A very large cousin of the Common Ragweed reaching over 10 feet tall. Produces abundant pollen causing allergy problems.
Plant Type
All Plants, Weeds
Sunlight
sun to semi-shade
Moisture
prefers moist, very tolerable
Soil & Site
prefers moist, very tolerable
Flowers
Separate male and female flowers are on the same plant (monoecious). Male flowers are abundant up and down the side of the spike (racemes), female are in the axials of the lower leaves. Flowers are green with yellow pollen. Pollinated by air-bore pollen.
Leaves
Leaves usually 3 lobes occasionally 5, entire or palmately cleft and opposite.
Dimensions
I have seen these plants over 10 feet in moist areas. Reported to reach 15 feet.
Misc Facts
Ambrosia means "Food for the Gods", how this wretched plant obtained this name is beyond me. Europe, found through out most of the USA
Author's Notes
During the "season for sneezin", the people afflicted with Hay fever, blame their problem on the stately Goldenrod. They sneeze, see the yellow flowers of the Goldenrod and put two and two together and get five. The pollen of the Goldenrod is heavy and doesn't cause allergy problems. The Ragweed’s pollen is very light and is one of the main vectors of these problems. I always show this plant to my Horticulture classes, they are surprised to learn what really causes hay-fever, and even more surprised to see how big this plant gets as compared to the common Ragweed.
Notes & Reference
#14-Hedge maids and Fairy Candles (Jack Sanders), #19-Common Weeds ( USDA Agricultural Research Service)