The garlic vine is a woody, flowering climber that is often featured in tropical garden books. A member of the Bignoniaceae family, known via a range of synonymous botanical names but best referred to as Mansoa hymenaea. This flowering vine is native to tropical South America, from Mexico to Brazil. In Costa Rica, it can be found growing from sea level to 900 m in elevation. Interestingly, it is not related to the common edible onion or garlic at all!
In its native habitat, it is said that the garlic vine attaches itself around the trunk of a large tree for support as it climbs skywards to reach for sunlight. The terminal leaflet of this plant is often modified into a tendril that helps the vine to cling onto a support. Because of its large size, it is only practical to grow the garlic vine in outdoor gardens with a trellis. It is a vine with a moderate growth rate and one need not worry that is will become an unruly resident in the garden.
The garlic vine is well known for its leaves that emit a garlicky smell only when crushed. Its blossoms also give off a faint garlic odour but one need not worry about the garden smelling like the kitchen spice when in flower. Because of this characteristic, it is not surprising that the plant can be used as a substitute for garlic in the kitchen. The entire plant such as roots, stems and leaves have medicinal uses and are used to reduce fevers, treat colds, throat, and respiratory troubles.
The plant is a climbing vine that turns woody and heavy over time. Hence it is recommended to grow it on a strong timber trellis in an exposed area where it can receive direct sunshine for most of the day. It is best to grow it in well-drained soil that is mulched at the base with compost to keep the roots cool and moist. Keep it well-watered so that plants do not shed its lower leaves which can make vines look straggly.
Like many other flowering vines, the garlic vine should not be overly pruned as flower buds appear on new growth. Many gardeners make this mistake by pruning away the vines to keep new growth in check and as a result, plants refuse to produce flowers. Semi-hardwood cuttings can be taken for propagation. Each stem should have at least 3 nodes and can be stuck into a mixture of sand and compost to start the rooting process, after removing some leaves to reduce water loss. Rooting hormone powder is usually not needed.
This vine is not a constant bloomer. It occasionally produces flowers here in Singapore and whenever it decides to do so, the flowering is often described as profuse. The entire vine can be covered with flowers. Flowers are trumpet-shaped and produced in dense clusters. Each starts off purple and changes to a lighter shade of lavender with age and finally fading to white before it turns brown and drops off from the vine. At any one time, one can see three different floral colours on the plant.