Showing posts with label Canada Goldenrod. Show all posts
Showing posts with label Canada Goldenrod. Show all posts

Friday, September 24, 2010

Goldenrod

Sections of the field are beginning to flush yellow as the Canada Goldenrod, Solidago canadensis, finally begin to bloom. Goldenrods produce chemicals through the roots that inhibit the growth of certain plants. This reduces competition and allows the goldenrod to quickly spread through underground rhizomes. For this reason, goldenrods often produce almost solid stands.

Goldenrods produce some beautiful flower clusters. Many people shy away from these lovely flowers because they believe them to be the source of their hay fever symptoms. Actually, the goldenrod has heavy pollen that is transported by pollinating insects and leaves most people unaffected. It’s the ragweed that produces the airborne pollen that irritates so many nasal passages. The fresh flowers can be cut and dried to serve as a reminder of autumn’s splendor through the cold winter months.

The mass of flowers is called an inflorescence and is composed of many short branches all bearing tiny flower heads. The arrangement of the flower heads on the branch is one of the characteristics used in goldenrod identification.

Goldenrods probably have the most insect activity of any fall flower. Many insects are goldenrod specific and the goldenrod plant almost becomes an ecosystem by itself. This bloom harbored a collection of aphids of two different sorts. The red individuals are easy to spot, but there’s also a larger type with a green coloration that makes it blend perfectly with the goldenrod stem.

Wasps of all types visit these flowers. I’ve watched various wasp species drink nectar, nibble pollen, chew petals and hunt insect prey on these flowers. This is a wonderful way to view wasps, because they are not protective of the flowers and let you get up close without threat. You’d never be able to get this close to a wasp on its nest without eliciting some type of defensive action.

Crab spiders are everywhere among the goldenrods. This appears to be Misumena vatia, the Goldenrod Spider. Coloration in this species is quite variable and the individuals have a limited ability to change color. The ant rushed over to chase off the spider. You can see how things got turned around.