A few of the traits often associated with those who lived during the Victorian era were prudish behavior, a strange obsession with the occult and an attraction to alluring plants that hailed from exotic locations.
It was the era of taxonomic exploration that allowed the masses to fill their houses with species that occurred in both the New and Old World tropics. Undoubtedly some were fueled by adventure, or a sense of duty. However, it is hard not to think that the botanists of the time were simply just captivated by the beauty of these species, previously unknown to science.
In this month’s column, we showcase the uniquely colored jades vines, which are a group of lianas in the Fabaceae family (aka the bean family). This family includes everything from peanuts to wiliwili (a species of flowering tree). Jade vines can have either orangish-red or bluish-green flowers and all species show potential for garden plants. There are 15 to 20 species of jade vine, or Strongylodon, currently known to botanists.
They are native to an area that spans from Madagascar to Polynesia. The largest concentration of species can be found in the Philippines.
However, Hawaii residents generally see Strongylodon macrobotrys with its strikingly uncommon, pendulous clumps of jade- to turquoise-colored flowers. The unusual color of the species’ flowers attract an uncommon pollinator.
Around 530 plant species rely on bats as pollinators. Many of these, like cacti and succulents occur in arid regions. However, there are several found in tropical rainforests to include S. macrobotrys. The luminous quality of the flowers is thought to attract bats, who then hang upside down on the flowers to enjoy a nectar reward. While the bat drinks, pollen is brushed onto its head. If a flower is successfully pollinated, it will develop into a large legume. Members of this genus that have orangish-red flowers, like the native nuku ‘i‘iwi (S. ruber), are typically pollinated by birds. This species was most likely pollinated by one of Hawaii’s endangered, endemic honeycreepers. Curiously enough the Hawaiian name refers to the flower’s resemblance to an ‘i‘iwi’s bill. Due to the rarity of this species it is seldom seen in the private, or public gardens of Hawaii, despite the effort of many propagators.
The nonnative S. macrobotrys is occasionally cultivated in gardens across the islands. One challenge to growing this vine is building a trellis that is strong enough to support it. Remember the plant is a woody vine, or liana, and will get very heavy as it matures. Regular removal of dead leaves and pruning can help to reduce the weight, and wear and tear on your trellis.
Training this vine up a trellis or tree will keep it at the proper height, ideally
6 to 10 feet above ground, to display the flower clusters. To maximize the number of flower clusters, make sure that as much of the stem as possible is parallel to the ground. These blossoms can be used for decoration and lei, and are produced February through May. Caution: The flowers will stain your clothing, so take care in picking out your outfit or when giving it as a gift.
This plant requires a sheltered area with full sun and organically rich, moist soil. They can be vegetatively propagated through air layers or cuttings, but survival rates are often low. Growing them from seed can also be tricky since they rarely produce seeds in cultivation.
Many garden shops ephemerally stock this plant, so keep your eye out for it. Jade vine has a low risk of them becoming invasive based on the Hawai‘i Pacific Weed Risk Assessment. Also, by planting one of these vines you also aid in its conservation. This species, like our native one, is becoming rarer due to habitat loss, which is occurring at an alarming rate.
Jesse Adams and Tim Kroessig are both botanists at the Harold L. Lyon Arboretum, where they work to catalogue, propagate and conserve the plant diversity found there.
