Yesterday, as we returned from an evening walk, a ray from the setting sun picked out a plume of goldenrod against the shade of a line of conifers. The fading light seemed concentrated in the brilliant mass of tiny star-shaped florets.
Look deep into the heart of a goldenrod and you may find a creature – this is a plant that offers abundant pollen and nectar, as well as playing host to the caterpillars of a multitude of insects. Those visiting to collect floral rewards include many species of bees and wasps, the Monarch and other butterflies, syrphid flies and many types of beetles. Also to be found, insect predators like the Ambush Bug or the Crab Spider. The seeds are eaten by birds, including American Goldfinch, American Tree Sparrow, Dark-eyed Junco, and Pine Siskin, as well as mammals like the Eastern Cottontail Rabbit.
Goldenrod (Solidago) came out at the top of a list created by Doug Tallamy, Professor of Entomology and Wildlife Ecology at the University of Delaware and author of Bringing Nature Home
, who studied plants for their contribution to biodiversity on the basis of the number of species of butterflies and moths (Lepidoptera) they support. He found goldenrod plays host to 115 species, followed closely by asters (112), sunflowers (73), with members of the Eupatorium family (Joe Pye Weed, Boneset) coming in at 42.
(Tallamy’s list concentrates on plants used by insect herbivores, e.g. the ones whose larvae (caterpillars) consume the foliage. So for instance, plants like those in the Monarda family (bee balms), that provide nutrients to foraging insects, score lower on this list, hosting only seven species of Lepidoptera. But the bee balms, as the name indicates, are among the most valuable for pollinators.)
It’s not goldenrod that makes you sneeze at this time of year – that’s more likely the Common Ragweed (Ambrosia artemisifolia), a native plant that is of considerable wildlife value because of its nutritious seeds. Ragweed has lightweight pollen that’s wind-dispersed, while the pollen grains of goldenrod are heavy, coated with oils that give off volatile compounds to attract the pollinators it needs to set fertile seeds.
There are those who issue dire warnings against planting goldenrod. Some visitors to my nursery shudder, visibly, when they see the potted solidago. But it is a perfect choice for a spot where the gardener wants a plant to fill and hold the space – if left to take care of itself, goldenrod will do so wonderfully. In sun, combine it with New England Aster (Symphyotrichum novae-angliae) for a stunning end-of-season show. But keep an eye on it if planted with other species in an ornamental garden – most goldenrods are vigorous plants that spread readily by root and by seed. I have planted the Flat-topped Goldenrod (Euthamia graminifolia) in my Monarch Waystation and if I notice it is bullying the nearby Helen’s Flower (Helenium autumnale), I dig it up, divide and downsize. This becomes necessary every couple of years.
In her book, Pollinators of Native Plants
, Heather Holm suggests gardeners plant Stiff Goldenrod (S. rigida) because its root system is fibrous and doesn’t spread rapidly. Also, its gray-green foliage contrasts well with other native prairie plants she suggests as companions – Rough Blazingstar (Liatris aspera), Heart-leaved Aster (Symphyotrichum cordifolium) and Little Bluestem (Schizachyrium scoparium).
For the shade, Blue-stemmed Goldenrod (S. caesium) is not an aggressive spreader and the bright sprays of yellow stand out wonderfully in low light.
Goldenrods are gorgeous and in the right place they are one of the joys of late summer and fall. Below are four of the species you’re likely to encounter in the wild in our area. The descriptions are taken in part from the Guide to Common Plants of Mayer’s Marsh (which is located north-west of Barrie).
-Canada Goldenrod (S. canadensis): 30-150 cm. Small flower rays in curved, one-sided clusters on curved plumes. Stem is smooth near the base, hairy above. Leaves narrow and lance-shaped with toothed edges, veins parallel to the midrib.
-Rough-stemmed Goldenrod (S. rugosa): 30-180 cm. Widely arching branches giving it an ‘elm-like’ appearance. Hairy stem. Rough, hairy leaves are oval in shape, with the midrib the only prominent vein.
-Late Goldenrod (S. gigantea): Up to 210 cm. Arching, curved branches. Smooth, purplish stem covered with a waxy coating that can be rubbed off. Smooth leaves are lance-shaped, sharply toothed, with a prominent vein on each side of the midrib.
-Flat-topped Goldenrod (Euthamia graminifolia): 60-120 cm. Also known as Grass-leaved or Lance-leaved Goldenrod. Part of a group of goldenrods formerly classified in the Solidago genus that were separated because of structural and DNA differences. Flat-topped clusters of fragrant yellow flowerheads atop a smooth or finely downy stem. Narrow, sharply pointed leaves are untoothed, often marked with black spots (no other goldenrod gets these).NB: The Return of the Native nursery re-opens tomorrow (Friday September 9) for the fall planting season. We now have a wider selection of native grasses. Check the plant list for other new offerings.