Syneilesis aconitifolia is a woodland perennial native to China, Japan, and Korea in the Asteraceae family. It is grown almost entirely for its foliage: each spring, new shoots emerge as silvery, cobweb-hairy, tightly folded forms that resemble collapsed parasols. Over several weeks these unfurl into deeply palmate, dark green leaves up to 18 inches across, holding strong textural presence through fall. Small off-white flower clusters appear on upright stems in midsummer on mature clumps.
The plant spreads slowly by short rhizomes and is rarely aggressive. It performs best under deciduous canopy with dappled light and consistent moisture without waterlogging. Amend planting sites with leaf mold or compost. The crown requires good drainage to avoid rot, but once established the plant tolerates periodic dry spells better than many shade perennials. In zones 4 and 5, mulching the crown with shredded leaves over winter improves survival. Division is the standard propagation method; seeds require cold stratification.
In traditional Chinese and Korean medicine, roots and aerial parts of Syneilesis have been used for rheumatic pain and swelling. The genus contains sesquiterpene lactones, compounds common across Asteraceae that have shown anti-inflammatory activity in laboratory studies.
Fungal leaf spot
Brown or purplish spots on the leaves, often ringed with a yellow halo, that spread and merge in warm, humid, or wet weather; heavily spotted leaves yellow and drop early.
Pick off spotted leaves and clear fallen debris to remove overwintering spores. Improve air circulation by thinning, and water at the base so foliage dries quickly. If it persists, apply a copper- or sulfur-based fungicide at the first sign.
Root rot
Plants wilt, yellow, and stunt even in moist soil; lower stems and roots turn brown, soft, and mushy and the plant may collapse. Most common in heavy, wet, or poorly drained ground.
Improve drainage and stop overwatering, and never plant too deep. Lift and destroy badly affected plants along with the soil around the roots. Grow in raised or free-draining beds to prevent it returning.
Powdery mildew
White or grey powdery coating on leaves — usually starting on older growth in humid conditions or when nights cool.
Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.