Aralia cordata (Japanese Spikenard)
Aralia cordata, commonly known as Japanese Spikenard, is a large, bold perennial native to East Asia. This striking plant features large, compound leaves that can grow up to 3 feet long, creating a lush, tropical appearance. In late summer, it produces clusters of tiny white to greenish flowers that attract pollinators, followed by small purple-black berries that birds love. Its impressive size and unique appearance make it a great focal point in shaded or woodland gardens.
Light Requirements:
Japanese Spikenard thrives in partial to full shade, making it ideal for woodland gardens or shaded borders. It can tolerate some morning sun but does best in filtered or dappled light, especially in hotter regions, where too much direct sunlight can scorch its large leaves.
Soil:
This plant prefers moist, well-draining soil rich in organic matter. Aralia cordata thrives in loamy or slightly sandy soil, but the key is ensuring that the soil retains moisture without becoming waterlogged. Adding compost or well-rotted organic material will improve both soil fertility and drainage.
Height/Spread:
Japanese Spikenard can grow up to 6 to 10 feet tall and spread 3 to 6 feet wide, depending on the growing conditions. Its towering height and broad, lush foliage create a dramatic presence in the garden.
Hardiness Zones:
Aralia cordata is hardy in USDA Zones 4-8. It can tolerate cold winters and will die back to the ground in the fall, returning with vigorous growth in the spring.
Winter Care:
In colder regions, Japanese Spikenard naturally dies back to the ground after the first frost. Once the foliage dies back, you can cut the plant down to the ground. Applying a layer of mulch around the base in late fall will help insulate the roots during the winter. The plant will re-emerge in spring with new shoots.
Watering:
Aralia cordata prefers consistently moist soil, so water regularly, especially during dry periods. The soil should be kept evenly moist, but be careful not to overwater, as the plant does not tolerate standing water. Mulching around the base of the plant helps retain moisture and keep the roots cool.
Fertilizing:
This plant benefits from rich soil, so adding compost or organic matter in the spring will promote healthy growth. A balanced, slow-release fertilizer applied in early spring can also help boost foliage and flower production. Avoid over-fertilizing, as it can lead to leggy growth.
Pruning:
Pruning for Japanese Spikenard is minimal. In early spring, you can remove any dead or damaged stems to encourage new growth. After flowering in late summer, you can cut back spent flower heads if desired, but leaving them will allow for the development of berries, which attract birds. In the fall, the entire plant can be cut back to the ground as it enters dormancy.
Propagation:
Aralia cordata can be propagated by division or seeds. Division is best done in early spring before new growth begins. Carefully dig up the plant and separate the rhizomes into smaller sections, ensuring each division has roots and at least one growth bud. Replant the divisions in well-prepared soil. Seeds can be sown in the fall, though they may take longer to germinate and grow.
Pests and Diseases:
Japanese Spikenard is relatively pest and disease-free. However, slugs and snails may occasionally feed on the foliage, especially in damp conditions. You can control these pests with organic slug deterrents. The plant is also fairly resistant to diseases, though ensuring good air circulation around the plant will prevent any potential fungal issues.
Summary:
Aralia cordata (Japanese Spikenard) is a striking, shade-loving perennial known for its large, tropical-looking leaves and late-summer clusters of small white flowers and berries. Thriving in partial to full shade and moist, well-draining soil, it grows 6 to 10 feet tall and 3 to 6 feet wide. Hardy in USDA Zones 4-8, this low-maintenance plant requires regular watering, minimal pruning, and occasional fertilization, making it an excellent choice for adding drama and texture to shaded gardens or woodland areas.