Leiden University: Rare jade vine flowers in Hortus botanicus in Leiden

The jade vine (Strongylodon macrobotrys) is flowering at the Hortus botanicus in Leiden. The plant started producing multiple flower clusters three weeks ago and the first ones are now in full bloom.

This is the first time in three years that several clusters have flowered at once. The striking blue-green colour makes the plant unique in the plant kingdom. The jade vine is a climbing plant from the Philippines that is rarely found in the wild anymore.

The plant can be seen on the second floor of the tropical greenhouse, where it has been growing and flowering for almost 30 years. It was pruned in 2019 and in the three years since has failed to produce several clusters at a time. Only one cluster bloomed in 2020.

Why the flowers are a special blue-green colour is a mystery in the botanical world. It is known that bats pollinate the flowers in the wild. One theory is that the blue colour makes the flowers extra visible to bats at night, but bats mainly use sonar waves to explore their surroundings, which makes this theory unlikely.

Collection
The specimen in the Hortus greenhouse was raised from seed in 1996 by former greenhouse manager Art Vogel. The seed came from a plant that a friend of Vogel’s had collected from the wild near Mount Makiling on the island of Luzon in the Philippines.

When Vogel visited his friend in West Malaysia, he was so impressed with the plant that he wanted to add it to the collection at the Hortus. He was given permission to collect a seed capsule from the plant and germinated the seeds in the Hortus when he returned from his trip in January 1996.