Anemone corms, often referred to as windflowers, are a rewarding choice for adding delicate color to the garden, particularly the popular spring-blooming Anemone blanda and the larger, poppy-like Anemone coronaria. These flowers grow from irregular, dry corms that look unlike typical bulbs, yet they produce vibrant, daisy-shaped blooms. Successful planting depends on understanding the specific needs of these corms.
Preparing the Corms and Determining Timing
The timing of planting depends on your local climate and the desired flowering season. Gardeners in mild-winter regions (USDA Hardiness Zones 7 and warmer) can plant corms in the autumn to encourage blooms early the following spring. This fall planting allows the corms to establish a strong root system during the cool, moist winter months. In colder areas (Zone 6 and below), planting is better deferred until late winter or early spring for late-spring or early-summer flowers, as harsh freezes can damage corms in the ground.
A pre-planting soak is necessary to rehydrate the dormant corms and initiate the germination process. Anemone corms are sold in a desiccated, hard state and will rot if planted dry in cold, wet soil before they can absorb water. Place the corms in a bowl of room-temperature water for approximately four to six hours until they visibly plump up, often doubling in size. Over-soaking is a risk, as it can cause the corms to rot.
Selecting the Ideal Site and Preparing the Soil
For Anemone coronaria, full sun exposure is preferred to maximize bloom production and stem strength. However, in climates with intensely hot summer afternoons, partial shade will help prolong the flowering period and prevent heat stress. Anemone blanda varieties are more tolerant of shade and thrive in areas with dappled sunlight, such as under deciduous trees.
The most important soil characteristic for anemone corms is excellent drainage; these plants will quickly succumb to rot if left in soggy conditions. When preparing the bed, amend heavy clay soils by incorporating generous amounts of organic matter, such as compost, leaf mold, or coarse horticultural grit. This improves the soil structure by creating air pockets that allow excess water to drain away freely. A soil pH that is slightly acidic to neutral is ideal for anemones.
Step-by-Step Planting Guide
Once the corms have been properly soaked and the planting site is ready, dig individual planting holes or a trench approximately one to two inches deep. The corms should be spaced about four to six inches apart to allow for adequate air circulation and growth. Closer spacing can be used for a denser display, but this increases the risk of fungal issues in humid conditions.
Identifying the correct orientation can be tricky, as anemone corms are irregularly shaped. If a distinct pointed end is present, that side should face downward, as it is typically where the roots emerge. If the corm is flat or highly irregular, it can simply be planted on its side, since the growing tip will naturally orient itself toward the soil surface as it sprouts.
After placing the corms, gently backfill the holes with the prepared soil, taking care not to disturb the newly planted corms. Lightly firm the soil surface with your hands to remove any large air pockets. The area should then be thoroughly watered one time to settle the soil around the corms.
Initial Care and Seasonal Maintenance
Following planting, the soil should be kept lightly moist but not saturated. Overwatering is the biggest threat to newly planted anemones, so allow the top layer of soil to dry slightly before watering again. Once new growth is visible above the soil, you can apply a balanced, slow-release granular fertilizer or a liquid feed to support flowering.
For long-term care, the overwintering strategy depends on the specific variety and the local climate. Hardy varieties like A. blanda are reliable perennials in USDA Zones 4–8 and can be left in the ground to naturalize, returning each spring. In contrast, the less cold-tolerant A. coronaria is often treated as an annual in Zones 6 and below. If not treated as an annual, the corms must be carefully lifted after the foliage dies back in the summer. These lifted corms should be dried and stored in a cool, dry, frost-free location for replanting the following season.