Thursday, September 23, 2010

LOOK FOR: Goldenrod (It's Not Causing Your Hay Fever)

I grew up thinking goldenrod caused my fall allergies. They're flowering, I'm sneezing. Case closed, right?

Goldenrod (Solidago canadensis)
Solidago canadensis by 'Metrix X'

In fact, it's a classic case of being in the wrong place at the wrong time. If you read last week's post, you know the main culprit in hay fever: ragweed. Goldenrods just have the misfortune to be much more showy right now, while subtle old ragweed is churning out its pollen grains of misery.

Don't believe it? If you stand by a goldenrod plant for any length of time, you'll see: these flowers are pollinated by insects, not wind. Their pollen is only headed up your nose if you stick it right in there with the bees. (If you do that, goldenrod still might make you sneeze. But at that point, it's your fault.)

There are hundreds of species of goldenrod, and dozens in the Mid-Atlantic. All have tiny yellow flowers that look like miniature daisies on close inspection. The flowers are often in long "wands," but sometimes in small clusters or on branches.

Grey Goldenrod
Grey goldenrod (Solidago nemoralis) by 'milesizz'
Blue-stemmed Goldenrod
Blue-stemmed goldenrod (Solidago caesia) by 'milesizz'

There are several species of insects that are closely associated with goldenrods; they've either adapted coloring that works well with the flowers, or they've evolved to only be able to eat goldenrod at some stage of their life cycle. As you might imagine, some of them have some pretty amazing coloration, like the goldenrod crab spider (Misumena vatia) and the goldenrod bug (Megacyllene robiniae). It's worth stopping to look closely and see who you can find among those little flowers.

Spider in the Goldenrod
Goldenrod spider by 'Lady-bug'
Megacyllene robiniae, Locust borer, Goldenrod bug
Goldenrod bug by 'Flatbush Gardener'

In the wild: Goldenrod grows all over, with different species favoring different conditions. There's always a good showing at Lake Artemesia (join us on a walk there on October 9)...what's your favorite patch?

In your yard: Many species are easy to grow; in fact, a little too easy sometimes. Cullina warns against S. canadensis and S. graminifolia as being too aggressive. Out of the ones we've tried in our yard, anise-scented (S. odora) and zig-zag (S. flexicaulis) seem best behaved.