Meet the Natives: Goldenrod


IT DOESN'T CAUSE HAYFEVER. Because it blooms at about the same time as ragweed, goldenrod (Solidago spp.) is unfairly blamed for a lot of red eyes and runny noses. But goldenrod is not the culprit. In fact, grains of goldenrod pollen, being both large and sticky, must be carried around by insects; this means that they are not windborne, thus are highly unlikely to end up in your nose and sinus passages, thus are even unlikelier to cause any irritation of same.

Now that we've disposed of the leading cause of prejudice against goldenrod, let's talk about all the ways in which it is a wonderful plant.

There are many species of Solidago (16 in my province alone), almost all of them with bright yellow fall flowers that are highly attractive to pollinators, especially bees. The goldenrods are notoriously difficult to tell apart, especially since they can hybridize with one other. Of the wild goldenrods, however, perhaps the most beautiful (and also one of the more common) is Canada or tall goldenrod (S. canadensis), which is shown in all the photos on this page. The sight of those brilliant gold plumes, on top of plants that can grow as tall as 6 feet, is one of the glories of late summer and early fall in almost every state and in much of Canada.

Left: Wild goldenrod naturalizes well (some would say too well). The attractive, thick mass of goldenrod on this slope leading down to my pond will help to hold the soil and prevent weeds from taking over.

Wild goldenrod can be extremely useful as a groundcover: It spreads readily, can be mowed (and will even bloom after mowing, at a height of about 8 inches), is tough enough to take foot traffic, and has the interesting property of suppressing germination of seeds in the surrounding area, making it particularly useful for weed control. On top of all that, it provides pollen for pollinators, feeds the caterpillars of several butterflies and moths, and makes a good cut flower.

Left: Although somewhat unruly, wild goldenrod can give a splash of yellow to wilder corners of the garden in late summer. In this corner, the purple coneflower (Echinacea purpurea) and wild bergamot (Monarda fistulosa) were planted, but the goldenrod, yarrow (Achillea millefolium), and anise hyssop (a nonnative) all volunteered.

Goldenrod has been appreciated by English gardeners since the 18th century. Like so many other North American natives, however, it did not become popular with American gardeners until the last few decades.

Even so, most gardeners shy away from wild goldenrod, which will readily take over any area to which it's introduced or to which it introduces itself (as it spreads quite well from seed). While they might let it naturalize in a sunny meadow, most gardeners prefer to keep goldenrod out of perennial borders; even native-plant enthusiasts think twice about including goldenrod in plantings, if they hope to be able to keep their less vigorous native plants.

Not so the many cultivars of goldenrod, however. These are a boon to the goldenrod-lover who would also like to grow something else. Well-mannered cultivars suitable for gardens include "Early Bird" (an early bloomer, as the name implies), "Leraft" (dwarf), and "Wichita Mountains" (also short). Some others I find particularly interesting are:
  • "Crown of Rays" (aka "Strahlenkrone"), apparently a cultivar of S. canadense, is compact, and the flower heads bow over so that they are almost parallel with the ground. When the flower heads are dense enough, they resemble golden rays of sun.
  • "Fireworks," a cultivar of S. rugosa that was developed in collaboration with the North Carolina botanical garden, typically grows 3-4 feet tall. "The 3-foot-tall stems are unbranched for about 2/3 of their length. Then suddenly, they explode into many slender side shoots, each of which in turn carries an explosion of axillary branchlets coated with tiny yellow flowers. The effect is that of a star-shaped firework that continues to open outward in successive explosions," writes Mary Hirshfeld in an article at the Cornell University website, which also has a nice picture of the plant.
  • "Golden Fleece," a cultivar of S. sphacelata, was found growing wild in North Carolina. "Its flowering branches cascade in a lacy network over a rosette of scalloped, semi-evergreen leaves," according to Susan McClure writing in Flower & Garden magazine in December 1996. (As you can see, these cultivars bring out the poet in garden writers.) This one was named a "plant of merit" by the Missouri Botanical Garden.
  • "Golden Baby" is my favorite goldenrod for the perennial border. A short form of S. canadensis, it reaches only about 2 feet, with an unusually long bloom time. To me it looks like an exact duplicate of my favorite wild goldenrod, only in miniature.
  • "Goldrush" is a cultivar of S. cutleri, a naturally short goldenrod that is native to mountains in New England. The cultivar, developed in 1998, forms mounds that are about a foot tall but can grow to 30 inches in width.
  • "Gold Spangles," a hybrid, is not only short (2 foot) but also has gold-splashed foliage.
A word of warning: Not all goldenrods or goldenrod cultivars are native to North America. Though its cultivars are often sold in North America, S. virgaurea is European. As far as I've been able to find out, the popular cultivar "Peter Pan" is of this European origin. If you are trying to maintain a native garden, you will want to try to stay away from the European solidagos. I would also be inclined to avoid them out of concern that they could spread into natural areas or hybridize with local natives.

Goldenrods will grow almost anywhere that has full sun. S. canadense and most of the cultivated goldenrods like moist soils as long as they are not waterlogged.

Some goldenrod trivia from the Wikipedia:
  • Goldenrod can be used to make several shades of natural dye.
  • When caterpillars try to eat goldenrod, the plant defends itself by forming a hard bulb or gall around the insect. Some wasps have learned to lay eggs in these galls; the wasp larvae use the caterpillars for food. Woodpeckers have learned to open the galls and eat both the caterpillars and the wasp larvae. (And the beat goes on!)
  • Pure goldenrod honey is light colored and has a spicy taste. If it's mixed with nectar from other fall plants, however, the honey may be dark and strong.
  • Goldenrod is a natural source for a sturdy, long-lasting rubber. The inventor Thomas Edison developed a 12-foot-tall goldenrod that produced large quantities of this product.


4 comments:

jodi said...

ah, goldenrod. I spring to its defense on a regular basis (yes, to do with those notions of allergies, which I correct, like you do). I like it just fine in the wild parts of our property, down by the pond, along the edges of the pasture, and so on. I don't care for it mixed in my perennial border because it can be a bit pushy, as you also observe. Mostly it's a question of coloursense--that shade of yellow I like just fine in small doses but not a lot of it in my garden, and it is too linked also to the whole end-of-summer malaise. If I could find 'Fireworks' around here, I'd plant it promptly, because I love the look of the plant--but I've never seen it, to my knowledge.
I like the creamy white solidago best myself, but they're all welcome on most of our place. I was watching bees bouncing on a few the other day, and they were definitely having fun!

Wild Flora said...

Hi Jodi,
I confess ... I love that brilliant goldenrod yellow. Love it, love it, love it. I still remember the first time I saw a late afternoon sun shining through a wand of "Golden Baby" that I had planted in my garden in Redmond. I was transported. You can imagine my reaction on discovering that the fields here are full of the full size version! "Wild Flora" is not one for subtle colors, I guess. : )

Puddock said...

Interesting post Flora. btw You're it! http://theviewfromthepond.blogspot.com/2007/09/random-8.html

FalconRider said...

Hi there -

I'd just like to point out that goldenrod doesn't form galls around caterpillars to prevent herbivory. Plants are not that fast, and caterpillars can move.

Galls - aberrations along the stem - are formed by parasites that deposit their larvae into the stem. The larvae emit chemicals which influence the plant to grow around them. The plant serves as a food source for the larvae as well as protection for the pupae stage. Some parasites have actually managed to parasitize the goldenrod parasites. They pierce the gall and either lay their own eggs or eat the larvae inside.