(Editor's Note: This article was originally published on June 28, 2008. Your comments are welcome, but please be aware that authors of previously published articles may not be able to promptly respond to new questions or comments.)
There are some 120 species of Anemone worldwide. For many years, the genus Pulsatilla was also included within Anemone but the seed structure of Pulsatilla, with their long plumes, was quite distinct and hence, they were separated into their own genus. You can refer to my article ‘Pasqueflowers - the Flower of Easter' for more details on this genus.
In the garden, anemone fall into 3 main groups. The focus of Part 1 of this 3 part series will be the tuberous and thick-rhizomed species. Part 2 will deal with the fibrous-rooted species which are primarily spring or early-summer bloomers while part 3 will present the fall-blooming species and hybrids.
The tuberous-rhizomatous species are all native to Eurasia, with most found around the Mediterranean region. There are two subgroups; the spring-bloomers and the summer bloomers. In the wild, the spring-bloomers grow in either woodland settings or subalpine meadows. In the garden, provide them with well-drained, humus-rich soil that is reasonably moist through the winter and spring months. Summer drought does not provide any problems as the plants are dormant during that season. The summer-bloomers naturally grow in rocky meadows and in the garden, prefer hot-summer regions and light sandy soils. They need to bake in late summer to keep them happy.
One of the most popular spring-blooming anemone is A. blanda or windflower (zone 3-9). The tubers of this species are planted in the fall about 5-8 cm deep and will bloom early the following spring. It is difficult to know which side is up and which down, but if you soak the tubers overnight, the smooth side vs. the rough side will be more noticeable. The smooth side is planted down. In spring, short-stalked, fern-like leaves emerge along with daisy-like flowers, usually several per tuber. The flowers may be blue (‘Blue Star', ‘Atrocaerulea'), pink (‘Charmer, ‘Radar') or white (‘Bridesmaid', ‘White Splendor'). They will increase with time and will often self-seed. Personally, this is my favourite anemone. Plants go dormant by late spring-early summer and the old leaves seem to disappear overnight so you are not left with ugly, dying leaves for an extended time. A look-alike, less-hardy species (zone 6-9) is A. apennina. These species will grow in sun or part-shade.
Some of the many colour forms of A. blanda
Also popular is A. nemorosa or wood anemone, a woodland species found throughout much of Europe. This species will reach 30 cm and spreads quickly by thick rhizomes, forming large colonies. They bloom in mid-late spring. The wild colour form is white but there are several named selections including ‘Allenii' (lavender-blue), ‘Robinsoniana' (pinkish-lavender), ‘Royal Blue' (blue) and ‘Vestal' (double white). Anemone altaica, a closely related species from Siberia, has white tepals (petal-like sepals) with violet veins. These prefer dappled sun. In western North America there is a similar species called A. quinquefolia which is rather rare in cultivation.
Some of the various forms of A. nemoralis ('Allenii', 'Robinsoniana', 'Royal Blue', wild form and 'Vestal) along with the American counterpart, A. quinquefolia
From the eastern USA is A. caroliniana, a species which should be more widely grown. It is a dainty plant with small but very attractive multi-tepaled flowers that are purple, lilac or white. A choice plant for the spring woodland garden.
The summer-blooming species in this group include A. coronaria, A. pavonina, A. hortensis and A. X fulgens. These are collectively known as the Grecian or poppy windflowers. By far the most popular of these is A. coronaria, available as hard, lumpy rhizomes in both spring (northern areas) and fall (southern areas). This group is only hardy in zones 8-9, possibly zone 7 if heavily mulched. In northern areas, they are often planted in spring, bloom in summer, then discarded or overwintered indoors. In mild regions they are better planted in fall and will bloom in late spring, then left to go dormant for the rest of the summer. This group makes admirable pot-plants. Their flowers are quite large and showy on plants around 30 cm. They come in white, pink, red or blue shades on single (De Caen group) or semi-double (St. Brigid group) flowers. Alternatively, you can purchase these by specific cultivar names. Grow these in full sun.
Examples of A. coronaria from the De Caen group
Examples of A. coronaria from the St. Brigid group
Anemone pavonina is similar to A. coronaria but the flowers are a little smaller
Stay tuned for part 2, the fibrous-rooted Anemone, which encompass quite a number of species, native to woodlands, prairie grasslands, alpine meadows or the high Arctic tundra.
I have many people to thank for photo use in this article: gregr18 for A. quinquefolia: LawrenceM for the two pictures of A. pavonina: Kell, kniphofia, LANCE92646, langbr, naturepatch and poppysue for the various pictures of the De Caen and St. Brigid anemone.