Caltha palustris ssp. polypetala: giant marsh marigold, kingcup
Forsythia, crocus, narcissus, mahonia, acacia, kerria: have you ever pondered why so many early flowering plants have predominantly yellow flowers? It’s because the colour yellow, whether it be primrose, golden, saffron or lemon, is highly effective in attracting pollinating insects, especially in the low light levels we experience at the beginning and end of each year. (Birds’ vision is also particularly sensitive to yellow, which may be why the sparrows nip all the flower buds off my Rosa banksiae “Lutea”). The number of flying insects is particularly low during the colder months, so early flowering plants have developed boldly-coloured, weather-resistant flowers to increase their chances of attracting insects.
Lighting up the corner of the pond in our London garden is Caltha palustris spp. polypetala, a large-flowered variation on the common marsh marigold. Every year it increases in size, blessing us with tens of large, glossy, reflective flowers. Understandably bees adore the single blooms, their golden stamens lagged in pollen. I love them too, set against the dark garden wall, viewed from the kitchen worktop where I write this blog.
Despite appearances the giant marsh marigold is not native to the UK, hailing from the mountainous regions of Turkey. Our plant grows in semi-shade in shallow water, but would be equally happy at the waters’ edge. It is one of the first plants to bloom each spring, alongside the magnolia, kerria and Narcissus “Jack Snipe”. If cut back hard after flowering there will be more flowers in autumn. Provided one has a good patch of continually damp soil Caltha palustris spp. polypetala will grow without intervention, spreading to create luscious mounds of emerald-green foliage studded with flowers. Pure gold.