Aristolochia macrophylla
[ Isotrema macrophyllum¹ ]

Pipevine, Dutchman's Pipe

[ click on any image below to see larger version ]

Family: Aristolochiaceae (Birthwort family)

Mid-Atlantic bloom time: May - June
Mid-Atlantic fruit ripe: August - September

Pipevine is a perennial vine that can grow up to 9 meters long, with large (up to 40 cm long and wide) heart-shaped leaves. Its yellowish-green flowers have three lobes, with a corolla tube opening colored brownish-purple. Their fragrance attracts flies and gnats which crawl inside the tube and fertilize the flowers.

Pipevine gets its common name from the shape of its 4 cm long flowers that resemble old Dutch smoking pipes. The plant produces aristolochic acids which have been shown to cause kidney damage and liver cancer in humans. Its leaves are one of the primary food sources for Pipevine Swallowtail butterflies (Battus philenor) (the other foodsource is the related Virginia Snakeroot (Endodeca serpentaria)). The butterflies sequester the acids as a defense mechanism.

Pipevine has been planted ornamentally to cover an arbor or trellis for shade.

15 May 2026 Gainesville, VA	7 May 2025 Reddish Knob, Rockingham County, VA	15 May 2026 Gainesville, VA	15 May 2026 Gainesville, VA (developing flower)
15 May 2026 Gainesville, VA	15 May 2026 Gainesville, VA	15 May 2026 Gainesville, VA (detail of corolla throat)

References

1:   Weakley, Alan S., et al. (in "Studies in the Vascular Flora of the Southeastern United States: VI." Journal of the Botanical Research Institute of Texas, vol. 14, no. 2, 2020, pp. 199–239) assert that subgenus Siphisia of Aristolochia should be its own separate genus Isotrema, referencing the following paper:

Xin-Xin Zhu, Xiao-Qin Li, Shuai Liao, Cheng Du, Yuan Wang, Zhang-Hua Wang, Jing Yan, Yun-Juan Zuo, Jin-Shuang Ma. "Reinstatement of Isotrema, a new generic delimitation of Aristolochia subgen. Siphisia (Aristolochiaceae)." Phytotaxa, Vol. 401 No. 1: 10 April 2019    [ >> link to PDF ]

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