Japan’s Fantastic Emerald Green Algae

Japan’s fantastic emerald green algaeThink of Japanese gardens and candyfloss clouds of cherry blossom, canopies of bronze-leaved maples and arched red lacquer bridges might come to mind. Yet to me the understated beauty of Japanese horticulture goes far beyond this random collection of individual elements that are really just a handful of Western preconceptions.

Rather than relying on a riotous blaze of colour that underpins so much of European horticulture, from bedding displays to herbaceous borders, Japanese garden style embraces the subtleties of structure, texture and form to a far greater extent to provide visual interest.

This radically different philosophy has created an approach to horticulture that can sometimes do things which are barely comprehensible to Western gardeners, with schemes highlighting the overlooked beauty of mosses, weeds, even algae as their central point of interest. Yes, algae.

Marimo Aegagropila linnaei (literally meaning “ball seaweed” in Japanese) are furry, emerald green algae that naturally group together to from dense, soft balls of verdant fuzz. They are found across the world’s temperate lakes from Iceland and Scotland to Australia, but it is only in Japan where their cultivation has reached cult status.

It is only in Japan where ball seaweed cultivation has reached cult status
Sacred to the indigenous Ainu people of Hokkaido, they are popped into mini aquariums, glass jars and even into tiny water-filled amulets worn as jewellery. They are one of the most quirky, low-maintenance houseplants around. In Britain these slow-growing, velvety spheres can be picked up both in aquarium shops and on internet auction sites for the same price as far more boring offerings, usually sold as “Japanese moss” or “moss balls”.

Teamed up with pebbles and sometimes even driftwood, marimo are used to create naturalistic, underwater landscapes in miniature – like a sort of hybrid between aquariums, bonsai and terrariums.

Last summer I gave them a go. I filled a two-litre Kilner jar with water, popping in a few pebbles and a collection of marimo balls of different sizes. The professionals say only softened, dechlorinated water should be used. But I just filled my little jar with hard London tap water and left it in a bright corner of my living room away from direct sunlight and waited to see what would happen.

Six months later I have still done pretty much nothing to it, apart from topping up the water when it evaporates off every month or so, and it looks as perfect as the day I made it. The living marimo, to my surprise, keep the water crystal clear and free of any nasty regular algae, creating a stunning miniature, self-sustaining aquascape for essentially zero effort and for the price of a bunch of flowers. I love it.