The stunning jade vine (Strongylodon macrobotrys; family Fabaceae) in Selby Gardens’ Tropical Conservatory is developing a seed pod for the first time. The reason, greenhouse horticulturist Addie Worth provided pollination assistance! Without some help, jade vines cannot produce fruits in cultivation since its pollinator is a bat and they are not usually allowed into the Conservatory. In nature and hanging upside down, a bat will force its way into the flower to get at the nectar, causing the cats-claw-like petals to bend up and extrude pollen onto the back of the bat’s head. That pollen is then carried to the next flower and hopefully for the plant, makes contact with the stigma. The stigma is the female part of the flower that receives the pollen; the pollen then germinates and grows down through the slender style to the ovary. If it, and other pollen grains, have a successful journey, the ovary will develop into a full fruit. In this case, the fruit is a baseball-sized, slightly elongated, and flattened pod with 4-6 seeds.
The remarkable flower color is the result of co-pigmentation, an interaction between anthocyanins, which can bring anything from pink to blue depending on soil pH, similar to hydrangeas, and a flavonoid, adding a yellow coloration. Under the right pH conditions this combination results in the green-blue jade or turquoise coloration that is most unusual in the plant kingdom.
The jade vine, actually a liana (woody vine), can grow 50-60 ft. (15-18 m) in length and is considered threatened in the wild by some as its forest habitat in the Philippines is being impacted by logging. Fortunately the species is now being grown around the world and protected to some extent in botanical gardens.
Our particular jade vine was donated by long-time volunteer, Anne Madden, who obtained it from a local nursery and was planted in 2013. Since then, according to Angel Lara, Director of Glasshouse Collections, the vine has reliably bloomed every year around St. Patrick’s Day. We hope to share photographs of the seeds when the fruit is mature.
Watch a short video from the Eden Project that shows how the pollen is ingeniously extruded: https://www.edenproject.com/learn/for-everyone/plant-profiles/jade-vine