Giant Marsh Marigold / Giant Kingcup (Caltha polypetala) - Marginal for Shallow Edges (Peat-Free, Pesticide-Free)

Bigger, bolder and earlier than the common Marsh Marigold, Giant Kingcup delivers large golden saucer flowers over lush, heart-shaped leaves in early spring, lighting up the shallow shelf and boggy margins. Clump-forming growth steadily knits and stabilises soft edges, creating safe cover for emerging amphibians while drawing in early hoverflies and small bees to its open nectaries. Expect around 40-80 cm in height when established, with a 30-60 cm spread. Best at the pond margin with 0-10 cm of water over the soil, or in reliably damp ground just outside the liner. (This is a garden form of our native Marsh Marigold - chosen for size and show; treat it as a cultivar/variety of a native species.)

Where it thrives

• Light: Full sun to partial shade (flowering is strongest with good light)

• Moisture/Zone: Pond margin / bog; set the basket so there’s 0-10 cm water above the soil, or plant in consistently damp soil at the edge

• Companions: Pairs beautifully with Water Mint, Brooklime, Lesser Water Plantain and sedges for layered wildlife habitat

Planting & care

• Plant in a mesh aquatic basket with peat-free aquatic compost; top with washed grit and set on the shallow shelf

• Deadhead after flowering to keep plants tidy; remove old leaves in late winter to make way for fresh growth

• Divide clumps every 3-4 years if crowded; re-set divisions at the margin for quick re-establishment

• Allow only modest self-seeding if you want a natural look; lift extras easily from gravel

Safety (important & honest):
As a member of the buttercup family, sap can irritate skin/eyes; wear gloves when dividing or trimming. Do not ingest. Keep clippings and soil out of natural watercourses; never release garden plants into the wild.

Truth-first wildlife note:
A superb early nectar source and edge cover plant, but like all “wow” forms, it’s best combined with other single-flowered natives to offer continuous forage and shelter through the season.

Joel says…
“For that first blast of spring gold at the water’s edge, the Giant Kingcup is hard to beat. Basket it shallow, give it light, and let it knit a sturdy, wildlife-friendly rim around the pond.”

If you are using Joel’s methods, as referenced in the ‘Wild Your Garden’ book and on Joel's Youtube channel, appropriate marginal plants can be planted in the sub-soil areas around the edge of the pond. In these cases, you will not need to “re-pot” your 9cm pots, as they will go straight into the sub-soil.

However, if you are not using sub-soil and are going for a more formal look, the 9cm pots should be re-planted into an appropriate 1l size container or otherwise before being placed in or around your pond.
Container grown marginals should be placed in trays of water so that their roots may absorb the moisture. All sizes and planting depths are a guide only and considerable variation in the depth of water over the soil will be tolerated by most aquatics.

All plants in 1 litre containers and larger are in their final mesh basket and do not require repotting. However, we recommend 9cm plants are re-potted up to a minimum of 1 litre.

IMPORTANT NOTE: If you are ordering perennials between the months of October and March, including aquatic plants, please be aware that this is the dormant phase for perennials, so your plants may arrive showing potentially little or no top growth at this stage, or can in some cases still have some old leaves from last year showing also. Please don't worry, as this is all quite normal. Once the weather warms up in spring, you will start to see fresh growth and activity! If you ever have any concerns at all, please just message the team on enquiries@wildyourgarden.com and we'll always do our best to help.