Grasses that were introduced into Japan around 250 years ago and now naturalized here – called Solidago, also known as Goldenrod, are in bloom everywhere right now.
About 80 perennial species make up the genus Solidago, most being found in the meadows and pastures, along roads, ditches and waste areas in North America, now naturalized also in Japan, and a few from Europe that were introduced some 250 years ago.
Many species are difficult to distinguish. Probably due to their bright, golden yellow flower heads blooming in late summer, the goldenrod is often unfairly blamed for causing hay fever in humans. The pollen causing these allergy problems is mainly produced by Ragweed (Ambrosia sp.), blooming at the same time as the goldenrods. Actually, goldenrod pollen is too heavy and sticky to be blown far from the flowers. Furthermore, goldenrods are pollinated mainly by insects.
Goldenrods are easily recognized by their golden inflorescence with hundreds of small capitula, but some are spike-like and other have auxiliary racemes.
They have slender stems, usually hairless but S. canadensis shows hairs on the upper stem. They can grow to a length between 60 cm and 1.5 m.
Their alternate leaves are linear to lanceolate. Their margins are usually finely to sharply serrated.
Propagation is by wind-disseminated seed or by underground rhizomes. They form patches that are actually vegetative clones of a single plant.
Posted on: Tuesday October 17, 2006