Strophanthus: Beautiful, Fragrant, and Deadly—The Twisted Cord Flower

The name Strophanthus means "twisted cord flower," referencing the wavy, string-like petal extensions cascading from many species. This diverse genus includes vines, shrubs, and trees—all stunning, fragrant, and dangerously toxic.

Notable Species

Strophanthus gratus (Climbing Oleander / Rose Allamanda): 2-inch pink-flushed white flowers resemble oleander. It has "eyelashes" but no long strings. Blooms late winter to early summer with rose-like scent. Needs full sun, post-bloom summer pruning, and careful watering to avoid flower spotting.

Strophanthus preussii (Medusa Flower / Spider Tresses / Poison Arrow Vine): White, melon-scented flowers (~½ inch) age to yellow with rust throats and dramatic streamers. Blooms late spring through autumn in morning sun. Prune in late winter. The name "poison arrow vine" is well-earned.

Extreme Toxicity

Strophanthus species produce cardiac glycosides historically used as arrow poisons and in traditional medicine—the stuff of Sherlock Holmes mysteries. All parts are highly toxic. This is not a plant for households with curious children or pets.

Cultivation Requirements

Hardy only in USDA zones 9+, most require winter protection indoors. Many are semi-deciduous, dropping leathery leaves in winter—don't mistake dormancy for death. Prevent root rot with well-drained soil in terra cotta pots, reduced winter watering, and "jungle conditions" during growth: fertile soil, high humidity, ample water.

Propagation

Seeds germinate erratically (9 days to 2 months at 77°F, sown ⅓ inch deep in sandy mix). Cuttings or mature plants are strongly preferred. My S. gerrardii seedlings made minimal progress over years.

Final Caution

I've grown many poisonous plants safely, but strophanthus's combination of seductive beauty and extreme toxicity demands absolute caution. Avoid it if children or pets access your growing space.

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Photo credits: Mokkie (S. preussii), Kenpei (S. divaricatus), lkiwaner (S. kombe), seedpicker_TX (S. gratus), M. Smith (S. petersianus from 1894 Curtis's Botanical Magazine).