Solidago altissima

Several North American species of goldenrod family have been introduced to Finland as ornamental plants. They are perennial, rhizomatous, tall grasses that often form extensive stands. The most common of them is the Canadian goldenrod (Solidago canadensis), also known as common goldenrod, which can grow up to 1.5 m tall. Less common are a taller Canada goldenrod (S. altissima) and even more bulky giant goldenrod (S. gigantea). In addition, grass-leaved goldenrod (Euthamia graminifolia) and cross-bred varieties of goldenrod for horticultural use (S. Canadensis -Group) have been found in Finland.

North American goldenrods are perennial, large grasses which often forms extensive growths; because of the large rhizomes the growths are very long lived. In addition to home yards and gardens, they grow in a wide variety of habitats modified by humans, for example on wasteland, riverbanks, roadsides and railway banks, and abandoned farmland.

Goldenrods reproduce both from seed and vegetatively from rhizome bodies. They produce a large number of seeds: a single shoot can produce more than 10,000 seeds. Hairy seeds (actually achene) spread along with the wind over long distances. The rigid stems of goldenrods persist a long time in winter, which allows the seeds to spread on the snowget more unhindered than in summer. Harmful goldenrods can also easily spread from place to place along with fragments of rhizome, or plant debris and soil which contains parts of rhizomes.