Solidago is definitely not top of the most-wanted list. When asking gardener friends whether they grow this genus, I was met with comments about it "going wild in grandmother’s garden", so it is seen as a problem plant and old-fashioned. However, like most genera with a bad reputation, there are some varieties that buck the stereotype and can be recommended.
There are around 100 species, all herbaceous perennials with erect stems, narrow leaves and terminal panicles or racemes of small yellow flowers in summer and autumn. Most come from North America with a few from South America, Europe, Asia and Macaronesia.
The two species that have given solidago a bad name are S. gigantea and S. canadensis. Both are tall and they spread aggressively, though they do not tend to completely outcompete their neighbours. In fact, used in wilder areas of the garden they can be allowed to romp away and will provide colour and interest as well as attracting beneficial insects.
There are lots of more well behaved and compact varieties available — generally modern hybrids bred from S. canadensis, S. virgaurea or S. brachystachys.
They are very variable in height, ranging from 30cm to 210cm, and all flowering between July and September.
There are dwarf varieties such as S. ‘Goldkind’ and S. ‘Golden Dwarf’; a nice bushy variety S. ‘Goldenmosa’ Award of Garden Merit (AGM), which is a little taller and has fluffy mimosa-like flowers; and very tall varieties such as S. ‘Golden Wings’, which produces golden yellow flowers in late summer. Most of the goldenrods are golden yellow but a few have a lemony tone, such as S. × luteus ‘Lemore’ AGM.
They are easy plants to grow, coping with any well-drained garden soil. But they will be smaller and less vigorous than if given somewhat more fertile, moist conditions. They are prairie plants so best in full sun but they can tolerate light shade.
Sometimes the stems are strong enough to stand up on their own but the really tall species, and those grown in highly fertile soil that hence get top-heavy, will need a bit of discreet staking. They are best mulched in the spring and may need to be watered during dry spells. Plants can be divided in spring or autumn but they are long lived and do not need regular division.
Despite their poor reputation they are useful to combine with other plants, particularly blue-flowered ones such as also late-flowering asters or aconitum as well as daisy flowered rudbeckias and helenium. They add texture to a border with their feathery heads and as foliage turns in the autumn, with hues of red and orange beginning to show, the golden yellow flowers blend in beautifully.
What the specialists say
Neil Lovesey, owner, Picket Lane Nursery, Dorset
"Solidago is an underrated perennial with good, self-supporting stems to 2m topped with sprays of yellow flowers in late summer and autumn. They are very hardy in England and there is a good variety of flower forms, provided by different species and cultivars.
"They are best grown in sun or light shade and are happy in most garden soils. They respond well to the Chelsea chop, so their height can be controlled and shortened. They are easy to propagate and highly attractive to bees, butterflies and other pollinators. They are affected by few pests. They can be susceptible to autumn mildew but this can be easily controlled.
"Although S. canadensis is the normal species grown in our garden, S. rugosa has good bronze foliage in the spring and a much more delicate, open flower form."
Ian Garland, owner, Grangehill Landscapes, London
"I know goldenrods have got a bad name but as they say, ‘right plant, right place’ — if you put the taller ones in a more informal part of the garden it can work.
"Butterflies love them so if you’re creating a wildlife garden it’s a good plant to use. I really like S. rugosa ‘Fireworks’ because it has the height, up to 1.5m, but it spreads slowly and has fantastic sprays of yellow flowers late in the summer or autumn.
"There are quite a few lesser-known species that are beginning to become available in the UK on seed lists. Look out for the North American species S. caesia, which is a delicate looking plant with small yellow flower clusters scattered up red-flushed stems.
"I have also heard that the white-flowered S. ptarmicoides is a nice plant. It’s worth trying new species from seed because they are quite different to the garden varieties we currently know."
Species and varieties
S. cutleri, or the alpine goldenrod, is a very compact plant that produces masses of golden flowers in the late summer and early autumn. Recommended for the front of a border, a rockery, tub or raised bed.
Attractive to bees and butterflies. There is a good cultivar called ‘Goldrush’. Height and
S. flexicaulis is known as the zigzag goldenrod because of its zigzag stem. It has brilliant yellow flowers and finely serrated oval leaves. Height: 30-90cm.
S. glomerata forms low clumps of large bright-green glossy leaves, leafy stems and panicles of single yellow flowers. Height: 90cm.
S. ‘Golden Dwarf’ is a dwarf variety that suits the front of a border and has frothy yellow flower plumes from July to September, ensuring late-summer colour. The flower heads are ideal for use as cut flowers and will last more than a week indoors. Height: 30cm.
S. ‘Goldenmosa’ AGM (H7) is a modern compact hybrid with large sprays of golden mimosa-like flowers that last throughout late summer and early autumn. Also features strong stems that do not need staking. Height: 75cm.
S. ‘Goldkind’ is a compact form with deep-yellow conical sprays of flowers between July and August. Suits the middle of the border. Makes a good cut flower. Height: 60cm. Spread: 30cm.
S. × luteus ‘Lemore’ AGM (H7) is a compact form with narrow mid-green leaves and panicles of light-yellow daisies. Height: 60cm.
S. rugosa ‘Fireworks’ AGM is a striking, late-flowering cultivar with flower clusters that radiate out in all directions, resembling streaming yellow fireworks. Height: 90-120cm.
S. sphacelata ‘Golden Fleece’ is a short, neat cultivar that creates good ground cover. Dense panicles splay upward and outward, resembling a mass of elegantly bunched bouquets. Height: 30-90cm.
S. virgaurea is a species with medicinal qualities that is used to treat problems with the kidney or bladder. It has tall stems bearing arrays of numerous small yellow flower heads. Flowers from July
to October. Height: 60-100cm. Spread: 40cm.
Thank you to Floramedia, which supplied the images for this article from its photo library