Anemones, often called Windflowers, are a diverse group of garden plants cherished for their delicate, cup-shaped blooms and their ability to naturalize in the landscape. They generally multiply over time, forming attractive clumps and drifts in garden beds. The speed and method of this increase depend entirely on the specific species planted, as Anemones utilize several different underground structures to propagate themselves. The multiplication process can range from a slow, steady increase to a quick, aggressive spread.
The Process of Underground Multiplication
The structure commonly referred to as an Anemone “bulb” is usually not a true bulb, but rather a corm or a tuber. True bulbs, such as those of tulips, are made up of fleshy, layered scales. Anemone corms and tubers are solid, swollen portions of the stem or root used to store nutrients and water during dormancy. This underground storage organ is the reproductive engine for many spring-blooming varieties, like the Grecian Windflower (Anemone blanda).
A corm multiplies by creating new, smaller corms called cormels or offsets. As the original corm expends its stored energy to produce foliage and flowers, new offsets form at the base of the stem, often just above the spent parent structure. This leads to a dense cluster of new plants, which can be separated to create fresh plantings elsewhere.
Some other Anemone species, particularly the taller, fall-blooming types, do not rely on corms at all, but instead spread using rhizomes. A rhizome is a horizontal, underground stem that grows sideways, sending out roots from the underside and shoots upward from nodes along its length. This method allows the plant to send up new growth several inches away from the original clump, resulting in a creeping, expansive spread across the garden bed.
Varying Spread Rates Among Anemone Species
Spring-flowering types, such as Anemone coronaria (Poppy Anemone) and Anemone blanda, grow from corms or tubers and multiply at a slow to moderate rate. These types gradually form tighter clumps over several seasons as the parent corms produce offsets. Their spread is generally self-limiting, resulting in a dense, localized patch of flowers.
In contrast, other Anemone species use a rhizomatous root system, allowing for rapid and aggressive colonization of space. Japanese Anemones (Anemone x hybrida), which bloom in the late summer and fall, are a prime example. These plants use spreading underground runners to send up new shoots, often resulting in the plant appearing further from its original planting site.
Species like the Canada Anemone (Anemone canadensis) and the Wood Anemone (Anemone nemorosa) also use rhizomes to spread, establishing themselves as effective groundcover. In ideal conditions, the growth rate of these rhizomatous types can be expansive, potentially allowing them to overtake smaller, neighboring plants. This difference in multiplication habit means gardeners should choose their Anemone variety based on whether they desire a contained clump or an extensive groundcover.
Utilizing Anemone Division for Propagation
Gardeners can actively manage and accelerate the multiplication process by manually dividing the underground structures during the plant’s dormant period. For corm-producing species, this is usually done in the fall after the foliage has died back. The process involves carefully lifting the entire clump and gently breaking off the smaller, newly formed cormels from the larger, parent corm.
These newly separated offsets can be replanted immediately in a new location or stored in a cool, dry place over winter for planting the following spring. Before replanting, soaking the shriveled corms in lukewarm water for a few hours is recommended to rehydrate them and encourage quicker sprouting.
Managing rhizomatous Anemones, like the Japanese varieties, also involves division, but the technique differs due to their spreading root structure. The best time to divide these plants is in the early spring, just as new growth is emerging, or in the autumn. The entire root ball should be dug up, and a sharp tool used to cut the root mass into sections, ensuring each new division has a portion of the crown and a healthy segment of the rhizome. For aggressive spreaders, this division creates new plants while controlling their colonization.