New foliage of Ageratina altissima ChocolateThis interesting herbaceous perennial from North America (where it is known colloquially as white snakeroot) was once called Eupatorium rugosum 'Chocolate' (which is what I bought it as years ago) but its name has changed. An unusual member of the Asteraceae (daisy) family, it forms a clump of nettle-like leaves that are beautifully flushed with purplish-brown when they emerge in early spring. The plant grows to about 1 m tall and bears clusters of small fluffy white flowers in summer, rather like Ageratum, which are attractive to butterflies and bees.
Flowers of Ageratina altissima ChocolateThe leaves become green as summer progresses but the purplish-brown tones are present when the flowers first appear, and dark stems add to the contrast. It does need some support as it has a tendency to flop - cradle stakes are ideal. It becomes rather tatty by late summer and it is something a relief to cut it down to the ground in autumn. It likes a little lime in the soil and prefers a part-shaded position. If it is grown in full sun, the leaves may be scorched and new growth may be damaged - and the plant may wilt on hot days. It likes reasonable moisture. Clumps may be easily divided in winter. I have never had any self-seedlings appear, but this has been noted by gardeners in USA as a negative aspect of this plant. Note also that all parts of plant are poisonous if ingested.