Arisaema costatum
A striking and unusual woodland perennial, Arisaema costatum is a captivating cobra lily with bold foliage and dramatic, hooded flowers. Its deep green, wide pleated leaves create an elegant backdrop for the distinctive spathes, which emerge in early to midsummer. The flowers, typically dark purple to maroon with pale striping, have a gracefully curved spadix that adds to their exotic appeal. As summer fades, clusters of bright red berries appear, providing further interest well into autumn.
Sold currently as flowering size corm
Height & Spread: Grows to around 40-60cm in height with a spread of approximately 30cm.
Soil: Prefers moist, humus-rich, well-drained soil with good organic content.
Position: Thrives in partial to full shade; ideal for woodland gardens, shaded borders,
Flowering Time: midsummer
A striking and unusual woodland perennial, Arisaema costatum is a captivating cobra lily with bold foliage and dramatic, hooded flowers. Its deep green, wide pleated leaves create an elegant backdrop for the distinctive spathes, which emerge in early to midsummer. The flowers, typically dark purple to maroon with pale striping, have a gracefully curved spadix that adds to their exotic appeal. As summer fades, clusters of bright red berries appear, providing further interest well into autumn.
Sold currently as flowering size corm
Height & Spread: Grows to around 40-60cm in height with a spread of approximately 30cm.
Soil: Prefers moist, humus-rich, well-drained soil with good organic content.
Position: Thrives in partial to full shade; ideal for woodland gardens, shaded borders,
Flowering Time: midsummer
A striking and unusual woodland perennial, Arisaema costatum is a captivating cobra lily with bold foliage and dramatic, hooded flowers. Its deep green, wide pleated leaves create an elegant backdrop for the distinctive spathes, which emerge in early to midsummer. The flowers, typically dark purple to maroon with pale striping, have a gracefully curved spadix that adds to their exotic appeal. As summer fades, clusters of bright red berries appear, providing further interest well into autumn.
Sold currently as flowering size corm
Height & Spread: Grows to around 40-60cm in height with a spread of approximately 30cm.
Soil: Prefers moist, humus-rich, well-drained soil with good organic content.
Position: Thrives in partial to full shade; ideal for woodland gardens, shaded borders,
Flowering Time: midsummer
Arisaema are fascinating woodland perennials, but to thrive in Scotland’s climate, they require careful planting and winter protection. Here are some essential tips to ensure their successful establishment:
1. Planting Depth & Position
Arisaema tubers should be planted deeply, around 5 inches (12-15cm) below the soil level. This depth helps protect them from winter cold and excessive moisture. Choose a sheltered, partially shaded spot with dappled light, such as under deciduous trees or among ferns and hostas. Avoid areas prone to waterlogging.
2. Improving Drainage
Good drainage is essential to prevent tuber rot, especially in Scotland’s wetter conditions. When planting, add a layer of gravel or coarse grit at the base of the hole to improve drainage and prevent standing water around the tuber. Incorporate leaf mould or well-rotted compost into the soil to enhance structure while maintaining moisture balance.
3. Winter Protection
In colder regions, a thick winter mulch is highly recommended. Once the foliage dies back in autumn, cover the planting area with a layer of leaf litter, or bark mulch to insulate the tubers from deep frost. In particularly harsh winters, consider adding a horticultural fleece or an upturned pot over the crown for additional protection.
4. Watering & Care
Keep the soil evenly moist during the growing season, but avoid overwatering. Arisaema dislike sitting in water. Once dormant, reduce watering significantly, as excess winter moisture can lead to rot. Avoid disturbing the tubers—Arisaema tend to settle in over time and perform best when left undisturbed.
