Vernonia arkansana - Ironweed

Vernonia arkansana is a large and beautiful wild vernonia native to the north and central United States, a robust cousin of asters with brightly coloured pink-violet flowers in late summer when grown in the damp soils it prefers. This perennial with sturdy leafy stems is still not widely used, but it is a lovely relative of tall asters that endures harsh winters and tolerates all types of moist soil. Plant it in a natural garden, it at the back of a border or near water features. It will look stunning with inulas, aconites, and silver candles.

Vernonia arkansana belongs to the Asteraceae family. It is a majestic plant found in Illinois, Kansas, southern Arkansas, Oklahoma, and the state of Missouri. It can be found along streams, on the edges of swamps, in meadows, and wet thickets, where it can reach up to 2m (7ft) high. In gardens, it is a herbaceous plant anchored by a strong perennial crown that generally reaches 1.50m (5ft) high and spreads 50cm (20in) across. The size of the plant depends on the soil's fertility and moisture content. Cutting back the stems in late spring helps reduce their height. It grows quickly, but it takes two years to establish itself. It forms a clump of tall and robust, straight, hairy, unbranched stems, bearing long, alternate, simple, narrow, pointed, smooth leaves that are medium green-blue. It Flowers from August to September-October depending on the climate. At the tips of the stems, inflorescences resembling small, fluffy, pink-violet pompoms appear grouped in terminal clusters or corymbs. The flowers all open at the same time, attracting a large number of butterflies for a magnificent spectacle. After pollination, rust-coloured seeds form. The vegetation is deciduous, emerging from the ground each spring and dying in autumn.

Very easy to grow in clayey and always slightly moist soils, this superb Vernonia arkansana pairs well with lots of plants and creates magnificent autumn compositions. On the banks of a pond, it spreads rapidly and combines with similar-looking eupatoriums, Lythrum salicaria, Filipendula rubra 'Venusta', Euphorbia palustris. In a wilder style, at the back of a border, this imposing perennial forms a very successful combination with Rudbeckia maxima, tall asters, and tall grasses such as Miscanthus 'Malepartus', Panicum, Stipa...