Buttercup

Ranaculus is the largest genus in the family, with well over 600 species found throughout the globe.  You’d think that with all that choice, they would be much more common garden plants than they actually are but that’s not really the case. Many of them are wildflowers, and even more of them are weeds. Most of them are simply not good garden plants. There are, however, exceptions to this.

All species of buttercup are poisonous, especially to livestock. One of the first signs of poisoning is sudden blistering around the mouth and lips, followed by bloody diarrhea. In serious cases, death follows shortly after ingestion.

The creeping buttercup (Ranunculus repens) is an aggressive perennial for wet areas so it makes an effective groundcover. It has shining yellow flowers in late spring and is great for cutting. The double flowered form, R. repens var. pleniflorus, is far superior and the blossoms look like tiny golden roses. If you have a spot where it can spread and flower in mass, it is a thing of great beauty. There is also a cultivar called ‘Buttered Popcorn’ that has poor flowers but golden marbled foliage that is quite stunning.

The Persian buttercup (R. asiaticus) comes from the eastern Mediterranean and has gorgeous flowers that are usually red through orange or pink, but can also be yellow or white. It is rare and protected in many places where it grows, but there are double flowered forms that are extremely popular as bedding plants and cut flowers. The blossoms are so double as to be almost surreal - looking more like cushions or fancy ribbons than actual flowers. They grow from delicate, rather small, octopus-shaped tubers. They are resentful of disturbance and need consistently moist soil. Persian buttercups require cool temperatures to perform well and flower over several weeks. They are often available as small, potted plants and should be discarded when flowering is finished as they go dormant soon after they conclude blooming. They aren’t especially hardy so they are usually grown as annuals.

Ranunculus ficaria is a tuberous species that comes from western parts of Europe including Great Britain. It is generally considered a weed and it spreads very rapidly, producing golden flowers in spring in moist areas and then promptly going dormant when the heat of summer comes. One cultivar, introduced by the late British gardener Christopher Lloyd in the 1970’s, is worth having. ‘Brazen Hussy’ has the familiar golden flowers, but gorgeous bronzy-purple to chocolate colored foliage that make the blooms especially showy. It is a useful plant for a moist area, and will grow where few other plants will.

One final species that we can't grow here but bears mentioning is the Mt. Cook lily (Ranunculus lyallii), endemic to New Zealand and famous as the largest buttercup in the world. It grows from stout rhizomes at high altitudes and requires a sunny spot, sharp drainage, and cool temperatures. It is notoriously difficult to cultivate and germinating the seeds is a significant challenge. When in bloom, it produces magnificent, 5” white blossoms and where conditions suit, it often grows in mass. It flowers from late spring through early summer and is one of the major drawing points for tourists visiting Mt. Cook National Park.