It's not from the sea, and it's not an onion. Known scientifically as Bowiea volubilis, the sea onion is native to the arid regions of eastern and southern Africa, and some might say that it thrives on neglect. With its long climbing stems, the sea onion, a member of the lily family, is certainly quite an oddity, which makes it one of the more interesting houseplants.
The light green base, or bulb, of this plant bears a strong resemblance to an onion. Unlike many other bulbs, the bulb of the sea onion does best if it is only half buried in the soil. If it is buried too deep, there is more of a chance that it could rot. Because these are very long-living perennials, the bulb of the sea onion has been known to grow to be very large, sometimes reaching a diameter of 10 inches (25.4 centimeters) or more.
Leaves of the sea onion are small and very short lived. They look like the leaves of an onion and sprout only in very young seedlings for a short period of time. After they die and fall off, they are replaced by the plant's permanent stems, or vines.
Towards the end of winter every season, delicate and curling stems begin to sprout from the center of the sea onion bulb. These can get very long and end up growing to lengths of 8 feet (2.5 meters) or longer. As it has a natural tendency to seek a support to climb on, it has also earned the nicknames climbing onion and climbing sea onion. While many people may think that these long tendrils are vines, in reality, they are long flower stems. In the fall, after the plant is done blooming, these stems become very dry, wither, and fall off.
Unfortunately for these flowers, they don't seem to have anything going for them, besides quantity. They're small, plain, and it is said that they have a rather unpleasant odor. Sea onion flowers can not be described as showy. These star-shaped flowers bloom during the spring and summer, and they are often no more than 0.5 inches (1.3 centimeters) across. Dozens of light green or white flowers are produced on each stem every season.
The sea onion requires very little maintenance, and the soil in which it's planted should be left to dry out between watering. It prefers well-drained soil, which can be accomplished by mixing regular potting soil with cactus soil. When the stems begin to dry out at the end of summer, watering should gradually cease and not resume again until new stems start to sprout again.