Orange String on Everything

Vine on a vine: Dodder on porcelain berry, 26 July 2022 (photo by Kate St. John)

4 August 2022

By the end of July in western Pennsylvania, there are patches of orange string draped over plants in moist locations on the edge of the forest. The orange strings are dodder (Cuscata), a native annual parasitic vine that blooms from July to October.

Dodder wraps itself around its host and inserts tiny haustoria to suck out water and nutrients. Last week I found it parasitizing invasive porcelain berry — Go, dodder! — but dodder won’t beat back the grapevine. Dodder doesn’t kill its host.

Orange string on everything: Dodder wrapped on invasive alien plants, 26 July 2022 (photo by Kate St. John)

Look very closely and you can the haustoria clinging and dodder’s tiny flowers that are pollinated by wasps.

Dodder in bloom (photo by Esther Allen)

Dodder will die at the end of the growing season yet you may find it in the same spot every year. Find out why this happens and other interesting tidbits in this vintage article.

(photos by Kate St. John and Esther Allen)

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