat and the soil is allowed to dry.
This wildflower is common in swampy areas and along stream banks. Marsh marigolds thrive when it grows just above the water. During their dormant period the soil should not be allowed to dry at all. Marsh Marigolds are a welcome sight in early spring but seem to disappear as fast as they emerged. They transplant well but going into the spring muck to dig them up cannot be described as easy, but adding Marsh Marigolds to a water garden is well worth the effort.
Plant It With
Siberian iris can also grow in wet soils in sun or partial shade. Its grassy foliage contrasts nicely with marsh marigold.
Hardy hibiscus needs full sun and appreciates wet soil. It is slow to start growth in the spring, so marsh marigold steals the show until hardy hibiscus takes over when the marsh marigold goes dormant.
The grass like foliage of rush is perfectly at home in standing water. For extra fun, combine marsh marigold with curlicue spiral rush.
Light: Sun to partial sun
Hardiness Zones: Zone 2 to 8
Plant Type: Perennial, water/bog plant
Plant Height: 12 to 15 inches
Plant Width: 12 to 15 inches
Landscape Uses: Beds & borders, areas that do not drain well
Special Features: Flowers, tolerates wet soil
Soil pH: Neutral
Bloom Time: April to June
Flower Colors: Yellow
Transplants: Easily tolerates transplanting