Wild Side: Goldenrod is misunderstood, blamed for many woes

Goldenrod.
File photo by Susan Safford

Goldenrod.

Perhaps the most characteristic Vineyard plant of late summer and early fall is goldenrod — or actually goldenrods, plural, because more than a dozen species are native to the Island. As you’d expect, different species have different habitat preferences and consequently turn up in different places. But goldenrods all share, to some degree, certain characteristics: a perennial life history, a tendency to spread via underground rhizomes, and of course the eye-catching yellow flowers that give this group of plants its name.

Goldenrods are nearly inescapable on the Vineyard, and the ability of some species to spread and form extensive clones makes them visually dominant in some settings. These plants lend themselves to use in gardens and artificial meadows, but keep their vigor in mind when using them as ornamentals: especially in fertile soils or in the absence of equally vigorous competitors, some of our goldenrods can get a little too aggressive. Meadows and roadsides abound with these plants, and goldenrods have a knack for finding their way even into little snippets of habitat, such as small openings along woodland trails. Sorting out the species can be challenging; important characteristics include leaf shape, the structure of the flower cluster, the number of rays on each individual flower, and the degree of hairiness of the leaves and stem. But some species are quite similar, and I’m frustrated surprisingly often when I try to identify goldenrods to the species level.

Perhaps because they are the most conspicuous wildflowers at this season, goldenrods have been unfairly maligned as the main cause of late-season allergies. Note, though, that the pollen of a goldenrod is sticky, and the individual grains are relatively heavy. These are traits of pollen intended to be transported by insects, not by wind, and in fact goldenrods release very little pollen onto the breeze. (The bright flowers of a goldenrod are in fact a strategy to attract the insect pollinators these plants depend on). You can’t, therefore, blame your sneezing on this goldenrod. A more likely culprit is ragweed, as widespread as goldenrod but possessed of dull green flowers (not attractive to insects) and hence much less visible. A single ragweed plant pumps hundreds of millions of pollen grains into the air; the pollen is said to be one of the strongest botanical stimulants of an allergic response, and that’s the most likely cause of your late summer hay fever.

I’ve always been struck by the sheer hardiness of some of our goldenrods — their ability not just to survive but to flourish in inhospitable settings. The prizewinner in this category is surely seaside goldenrod, which, true to its name, is often found growing on dunes or upper beach within yards of the ocean. This plant produces a formidable root system, helping stabilize dunes and also helping the plant survive disturbance by wind and flood. And the leaves of seaside goldenrod, slightly fleshy and covered with a thick skin or cuticle, help the plant tolerate the desiccating effects of salt spray, full sun, and sandy, unretentive soils. The intense yellow flowers of this species are among the most striking to be found among the goldenrods (and that’s really saying something); seaside goldenrod is an important late-season nectar source for insect pollinators, and, in particular, it’s a favorite of migrating monarch butterflies.

My personal favorite goldenrod, though, is probably sweet goldenrod. This is one of the shorter goldenrods in stature, but its impressive flower heads may constitute a third or more of the plant’s overall height. The name of this species comes from its aromatic foliage — a crushed leaf smells pleasant and spicy, if not exactly sweet. Sweet goldenrod seems to be another particular favorite of insect pollinators; patches of this species that I’ve introduced to my yard are alive with bees, flies, small wasps, and butterflies, and I commonly find five or six different pollinator species on a flower head at the same time. Sweet goldenrod seems to be a widely adaptable plant and may be the best choice for inclusion in a garden; it transplants readily and easily starts from seed.

Another favorite of mine is narrow-leaved goldenrod, a plant of dry or at least well-drained soils that is actually in a different genus from most of our goldenrod species. The leaves are indeed thin, nearly thread-like, and the flowers, although an intense goldenrod yellow, differ from those of most goldenrods by appearing in loose, flat-topped clusters rather than compact spikes. The nectar of this plant must be especially tasty: many types of insects appear to nectar on this goldenrod preferentially, flocking to it while ignoring other goldenrod species nearby.

We’ve probably already passed the peak of goldenrod bloom, but some flowers will persist until a hard frost has shut plants down for the season. Colorful, widespread, and vitally important to our insect pollinator populations, goldenrods are plants to appreciate while their season lasts.