Solidago canadensis

Solidago canadensis, or goldenrod, is an ideal species to brighten up large spaces and the backgrounds of flower beds, with golden plumes throughout the summer. But beware, this robust and hardy perennial can become invasive. Use it sparingly in the background of flower beds alongside blue flowers or to fill neglected slopes where it will attract pollinators all summer.

Solidago candensis, also known as Canadian goldenrod, is a large deciduous herbaceous perennial with rhizomes belonging to the Asteraceae family. It is native to North America but is now naturalised throughout Europe. It can be found in a variety of habitats, but never in shade. It is considered a pioneering plant, colonising areas disturbed by fires, for example, except in very dry areas or waterlogged soils.

This species grows between 50 cm (20in) and 1.50 m (5ft) high with no limit to its expansion due to its rhizome. It forms a dense, flexible clump of hairy and leafy stems. Flowering occurs from July to September, depending on the climate, in the form of pure yellow inflorescences that seem to emerge from the foliage. These are feathery, light panicles of tiny flower heads in branched and feathery spikes. They appear at the end of robust and hairy stems carrying opposite, elongated, rough, light green leaves with slightly toothed edges. This goldenrod disappears in late autumn to reappear in spring.

These perennial plants are highly appreciated for their late flowering which attracts pollinators. There is a risk of them becoming invasive. They are robust plants that only dislike excessive heat and drought, which can cause powdery mildew on the foliage. Solidago canadensis can be planted individually or in groups of three, close to  blue asters (Aster lævis Calliope) or mauve asters (Aster turbinellus), cosmos, Crambe cordifolia, and veronicas (Veronica incana, Veronica longifolia), for example. Its flowers hold up well in bouquets, and they can also be dried before fully blooming to be included in dried arrangements.