Dalea purpurea

Dalea purpurea, also known as Petalostemon purpureus or Purple prairie clover in its native land, is a very robust perennial plant that blooms in the summer in the great plains of the United States. Little planted in European gardens, this relative of alfalfa forms a vigorous bushy clump, equipped with remarkable adaptability and a very lovely summer flowering in pink-violet, very rich in nectar, which somewhat evokes the spikes of certain lavenders. It is a very hardy botanical species that enriches the soil and adapts well to both occasionally waterlogged and dry situations in summer. Its main enemy is shade.

Dalea purpurea (synonym Petalostemon purpureus) belongs to the Fabaceae family. In nature, it is found spontaneously in a large part of North America (except the West Coast of the USA), growing in various very sunny environments, from the floodplains of rivers to sandy hills in Nebraska, through the great meadows and forest clearings, among tall grasses, without any problem, perfectly tolerating frost and dry summers. It is a deciduous plant, devoid of foliage in winter.

The plant forms a bushy clump composed of semi-woody and branched stems, with a rather sprawling habit, reaching about 75cm (30in) in height and 60cm (24in) in diameter at minimum. Flowering takes place from June to August, in the form of numerous and peculiar conical spikes covered with tiny nectar-rich flowers. The colour, a bright pink-violet, is enhanced by golden stamens. The flowers generally open from the bottom to the top of the spike. The foliage, which disappears in winter, is composed of small, thick leaves, divided into three to 7 very narrow leaflets, about 3-4cm (1-2in) long. This plant develops from a particular root system, which dives very deeply (up to 2m (7ft)) into the soil to extract and transform nutrients thanks to the presence of symbiotic bacteria lodged in small nodules. Like all Fabaceae, this Dalea contributes to enriching the soil in which it grows.

Dalea are close relatives of Baptisia, sainfoin, and lupins, plants considered as green manure and soil fixers, even degraded ones. Not demanding in terms of soil and moisture, they are, however, completely intolerant to shade. Dalea purpurea will find its place in a romantic garden, a dry garden, in natural and countryside flower beds. It is also useful for decorating a degraded plot of land, which often surrounds a recently built house. It looks superb when combined with landscape roses, blue or white lavenders, Baptisias, or Allium bulgaricum. It also pairs perfectly with Amorpha canescens, Symphyotrichum sericeum (Silky Aster), or tall American grasses like Schizachyrium, Andropogon gerardii, and Panicum virgatum, which are equally spectacular and easy to grow.

Dalea purpurea is a medicinal and utility plant used for greening sterile soils and erosion prevention. Its foliage is good fodder for livestock. It was once used to prepare a tea, and its roots were also consumed, while its branches were used as brooms.