Billowing, brilliant goldenrod among purple asters is a classic native plant combination that is the glory of late summer and early autumn in North American meadows and along roadsides. But it's a scene that hasn't been easy to duplicate in gardens. Most native goldenrods (Solidago species) are too big to fit comfortably with other perennials. As if that wasn't enough, some of the most common species are highly invasive plants. Planting Solidago canadensis among other flowers is like planting a mint that gets 5 feet tall. Fortunately, the situation is changing. Some of the better clump-forming natives are appearing at nurseries and in catalogs. A couple of excellent selections have been named and more are likely to follow.
Until recently, the only well-behaved goldenrods available were varieties of the European species, S. virgaurea. But these bloom in midsummer and finish well before the New England and New York asters begin their late-season display. Although the European varieties are certainly worth growing, it's the newer varieties of American species that produce the stunning fall effects.
It's worth repeating that goldenrod is not the cause of hay fever or other pollen allergies. The real culprit is ragweed, an inconspicuous plant that releases pollen while goldenrod is in bloom. That inaccurate bit of folklore is slow in dying, and is one reason goldenrod is not more popular in American gardens.
The varieties described below are well adapted to North American conditions and will bloom in late summer and early autumn. Most are hardy from USDA zones 4 to 7, and some will certainly prove hardy farther south as they are planted more widely. We've included their native ranges to give you an idea of which ones to experiment with. This selection of goldenrod species and varieties includes some of the best choices available today.
Zig-Zag Goldenrod (Solidago flexicaulis) This shade lover is native to rich woodland soils. It's not as showy as the familiar sprawling giant, Canadian goldenrod but plants that provide late-season color in dry shade are worth their weight in, well, gold. The pretty little yellow flowers are borne along the stems in the leaf joints. This species grows wild from Nova Scotia west to North Dakota in the North and between Georgia and Arkansas in the South.
Grey Goldenrod (S. nemoralis) Never more than 2 feet tall, grey goldenrod is comparable in height to the European varieties. The distinctive greyish cast of the leaves is the origin of its common name. The plants only live a few seasons but readily reseed themselves. Native to poor, dry soils, grey goldenrod does well in sandy soil. In richer flower border soil, grey goldenrod may not reseed dependably. But that problem is easily corrected by saving your own seed and sowing it in well-drained, dry potting soil. This species is available from nurseries only as seed, not plants. In nature it is widely distributed, from Nova Scotia to Alberta and southward from Florida through Texas.
Ohio Goldenrod (S. ohioensis) This is one of the best species for the sunny flower border, if you are looking for a big, showy, late-season goldenrod that is also well behaved. It does well in soils rich with organic matter. The flower heads are large, spreading domes above stalks that range from 2 to 4 feet tall. Ohio goldenrod has excellent disease-free foliage, too. It is widely adapted though its native range is only around the Great Lakes, and between western New York and southern Ontario down to Wisconsin, northern Illinois and Michigan.
Stiff Goldenrod (S. rigida) Late-blooming stiff goldenrod is another clump-forming native that merits a spot in the back of the border with other large plants. Even though it's 3 to 5 feet tall, it won't flop gracelessly onto its neighbor. And it won't run rampant. Stiff goldenrod grows well in a wide range of soils in full sun. Its brilliant yellow flower clusters were once a common sight across the American heartland. This plant is native from Connecticut west to Alberta and from Georgia to New Mexico.
Fireworks Goldenrod (S. rugosa 'Fireworks') Twenty-two years ago, this plant arrived at the North Carolina Botanical Garden in a spadeful of soil dug to preserve savannah plants on a site about to be bulldozed for construction in coastal North Carolina. It produces a spectacular spray of arching branches, each covered in a thin row of yellow flowers. The effect is like a cascade of trailing fireworks. The plant gets 3 to 4 feet tall, about a foot shorter than average for the species. It grows best on moderately fertile soils in full sun. Native from Newfoundland to Michigan southward from Florida into Texas.
Showy Goldenrod (S. speciosa) Showy goldenrod makes elegant mid-sized clumps topped with 12-inch spires of bright yellow. It grows on loam to very light sand, usually reaching 2 to 3 feet tall. It is native to prairies, fields and open woodlands, from southern New Hampshire west to Wyoming and south from Georgia into Texas.
A strain of S. speciosa is called "sweet goldenrod" because the stems are sweetly scented if handled. It is slightly shorter-about two feet-than average, but otherwise is similar in looks and in growth requirements.
Golden Fleece Goldenrod (S. sphacelata 'Golden Fleece') This variety also originated in North Carolina, but was introduced by the Mt. Cuba Center for the Study of Piedmont Flora near Wilmington, Delaware. Unlike the species, which reaches to 4 feet tall, 'Golden Fleece' splays its 15-inch stems out over the soil and makes a loose ground cover about 6 inches tall for the front of flower borders. The foliage is vigorous and healthy. Clumps enlarge slowly, about 4 to 6 inches a year. The large round flower heads are effective for at least a month. The plant grows well in a sunny location in average garden soil. It is worth trying outside its native range, which is narrow: from southern Virginia west to southern Indiana, south to Georgia and west to Alabama.
European Goldenrod (S. virgaurea) There are 30-some varieties of these compact, clump-forming goldenrods. They look like miniature versions of the ubiquitous and huge Solidago canadensis. But they are tidy plants, most topping out at around 2 feet. Some long-established cultivars are 'Baby Sun', 'Crown of Rays', 'Cloth of Gold', 'Golden Mosa', and 'Peter Pan'. Any of them are worth trying. But remember, as garden plants they need to be babied-give them good soil improved with organic matter and a regular supply of water. And they bloom in midsummer, not at the end of the season. They are native to Europe, Asia, and North Africa.
All the Solidago species are very easy to grow. They are relatively pest and drought tolerant. As with most fall-blooming plants, they are best planted and divided in spring. Rejuvenate the clumps by dividing every 4 to 6 years. Dig the plant with a fork and carefully break the clump into pieces with four or more shoots each.
As your crop of goldenrods increases, you'll be able to use them liberally to bring brilliance to the late border. Goldenrods are the perfect match for the other fall classics: Sedum 'Autumn Joy', any of the myriad asters or Eupatorium, the deep purple Vernonia or the aster-goldenrod hybrid, Solidaster. Species, such as S. rigida, are best in naturalistic gardens. Many goldenrods make excellent cut flowers.
Jack Ruttle is a former editor at National Gardening.
Photography by Sabin Gratz/National Gardening Association
Article published on June 23, 2008.