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This spray of Canada goldenrod Solidago canadensis is part of a big stand of it way in the back part of the yard, and was alive with honeybees Apis mellifera when I took this shot.

Canada goldenrod is the most common and most weedy of the many kinds of goldenrod that occur in our area. It's a classic weed, appearing after a place has been disturbed--by fire, flood, bulldozer etc.--and enjoying the full sun and bare soil. It survives out in the open until the open space becomes enclosed by the shade of shrubs and trees. It may help to delay this succession by putting chemicals in the soil that impede the growth of maples and other plants. Each goldenrod plant has hundreds of flowers attracting insect pollinators as varied as flies, beetles, bees, wasps, butterflies, and moths. The seeds are fed upon by goldfinches and other birds. Goldenrod suffers from the misconception that it is a major cause of allergies--probably a confusion resulting from other, less conspicuous plants that bloom at the same time, such as ragweed.

Honeybees are semi-domestic animals, probably native to India or the Mediterranean, brought to virtually everywhere on Earth by humans. Our species provides artificial nesting places and locates them near crops that need pollinating. These bees are generalists, able to feed on and pollinate thousands of species of plants, most of which are completely alien to them. There are mobile honeybee colonies, dozens of hives put on trucks which drive through the night to service various agricultural fields. In recent years these hives have suffered mysterious losses, likely a combination of various stresses and the effects of pesticides.

I've found that one common perception that has developed from the science journalism about this issue is that "the bees" are disappearing. Why, then, are we being stung by yellowjackets, etc.? It's an educational opportunity.


This is a bee-mimicking fly (anyone know what kind?) on another goldenrod blossom nearby.

Canada goldenrod appeared earlier as 365 urban species #223. In the same entry I wrote about ragweed.

The honeybee was 365 Urban species #194.
urbpan: (dandelion)

A stalk of goldenrod colonizes a roadside planting in the Longwood Hospital area in Boston.


Ragweed by [livejournal.com profile] cottonmanifesto. A sidewalk crack near the same location.

Urban species #223: Goldenrod Solidago canadensis
Urban species #224: Ragweed Ambrosia artemisiifolia

Ragweed and goldenrod are often discussed together. These two plants, both common in urban, suburban and countryside contexts, bloom at around the same time toward the end of the summer. Goldenrod (any of more than a hundred species commonly found in North America) produces showy plumes or crowns of tiny yellow flowers. Often it colonizes a field or lot and turns the whole area into a bright wash of color. When I was growing up, any time anyone sneezed in late summer, some parent blamed the goldenrod. The ubiquitous weed was an obvious scapegoat--doubtless that all that yellow must be producing huge amounts of irritating pollen. Of course, the goldenrod's color is intended to attract insects to mechanically transport the pollen from one place to another, and relatively little goldenrod pollen should be drifting on the air (though it can cause human, and canine, allergy suffering). Instead we can blame those plants with flowers with no attractants for insects--no strong odor or bright color. We can point to many kinds of grasses, and then those weeds with green flowers: mugwort, lambsquarters, and of course, ragweed.

Ragweed is considered the worst allergy-producing pollen. Along with its pollen's virulence, we also must cope with the plant's abundance. Ragweed grows well in the city, in poor soil compacted by foot traffic. It's seeds are high-quality food for birds, notably seed-eating urban species such as rock pigeons and house sparrows, who will spread the plant far and wide.

Native Americans used a tea of ragweed roots to alleviate menstrual pain, and rubbed ragweed on their skin to treat insect bites. As ragweed is known to cause contact dermatitis, one can speculate on its affect on skin already irritated by a mosquito bite. The pollen of at least one species of ragweed (Giant ragweed A. trifida) is harvested to make anti-allergy medication.

Goldenrod also has a history of human association. Reportedly it was used to help heal wounds (resulting in the Genus name: Solidago, to make whole or solid) by the Crusaders. Also, when folks in Boston were angry about a certain tax on imported tea, they made "liberty tea" from goldenrod. I'm frankly skeptical about this last use, as goldenrod is one of the only plants uneaten in the deer enclosure that I maintain at work--and those deer eat poison ivy and garlic mustard. In addition to tea, apparently the blossoms can be fried, like dandelion flowers are, into fritters.

Along with the insects that pollenate them, there are many species of insects that use goldenrod as a kind of nursery. There are spittle bugs, hiding in protective froth attached to the stems, and then there are several kinds of insects that inhabit the stalks themselves, causing the growth of goldenrod galls. Some birds, such as downy woodpeckers and black-capped chickadees are attracted to goldenrod fields, in order to feed on the larvae inside their galls.

more pictures of ragweed and goldenrod )

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