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We have combined these two powerful search tools into a single Find a Plant service searching over 250,000 plant records.
Virtually all of the features of the old searches are still available and in addition we have added several new features to create a more comprehensive and user friendly search experience.
When using this search
Search by plant name, key attributes or both to find plant details and a list of
AGM plants have been through a rigorous trial and assessment programme. They are:
This plant will provide nectar and pollen for bees and the many other types of pollinating insects.
It is included in an evolving list of plants carefully researched and chosen by RHS experts. Divided into 3 groups these lists, linked below, are maintained by a team of RHS staff and are reviewed annually.
the RHS today and get 12 months for the price of 9
Other common names
giant marsh marigold
Caltha palustris subsp. polypetala
Caltha are rhizomatous herbaceous perennials with simple, usually heart-shaped leaves and cup-shaped yellow or white flowers in early spring
C. polypetala is a herbaceous perennial, up to 60cm high and 90cm wide, spreading by rooting stems across ground or across water. It has rounded green leaves, the basal leaves up to 10cm across, the stem leaves fewer and smaller, and shining, bright golden yellow flowers, up to 5cm across, from early spring to summer
All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets
Aspect South-facing or West-facing or East-facing
Exposure Exposed or Sheltered
SoilChalk, Sand, Clay, Loam
pHAcid, Alkaline, Neutral
Time to ultimate height
Plant from spring to autumn in full sun, in deep, rich organic soil, at the water's edge or in shallow water up to 15cm deep; mulch annually to conserve moisture
Propagate by seed, sown fresh in late summer in a cold frame, making sure that the compost does not dry out, or by division in spring
Suggested planting locations and garden types
Cottage & Informal Garden
Pruning No pruning required, though the stems may be cut back after flowering
Pests Generally pest free
May be affected by powdery mildews and rust diseases
RHS members can get exclusive individual advice from the RHS Gardening Advice team.
The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.