Convincing some gardeners of the landscape value of goldenrods (Solidago species and hybrids) is not always easy. These plants have long suffered from an undeserved reputation as a common field weed that causes hay fever. In fact, ragweed is the primary hay fever culprit. Goldenrod is falsely accused because it flowers abundantly during the peak allergy season.
Most goldenrods are clump-forming plants with erect to somewhat arching stems of varying heights and alternately arranged leaves. Flowers are typically yellow, but there are a few scarce white forms. Individual flowers are very small but are borne in great numbers to form flower heads of various shapes and sizes. Plants bloom over a long period in late summer and fall.
Species and Cultivars
There are more than 120 species of goldenrods. Over 70 of these are native to the US and Canada. Many are well adapted to the midwest. Iowa has over a dozen native Solidago species that are relatively common, as well as a few rare ones.
An interesting prairie species, stiff or rigid goldenrod (Solidago rigida), has gray-green leaves with flat-topped flower clusters atop a rigid stem. Stiff goldenrod often reaches 5 feet tall when in bloom in the prairie.
Dyersweed or gray goldenrod (Solidago nemoralis) grows in open woods as well as dry, upland prairies. Most of our native species are best placed in naturalistic areas of the landscape.
Not every goldenrod fits into all landscape situations. Successful use of these herbaceous perennials depends on careful plant selection. Several goldenrod species, hybrids, and cultivar selections are outstanding perennial garden plants. They are also excellent cut flowers, both fresh and dried. New cultivars and hybrids offer neat, compact growth, as well as a variety of flower forms. Some of the named cultivars include the following:
- 'Baby Sun' --- (Solidago hybrid) 24 inches tall, blooms in July and August
- 'Crown of Rays' --- (Solidago x cultorum) 24 inches tall, columnar plant with large flat flower heads, blooms in August and September
- 'Fireworks' --- (Solidago rugosa) 24 to 36 inches tall, arching sprays appear in September and October
- 'Golden Fleece' --- (Solidago spacelata) 15 to 18 inches tall, ground cover habit, blooms in August and September
- 'Golden Baby' (Solidago hybrid 'Goldkind') --- 18 to 30 inches tall, dense plumes in August and September
- 'Variegata' (Solidago flexicaulis) --- 36 to 48 inches tall, groundcover habit in part shade, blooms in September and October
Goldenrods are fairly easy to grow when sited properly. Plant prairie species in full sun with well-drained soils. Some species like Zigzag goldenrod (Solidago flexicaulis) prefer woodland edges and part shade while the bog goldenrod (Solidago uliginosa) prefers moist marshes and wet meadows. But for the most part, goldenrods are an adaptable group - adjusting to varying soil moisture conditions once established. They are often extremely hardy, drought tolerant, long-lived perennials. They also have few insect or disease problems and require minimal maintenance. In fact, because of their late season of bloom, they are a valuable food and nectar source for pollinators and insects.
Some species and hybrid cultivars will need division every four to five years. Some species reseed freely or have rhizomatous roots with strong spreading tendencies. These species are best divided every two to three years. Division is best done in early spring just as growth commences, but most goldenrods are also easily propagated by tip cuttings taken in spring or by basal cuttings taken in fall.
Updated from an article written by Eldon Everhart that originally appeared in the August 12, 1992 issue of Horticulture and Home Pest News, pp. 137-8.