Goldenrod

The bright-yellow plumes of the Solidago species that wave gracefully along roadsides and in waste areas from July until November have only recently drawn the attention of American gardeners. Northern Europeans have recognized the ornamental properties of goldenrod for years; they use them liberally to enliven gardens in autumn. Unlike many tall flowers, goldenrod grows sturdy and upright, thus requiring no stakes. Plant forms tend to improve under cultivation, but some goldenrod can become aggressive and weedy in rich soil. Flower heads make long-lasting cut flowers. Dried sprays are particularly useful in herbal wreaths and fall wall ornaments.

This showy plant should be a prime candidate for late-season color in perennial plantings, but goldenrod has been maligned and, therefore, shunned by most American gardeners. Goldenrod is so conspicuous, it usually gets the blame for fall hay fever. Actually, ragweed (Ambrosia sp.) is the major culprit of nasal distress. Ragweed blooms at the same time as goldenrod, but its small, dull, yellow-green flowers do not attract the eye of humans, nor many insect pollinators. For fertilization, ragweed produces large quantities of light pollen that are carried by the wind to other plants. By comparison, goldenrod pollen is too heavy to be airborne long, and bees are the principal pollinators.

Over 125 species of Solidago grow in the United States. Some common natives have good ornamental qualities:

• Solidago speciosa (showy goldenrod) - it forms large, club-shaped, terminal flower clusters on 5- to 6-foot stalks.
• S. rugosa (rough-leaved goldenrod) - occurs in low woods and meadows. Its long, arching, flower sprays are displayed on 4-foot stems. Plants spread by rhizomes and need plenty of room (at least 3 feet in all directions) to avoid crowding out other plants.
• S. altissima (tall goldenrod) and S. gigantea (giant goldenrod) - can fill out an area rapidly. Both can grow to 7 feet and are excellent for naturalizing sunny banks.
• S. odora (sweet goldenrod) - a native of open woods and dry meadows, exudes an anise scent when bruised. It is a short species (2 to 3 feet) that blossoms early.

Garden catalogs feature few varieties of goldenrod for sale. Most of these are hybrids of S. canadensis, native to eastern North America, and S. Virgaurea, a species found in Europe, Asia, and northern America. Division of mature plants can be made in early spring every three to four years. Big plants will separate into 30 or more pieces, making division the easiest way to propagate goldenrod.