Giant Ragweed as Pest

Sep 1, 2018

Credit SC Public Radio

Hello Gardeners, I’m Amanda McNulty with Clemson Extension and Making It Grow. Feel free to bring flowering stems of goldenrod indoors – with insect-disseminated pollen it doesn’t cause allergies. It’s ragweed that makes copious amounts of nose-tickling pollen so light weight that winds blow it far and wide. Our most common ragweed is Ambrosia artesimifolia (no one seems to know why it’s called Ambrosia – the food of the Gods), and usually it tops out at a couple of feet. But in the upper half of the state, on heavier soils, giant ragweed thrives as a major pest. It easily gets over ten feet tall and makes pollen and seeds in even more massive quantities than its shorter relative. Ragweed seeds are tiny, with a beak that helps them stick to other surfaces, and now these native ragweeds are noxious weeds worldwide as they’ve been uninvited hitchhikers in grain shipments delivered to other countries.