Culture
Winter hardy to USDA Zones 6 (perhaps Zone 5) to 9 where it is easily grown in medium moisture, moderately fertile, well-drained soils in full sun to part shade. Avoid dry soils. This plant appreciates some part shade in hot summer areas. Prune if needed in late winter to early spring. Propagate by cuttings.
Noteworthy Characteristics
Aristolochia clematitis, commonly called birthwort, is a rhizomatous, deciduous, non-climbing perennial of the birthwort family that typically grows to 2-3’ (infrequently to 4’) tall on stems clad with heart-shaped leaves (to 4 1/2” long). Apetalous (no petals) greenish-yellow flowers bloom from late spring to early summer (June-July) in clusters from the leaf axils. Each flower (to 1” diameter) has a straight funnel-shaped tube with pointed, curved upper lips (considerably different in appearance from the curved Dutchman’s smoking pipe-type blooms found on some other species in the genus). Flowers are pollinated by certain tiny insects. Each pollinated flower is followed by a 6-valved seed capsule.
This birthwort is native to Europe, but has been introduced into and naturalized in a few parts of North America including Quebec, Ontario and New York to Ohio and Maryland where it is most commonly found in the wild along roadsides and in waste places.
This European species was used by medieval midwives following the medieval Doctrine of Signatures under the belief that God had marked plants in such a way that doctors could recognize from plant appearance what diseases the plants were able to treat. The womb-like appearance of some birthwort flowers led to the belief that this plant would help treat problems of childbirth. Accordingly, juice from plant stems, which contains aristolochic acid, became commonly used as a medicine during labor, hence the common name of birthwort. Today, it is known that aristolochic acid is very poisonous to humans (regular ingestion of very small amounts can cause both urinary tract cancers and kidney failure). In 2001, the FDA warned that no herbal medicines containing aristolochic acid should be used.
Aristolochia plants are the host for the pipevine swallowtail butterfly. Eggs are laid on plant leaves. Eggs hatch and the plant leaves become the sole food for the emerging larvae (caterpillars). Leaves contain poisons which make not only the larvae but also the subsequent butterflies poisonous to predators.
Genus name comes from the Greek words aristos meaning best and locheia meaning childbirth or delivery in reference to the fact that plants of some species within this genus (1) have a flower structure which more closely resembles a human fetus in the womb than a pipe, and (2) served in the past as the source of ancient plant preparations used for treatment of pain and infections incident to childbirth.
Specific epithet means resembling Clematis.
Problems
No serious insect or disease problems. Root rot, leaf spot and southern blight may occur. Can be an aggressive spreader in optimum growing conditions.
Uses
Interesting plants, but flowers lack the conversation-piece quality of the Dutchman pipe type blooms. Best ornamental feature of this plant is the attractive foliage. Best planted in small groups. Borders. Naturalized areas.