People usually laugh when I tell them what a great plant goldenrod is. It has a bad reputation as a weed and as a plant that causes allergies. Some species of goldenrod can get a little weedy in good soil. As for goldenrod causing allergies, it's not likely because goldenrod's pollen is rather large and could not possibly float in the air. The more likely cause of the allergies is ragweed, which flowers at the same time. It has green flowers and is not as noticeable as goldenrod.
Showy goldenrod is a wonderful plant, it generally stays where you put it, grows in clumps and will spread by seed. The flowers are a vibrant yellow and attract a wide variety of pollinators, bumble bees, honey bees, butterflies, and moths. Birds such as the Eastern Goldfinch will eat the seed and moth caterpillars use the plant for food.
Showy goldenrod leaves are about 6 inches long and 1.5 inches wide, tapering at the end. They are bright green and the stem is green or reddish. The plant grows 2 to 3 feet tall in Western New York.
So what makes showy goldenrod a great plant when you are designing a garden? It has a long bloom period, usually beginning in August. It stays in tight clumps and looks great with cardinal flower, blue lobelia, New England aster, smooth aster and bottle gentian. Showy goldenrod does well in dry soils so it is ideal for the prairie garden or meadow garden. It will work in moist soils as well. As a plant for a pollinator garden I would put it first on the list.
Solidago speciosa - Showy goldenrod
-Beautiful yellow flowers
-Works in dry soils
-Height: 2 to 5 feet tall
-Zone: 3 to 9
(photo credit - www.wildflower.org)