Spiraea douglasii

The Spiraea douglasii is a botanical species from North America that has adapted very well to our local conditions. This hardy and fast-growing bush forms large clumps up to 1.80 m (6ft) tall and more, and spreads in width over the years. Growing in neutral to acidic, moist to wet soils, it is the ideal easy plant for vegetating a bank or forming a wild hedge. It flowers throughout the summer, producing numerous long, fluffy spikes of deep and shiny pink that are highly visited by pollinating insects.

The Douglas Spirea belongs to the large and important family of Rosaceae, which blesses us with so many ornamental species (Roses obviously, but also Photinia, Cotoneaster, Amelanchier...). In France, there is only one native species of Spirea, the S. hypericifolia, or St. John's Wort-leaved Spirea, which is found in the wild around the Massif Central. Other species or varieties are also present, but they are human introductions for ornamental purposes that have escaped from garden enclosures.

This is particularly the case with the Douglas Spirea, which, originating from North America (over a vast territory, covering the entire west from Alaska to California), has naturalized in eastern France (Franche-Comté, Burgundy...) without being invasive, especially since there is some confusion in the precise identification of certain Spiraeas, a genus rich in over a hundred species (the Spiraea x billardii, a hybrid between the Douglas Spirea and S. salicifolia, is very morphologically similar to its parent...).
The growth of the Douglas Spirea is fast and its adult size will reach about 1.80 m (6ft), even 2 m (7ft) in all directions. Lateral growth occurs through suckers that grow on the periphery of the stump, from which many thin and erect branches emerge. In a garden scale, this bush can therefore become cumbersome if one wishes to keep it in a well-maintained bed... The habit of this spirea is upright, dense, and very bushy. The deciduous foliage consists of oblong, lanceolate, dentate leaflets, 6 to 10 cm (2 to 4in) long, of a medium green color. The summer flowering lasts approximately 2 months, between late June and September, in the form of pink, elongated panicle inflorescences at the ends of the branches. 10 to 12 cm (4 to 5in) long, they are composed of a multitude of small cup-shaped flowers of an intense pink, from which stamens emerge, responsible for the fluffy appearance of the inflorescence.
Extremely hardy (down to -25° or -30 °C), this Spirea does not like limestone, growing in neutral to acidic, moist or even wet soils. It is capable of colonizing a bank, growing in full sun or semi-shade. Very undemanding, it is a trouble-free plant.

This Spirea will be particularly appreciated in a flowering or free hedge, where it will bring diversity to the heart of summer. You can plant it with other plants of a natural appearance to create a slightly wild atmosphere. The Cotoneaster franchetii with its small evergreen leaves and flowering in May-June followed by decorative red berries, our European Spindle (Euonymus europaeus) with its rich autumn colors and pink and orange fruits, or a botanical rose like the Rosa glauca, with its bluish foliage and pretty pink flowers, will be good companions. It will also be particularly at ease on the edge of watercourses, with other plants with similar affinities such as Astilbes with their magnificent vibrant flowers, low to medium perennials that you can plant at the base of your Spirea.