Bowiea volubilis subsp volubilis is a deciduous climber which climbs to 3-4 m in surrounding vegetation or scrambles over rocks on hillsides.
The bulb is large, reaching 150 mm in diameter, with several fleshy white scales becoming greenish-yellow if exposed. The bulbs, like onion and tulip bulbs are comprised of tightly clustered modified leaves which serve as reserves of nutrients and moisture.
Periodically, plants will produce long "vines", which are actually the plant’s inflorescence, which in this species are intricately branched, and are either climbing or scramble along the ground and onto nearby plants. These "vines" can grow quite large (in some plants, upwards of 15 feet in length). These do not produce true tendrils or other structures which may anchor or attach the vines to other plants, so the vines can only stay in position by weaving their way through the stems of other plants. Stems are fleshy, bright green, much branched and function as leaves.
Flowers are 16-24 mm in diameter, green, with stalks turning backwards. Fruits are in the form of a brownish oval capsule, about 25 mm in diameter.
The best medium for growing climbing sea onion is a gritty, well-draining soil mixture. Combine half potting soil and half sand. Choose a pot with drainage holes, as excess moisture can make the bulb rot.
Climbing sea onions like to be in a crowded pot, so select one that’s just barely larger than the bulb. Place the container in full, but sheltered, sun or partial shade. Excess heat will cause the bulb to callus over and become dormant, while consistent even warmth and moderate moisture will allow the plant to grow all year.
Depending upon growing conditions, the bulbs may be uniformly pale green, or may be covered or partially covered with the dried remnants of outer leaves (much like an onion skin). In time, these bulbs eventually split to produce two bulbs: over a period of many years, some plants can produce numerous offsets, while others will tend to remain solitary, only producing offsets after its bulb has grown quite large. Divide the offsets when they are half the size of the parent plant and pot them up in the same soil mixture.
Climbing Onion makes an attractive pot plant or hanging baskets - allowing the stems to arch over the sides, for a shady area, both indoors and out.