Rue-anemone (Thalictrum thalictroides) flourishes best under deciduous trees. It prefers direct sunlight but will tolerate partial shade. It’s sometimes called “Windflower” because the flowers effortlessly move around in even the slightest breeze.
I. Appearance and Characteristics
Thalictrum thalictroides (syn. Anemonella thalictroides), the rue-anemone or windflower, is a herbaceous perennial plant native to woodland in eastern North America. It has white or pink flowers surrounded by a whorl of leaflets, and it blooms in spring.
Thalictrum thalictroides is a hairless plant growing from a cluster of tuberous roots, with upright stems 10 to 30 cm (4 to 12 in) tall that end with flowers. The basal leaves have petioles (leaf stalks) 10–30 cm (4–12 in) long and leaf blades that are twice ternately compound. The leaflets are widely rounded in shape and the ends are three lobed.
It flowers in spring, with flowers borne singly or in umbel-like inflorescences with 3 to 6 flowers. The flowers have short stems that hold the fully opened flowers above the foliage. The involucral bracts have three leaflets like the leaves. The showy rounded flowers have 4-15 carpels surrounded by many yellow stamens in the middle, and a cup of 5 to 10 white to pinkish-lilac petal-like sepals. The sepals are about 5 to 18 mm (3⁄16 to 11⁄16 in) long and the filaments 3–4 mm (1⁄8–3⁄16 in) long.
In late spring, 3 to 4.5 mm (1⁄8 to 3⁄16 in) long, ovoid to fusiform shaped fruits called achenes are released. The green achenes have 8 to 10 prominent veins and become dark brown when ripe.
The Latin specific epithet thalictroides is in reference to the plant’s leaves that look similar to meadow rue.
Similar species
The rue-anemone is often confused with the similar species, the false rue-anemone (Enemion biternatum). Both plants have white flowers that appear in early spring and grow in wooded areas. However, the false rue-anemone is more likely to be found in moist bottomlands and can form large colonies, while the rue-anemone grows singly on wooded slopes. Sometimes rue-anemone sepals are pale to dark pink, whereas false rue-anemone sepals are always white. The false rue-anemone holds its flowers in leaf axils, most often singly. In contrast, the flowers of a rue-anemone appear in a cluster above a whorl of leaf-like bracts, most often in groups of three to six. While false rue-anemones always have five sepals, rue-anemones can have five to ten sepals. False rue-anemones have a small cluster of no more than six green carpels in the center of the flower, while rue-anemones sometimes have as many as fifteen. False rue-anemones usually have deep clefts in their leaves, while rue-anemones do not.
II. How to Grow and Care
Sunlight
Given rue anemone is native to woodland areas of eastern North America, it shouldn’t be a surprise that it prefers a shady spot. During the spring, it’ll thrive in partial shade, but when it goes dormant, full shade isn’t usually a problem for this plant.
This makes the species a great choice for planting under deciduous tree canopies. In the spring, they’ll receive the dappled light they prefer to grow in. When they go dormant during the summer, they’ll still survive when the tree canopy is at its thickest and doesn’t offer much light to the ground below.
Temperature and Humidity
Rue anemones, despite their delicate-looking appearance, are surprisingly hardy in their established range, zones 4a to 8a. They can tolerate hard spring frosts and still produce blooms.
This plant isn’t suited to be grown in areas that experience overly hot, sunny, and humid conditions.
Watering
Because rue anemones can cope without too much moisture, this species won’t need a lot of additional watering, especially if the area has a covering of mulch. Rue anemone is fairly drought tolerant, but keeping them moderately moist will ensure the longest bloom period in spring. If the plant is too wet, the tuber roots can begin to rot, and overly dry conditions can result in an earlier than normal dormancy.
Its drought tolerance is a benefit if the rue anemone is planted under large, well-established trees, which absorb a lot of the available moisture into their sprawling root systems.
Soil
Rue anemone prefers loose, humus-rich loamy, or sandy soils, but it can cope with a variety of soil types. It does need to be well-drained, though, as these plants don’t do well in standing water or overly moist conditions. Ideally, the soil should be nearly neutral in pH, but slightly acidic or slightly alkaline soils are usually not a problem.
If they’re planted under trees, the falling leaves and other rotting organic material will be of benefit. A thin layer of mulch can help to retain moisture in dry soils and will protect against late spring frosts.
Fertilizing
A native wildflower, rue anemone requires no supplemental feeding if grown in suitable circumstances—well-draining humus soil that is somewhat sandy. At most, a layer of compost applied as a mulch over the root zone in fall is sufficient.
Propagation
The rue anemone has clusters of small tuberous roots, which are easily divided to propagate new plants. It’s best to wear gloves when handling this plant to avoid skin irritation. Rue anemone can be propagated through root division. Here’s how:
- In early spring as the plants are just coming out of dormancy, carefully dig up the entire root clump with a trowel.
- Use the trowel or a garden knife to slice down through the root clump, dividing it into as many as eight pieces. There is no need to make sure each section has an eye—the plant will regrow from even the smallest of root pieces.
- Immediately replant the pieces so the roots are just buried, in moderately moist, humus soil that is well draining. Water well after planting, then weekly until robust new growth is evident.
How to Grow from Seed
Although it’s easier to grow new plants from root division, it’s possible to grow rue anemone from seeds collected in early summer. They’ll need to fully dry out before sowing and can benefit from a cold stratification period. Either plant them in the fall or keep them moist in a refrigerator for a few months before planting. You shouldn’t expect any flowering in the first season following germination—it can take as much as three years for them to reach flowering maturity.
Volunteer plants that arise from self-seeding can also be dug up and transplanted to new locations. Do this in the spring as the volunteers are just emerging.
Overwintering
This hardy wildflower needs no winter protection against cold if planted in its established hardiness range (zones 4a to 8a). Late fall can be a good time to apply a layer of compost over the plants to provide nutrients for the following spring.
How to Get to Bloom
Rue anemone generally produces one to six flower stalks per plant, each stalk with one flower, during the spring. If they are not flowering in this way, there are several possible reasons:
- Plant is immature. These are slow-growing plants that can take several years before they flower. If you’ve just divided and replanted them, don’t be surprised if they don’t flower for a year or two.
- Not enough moisture. Though these plants are drought-tolerant, the flowering display is often reduced if the spring is uncharacteristically dry. Supplemental watering during early dry periods may ensure better flowering.
- Too much sun. These are shade-loving plants. Too much sun often inhibits flowering.
Pests and Diseases
Common Pests & Plant Diseases
This wildflower is often entirely trouble-free, but in moist conditions, it is sometimes susceptible to fungal diseases, such as powdery mildew, rust, and leaf smut. These diseases rarely kill the plant but can be controlled with fungicide sprays if desired. Rue anemone can also be a favorite food of slugs, which can be controlled by hand-picking or baiting.
These plants don’t like extremely damp conditions, which may cause root rot.
Common Problems
The most common complaint is not a problem, but rather the plant’s natural behavior: It dies back as spring gives way to summer, leaving empty spots in the woodland garden. This is best remedied by planting rue anemone among other shade-loving perennials that fill out later in the season. such as hosta, lungwort, or Jacob’s ladder.
