Despite being known as Japanese anemones, three main species - A. hupehensis, A. vitifolium and A. tomentosa - actually come from China. These were erroneously called Japanese anemones after one particular form was first recorded near Nagasaki in 1695. By the time the first plants reached the west in 1844, they were already known as A. japonica. Most modern varieties are descended from A. x hybrida.
Recommended varieties:
* A. hupehensis 'Hadspen Abundance': a fairly recent variety in deep lilac-purple with five rounded petals. The Royal Horticultural Society has given it its Award of Garden Merit (AGM).
* A. hupehensis 'Bressingham Glow' and 'Prinz Heinrich': these semi-double varieties of A. hupehensis var. japonica have dark purple flowers and typically narrow petals totalling 20 or more. In the late 1800s there was a double white called 'Couronne Virginale', but it was lost without trace, although there have been claims that a French nursery has found a double. 'Prinz Heinrich' has been given the Royal Horticultural Society's AGM.
* A. x hybrida 'Honorine Jobert': immensely popular, it's a pure white that occurred as a chance mutation on A. x hybrida in the garden of M. Jobert, in Verdun, France, in 1858. Its flower stems can reach over 1.8m (6ft) in fertile soil, and the large, simple flowers with golden stamens have a graceful quality few other blooms possess. Has been awarded the AGM.
* A. x hybrida 'Konigin Charlotte': also known as 'Queen Charlotte', this popular variety was bred in Germany in 1898. It has large, semi-double pink flowers with up to 15 broad petals. Has been awarded the AGM.
* A. x hybrida 'Rosenschale': a promising new vigorous variety that produces large, rich pink flowers.
* A. x hybrida 'Margarete': the nearest that can be found to a double, this rarely sold anemone has up to 30 narrow, pale purplish-pink petals giving a slightly shaggy appearance. Was previously named 'Lady Gilmour'.
* A. x hybrida 'Whirlwind': a semi-double form in white, often with an unusual ruff of green and distorted outer petals.
* A. tomentosa: not as popular as it was, this traditional variety has copious pale pink blooms and attractive foliage that is greyish-white underneath, especially when young. Is also the first to flower, often in July, well before the hybrids.
* A. vitifolium: a charming species with white flowers above its vine-like leaves. Is rarely seen in British gardens, as it needs a particularly warm, sheltered position to thrive. BBC - Gardening