Potentilla is a small shrub that blooms through summer, the five buttercup-yellow petals of each blossom opening wide as if to smile back at the sun. After an initial flush of bloom, the quantity tapers off. But even a few of these 2-inch blooms, set above the dainty foliage, are enough to enliven the plants, which stand 2 feet high.
Give potentilla abundant sunlight and it will be happy. It tolerates heat well and is undaunted by winter cold. It will also grow in a range of soils: acidic or alkaline, wet or dry.
The plant looks best in summer. In winter a low hedge of potentillas looks like a roll of tumbleweed. The tangle of brown stems is somewhat attractive in winter, poking up through and catching bits of snow; the look is definitely preferable to bare soil. The bushes are scraggly but not overly so because of their small size and tight growth habit.
Eventually, however, potentillas get ragged enough to require some pruning to doff very old wood and stimulate tidier new growth. Prune the plant in late winter, either lopping everything to the ground every few years or selectively cutting some of the oldest stems every year. Whole plants pruned to the ground recover quickly, even blooming again the same year they are cut.
There are many wonderful hybrids of potentilla, with colors ranging from white through yellow to red. The variety Abbotswood has white flowers and blue-green leaves, while flowers of Moonlight and Primrose Beauty are pale yellow. Moving toward red are the pure yellow flowers of Goldfinger, the yellow-red of Tangerine and the vermilion of Red Ace.
Aside from these cultivated potentillas, there also are numerous wild ones. The plant's name is derived from the Latin word meaning "potent" and refers to medicinal uses of wild potentillas. It also is known as cinquefoil--five-leafed.
In old herbals, potentilla was recommended as an astringent to bring down fevers, as a sedative for hysteria epilepsy and as a gargle for sore throats or swollen tonsils.
Potentilla was a favorite herb of witches and sorcerers, perhaps because of its hand-shaped leaves. It is odd that potentilla should have such sinister associations, especially because the 17th century herbalist Culpeper wrote that potentilla is ruled by the planet Jupiter and is therefore considered soothing, cheering, benevolent and otherwise jovial.