Ranunculus, also known as the buttercups, is a huge genus of around 400 species. Arguably best known as an annoying lawn or garden weed, there are some lovely flowers among the genus nonetheless. They can be annual, biennial or perennial herbs, and some are submerged aquatics.
The well-known wild flowers considered weeds in a garden situation are the meadow buttercup, R. acris, and the creeping buttercup, R. repens. However, both species have been selected from to provide attractive varieties such as the double yellow-flowered R. acris ‘Flore Pleno’ Award of Garden Merit (AGM) and the tall double-flowered R. repens ‘Flore Pleno’. The latter will cross with the single weedy species though, so be careful.
Another similarly named variety — perhaps someone got bored of naming ranunculus varieties — is
R. aconitifolius ‘Flore Pleno’ AGM, also known as the fair maids of France. It bears white, multi-petalled flowers with green centres.
Our native lesser celandine, R. ficaria, is another lovely flower found in woodlands and on roadsides, but in a garden situation can be a nuisance spreading by tubers. But many cultivars of this species are available, notably the dark-leaved ‘Brazen Hussy’, and are better behaved than their parent and offer quite a wide range of leaf and flower forms. This species has now been reclassified as Ficaria verna but I have included it in this article for thoroughness because it still goes under its synonym.
Cultivars of the wild flower species mentioned like the conditions in which their parents are found — damp places in sun or part shade such as woodland, mixed borders or water gardens. There are some species, however, such as the choice and less invasive plants R. parnassifolius and R. alpestris that can be grown in a sunny rock garden and well-drained soil as long as their roots are given plenty of water.
There are some nice alpine species, such as the tall R. lyallii from New Zealand, also known as the Mount Cook lily. This is a bit tricky to grow, needing a peaty, stony soil in full sun. A more challenging alpine such as R. haastii is probably best grown in the alpine house, potted into a gritty mix with added leaf mould.
The frost-tender R. asiaticus and its cultivars are beloved of florists for their single or double flowers in a range of colours including deep-crimson, orange, yellow, white and pink. The flower heads can be packed with petals, making them resemble a cabbage rose.
They are divided into two groups. The Persians are neat, shapely plants with well-formed flowers while the Turbans are larger-flowered, coarser plants but less susceptible to frost. Florists like them because they last a week or more once cut. They need the opposite conditions to the European buttercups, liking good drainage and full sun. They are best grown in pots, then overwintered in a greenhouse and brought out once warm enough to flower outside.
What the specialists say
David Sheals, owner, Summerdale Garden Nursery, Cumbria
"Ranunculus is a wonderful diverse genus, known for the charm of its simple buttercup-like flowers. Our native lesser celandine, R. ficaria, is a cheerful sight in spring with its shiny buttercup yellow flowers. However, its ability to spread from tubers makes it unwelcome in most gardens, but if your gardening is relaxed then only a transient irritant.
"There are, however, many interesting varieties providing a range of interesting flowers and leaf forms without the invasive tendency. Like the common native they will thrive in moist soils but will also tolerate drier conditions.
"The R. ficaria cultivars are easy to grow and inexpensive. The main problem of these is differentiating from the native celandine and not weeding them out by mistake. Interesting cultivars include one of the few orange-flowered ones, R. ‘Orange Sorbet’, which is a nice soft orange, and for a perhaps more discerning palette ‘Dusky Maiden’, which has green foliage attractively splashed with conker brown and nice yellow flowers."
John Winterson, deputy plant buyer, RHS Plant Centres
"Ranunculus is an eclectic genus. The RHS Plant Centres mainly sell R. ficaria ‘Brazen Hussy’ (recently changed to Ficaria verna) in early spring. Its contrasting yellow flowers against the awesome dark-brown foliage make it a popular impulse line.
"We also have a strong demand for R. aconitifolius ‘Flore Pleno’ and despite it having an AGM it is not always easy to get hold of. It has stunning, exotic-looking double flowers that are irresistible. We’ve not stocked it for a couple of years now, but hopefully it will be available again soon. R. gramineus is another pretty alpine-like plant with yellow poppy-type flowers. Again, it has not been available for a few years but sells well when we can get it.
"All are sold from both the alpine section and herbaceous section, from display tables when in flower and also among our A-Z sections."
Species and varieties
R. aconitifolius is a lovely species that produces loose showers of single white buttercup flowers
with yellow button centres on branching stems in late spring above clumps of dark-green divided leaves. Height: 91cm.
R. aconitifolius ‘Flore Pleno’ AGM (H7) is a very sought-after double form that unfortunately can be hard to find. It bears sprays of small, perfectly formed double-white buttercups with green centres on widely branched stems in early summer. Shade-loving. Height: 45cm.
R. acris ‘Flore Pleno’ AGM (H7) is a double form of the meadow buttercup. It produces almost leafless branching stems with masses of small, tightly double, bright-yellow buttercups in midsummer. Height: 91cm.
R. alpestris is a dainty alpine buttercup that produces neat tufts of dark-green foliage and small
white flowers in spring with a boss of yellow stamens. The leaves are nicely cut and have attractive veins. May flower through until the autumn. Height: 5cm.
R. ficaria ‘Brazen Hussy’ (syn. Ficaria verna ‘Brazen Hussy’) is a fantastically striking plant with dark, almost black foliage and bright golden flowers. Its foliage emerges early in the year and then dies down by the summer. A hardy and tough garden plant that is not invasive. Height: 7cm.
R. ficaria ‘Collarette’ (syn. Ficaria verna ‘Collarette’) produces bright golden yellow flowers with fully double centres and an outer ring of petals. Also has attractive marbled foliage. After flowering, the plant retreats underground. Forms neat clumps that are non-seeding. Height: 10cm.
R. ficaria var. aurantiacus, or the single lesser celandine, has orange flowers in March and April that fade as they age, leaving an orange eye at the centre. Height: 7cm.
R. illyricus forms a ground-covering carpet of pretty velvety-lobed leaves above which shining yellow buttercups appear in May. These vanish in summer, returning in autumn to make cover between herbaceous plants that have died down. Thrives in well-drained soil and sun. Height: 30-40cm.
R. montanus ‘Molten Gold’ AGM is a nice alpine plant that produces a mound of fresh, bright-green foliage in the spring at the same time as large golden flowers. Height: 7cm.
R. repens ‘Fore Pleno’ is a cultivar of the creeping buttercup with taller stems and double yellow flowers. It will cross with the single-flowering weed, so do not plant them close together or you could find yourself invaded.
Thank you to Floramedia, which supplied the images for this article from its photo library