A plant with a public image issue, Persicaria amplexicaulis ‘Alba’ (mountain fleece). You may be familiar with this Polygonaceae by its older botanical name, Polygonum amplexicaule ‘Alba’. Polygonums, often called knotweeds, have a reputation as aggressive and weedy exotic, even invasive, plants. Persicaria amplexicaulis ‘Alba’ is a well-behaved garden plant with no aggressive or invasive tendencies.
Mountain fleece is native to China, the Himalyas, and Pakistan where it is often found along stream-sides and wet meadows. In the garden setting, P. amplexicaulis grows best in USDA Zones 4-7 where it often reaches to 1.2 m (4 ft.) tall with a 1.2 m (4 ft.) spread. Plants will grow in full-sun to part-shade; however, if grown in full-sun plants must be watered often to prevent yellowing of leaves. When grown in part-shade with ample soil moisture, plants remain strongly upright and will form large, dense bushy colonies.
Persicaria amplexicaulis ‘Alba’ flowers from June-October/November producing terminal spikes densely packed with small, soft white flowers. The upright stems present ovate, stem clasping leaves with a matte green color. Since plants often form dense colonies, best to consider using P. amplexicaulis ‘Alba’ as a mass planting or in a large sweep in the garden. At Lurie Garden, ‘Alba’ is planted in combination with P. amplexicaulis ‘Firedance’ which provides great contrast in flower color.
|Botanical Name||Persicaria amplexicaulis ‘Alba’|
|Common Name||knotweed ‘Alba’|
|USDA Zone||4 to 7|
|Light Requirement||Full Sun to Part Shade|
|Season(s) of interest||Summer, Fall|
|Height and Spread||
1.5-3 ft x 1.5-3ft (45-90cm x 45-90cm)
P. amplexicaulis native to the Himalayas
|Location in Lurie Garden||Southeast Dark Plate|