Autumn and Winter Splendour: Hong Kong Balsams
Every summer monsoon, the occasional downpours swell the streams, leaving plants on the banks to bear the brunt of torrential damage. As a result, many streamside plants take advantage of the dry autumn and winter season to propagate, and among them is the Hong Kong Balsam (Impatiens hongkongensis) with its large, vibrant yellow blossoms tinged with red! If you're lucky, you get to admire these precious plants during a stroll along the upper reaches of the stream in autumn and winter.
Hong Kong Balsam belongs to the Genus Impatiens, part of a large plant family with over 900 species worldwide, most of which are found in tropical and subtropical regions. China alone is home to over 200 species, including two species native to Hong Kong – Hong Kong Balsam and Chinese Snapweed (Impatiens chinensis).
Quirky Blossoms
The flowers of the Hong Kong Balsam, which bloom from late October to early November, are strikingly large and beautiful, with a delicate yellow hue adorned by crimson or purplish-red speckles in the centre. The flowers also have a unique shape, resembling a bell, but with an elongated and gracefully curved "tail" at the end. This is an extension of the calyx, also known as the "spur", which holds nectar at its tip.
The lower part of the flowers has two large petals that serve as landing platforms for nectar-gathering insects. The crimson or purplish-red speckles in the centre serve as markers that show the insects just the right place to touch down. This consideration is, of course, intended to allow visiting insects to pollinate these flowers even more effectively! However, the Hong Kong Balsam does not welcome all insects. Since the nectar is at the tip of the spur, only insects with elongated proboscises, such as moths and butterflies, can penetrate deeply to sip the nectar and facilitate pollination.
Ready to Pop
The fruits of the Hong Kong Balsam have a rather fascinating way of dispersing their seeds. The fruits have the shape of capsules. When they are ripe, a gentle touch is enough for the pericarp to burst open and the seeds to be widely dispersed. This earned the Hong Kong Balsam the nickname "Touch-me-not". Its Latin genus name, Impatiens, meaning "impatient", describes this "explosive" way of seed dispersal as aptly as it does vividly!
The Hong Kong Balsam was first discovered globally in 1925 in Tai Po, Hong Kong. It was officially named and classified as a new species in 1979, and bears the name of Hong Kong. Currently, it is recorded only in Hong Kong and Shenzhen. It grows exclusively in pristine wilderness, along the banks of streams and rivers at elevations of 150 to 210 metres, or in damp areas near valley waterfalls. Being exceptionally rare and precious, it is listed in the "Rare and Precious Plants of Hong Kong" and is protected under the Forestry Regulations (Cap. 96 sub. leg. of Laws of Hong Kong).