Zygosicyos (2009)

By Mike Cushner (July 2009)

The genus Zygosicyos, from the Greek “zygos” (yoked, joined) and “sicyos” (cucumber), belongs to the Cucurbitaceae – a family of plants that includes the melon, the pumpkin and the watermelon. It’s unclear to me how many Zygosicyos species are currently accepted by botanists. Two appear repeatedly as items of commerce: Z. tripartitus and Z. pubescens.

These caudiciform plants are native to mountainous slopes in Madagascar, where they grow in temperate climates and rich soil. Their foliage is typically described as green creeper vines with tendrils and leaves. Their caudexes are variable in shape from globose to egg-shaped and frequently have a flattened base.

In habitat, they are reported to get “little water and not much sun.” Their caudexes become desiccated during cool weather (dormancy) and tend to plump up as the weather warms if adequate water is available. As the growing season ends and the weather cools again, vines may drop their leaves.

Recommendations in the open literature for cultivation of these plants vary widely in regard to sun and moisture. They are reported to accept full sun if care is taken to acclimate the plants to increased exposure to sun. During the growing season, these plants can take a good deal of water during active growth, and should be watered only “when not dormant.”

A well-draining growing mix and the use of fertilizer during the growing season is recommended. One author recommended that they be kept “dryish” in winter and that Z. tripartitus should be over-wintered in the greenhouse at temperatures over 54 degrees F, avoiding temperatures lower than 41 degrees.