Ragweed looks like a fairly nondescript weed, usually with fernlike or larger green leaves. It’s a plant many people know by name because it’s a prime source of fall allergies in North America. It starts blooming in the late summer, usually in August, and goes through till November, with the highest pollen month being September.
Read on to learn more about ragweed and how to identify the two types by their leaves and flowers.
Fast Facts
- Common ragweed’s scientific name is Ambrosia artemisiifolia and giant ragweed’s scientific name is Ambrosia trifida. Common ragweed often is easily confused with some other plants, such as mugwort,
- Ragweed is part of the Asteraceae family.
- Ragweed grows tall and has nondescript flowers and ragged or palm-shaped foliage.
- Ragweed seeds are beneficial wildlife food.
- Ragweed has the life cycle of an annual summer weed.
Types of Ragweed
There are two main types of ragweed: common ragweed and giant ragweed. Common ragweed grows to 6 feet tall with a fernlike appearance. Giant ragweed grows to a staggering 15 feet tall with leaves shaped like the palms of hands. Both types of ragweed have other identifying characteristics.
Common Ragweed Leaves
The leaf of the common ragweed plant has a fern-like appearance. Young leaves typically have some purple speckling on them. However, other weeds, such as lamb’s quarters, can also have purple markings.
The Spruce / K. Dave
Common Ragweed Blooms
The Ambrosia genus of which ragweed is a part belongs to the aster family but common ragweed blooms, which appear as small, yellowish bumps, are exceedingly inconspicuous. The flowers are followed by unremarkable brownish fruits.
The Spruce / K. Dave
Giant Ragweed Leaves
Giant ragweed bears leaves that resemble the shape of a palm of a hand. The leaves usually have serrated edges, and their green stems are covered in tiny white hairs. Plus, the smaller leaves around the base of the plant often have hairs on their undersides. Overall, the leaves can be up to a foot long and 8 inches across.
The Spruce / K. Dave
Giant Ragweed Blooms
Giant ragweed flowers are similar to common ragweed flowers. Many of the upper stems of the plant grow a flower spike that is cylindrical and roughly 3 to 6 inches long. The plant also will often have slightly smaller flower spikes closer to its base. Like common ragweed, the blooms appear like small bumps. The flowers start green but turn yellow-green and then yellow-brown color as they mature.
