A year ago I came across a mention of Marimo somewhere on the net. I had forgotten about them until a couple of weeks ago I found myself in an aquarium store and saw some in a fish tank. Since this was a serious kind of aquarium shop they were labeled "Japanese moss balls" but I recognized it right away as a "Marimo." Being one of those suckers born every minute I had to have one if only for the plant geek points. Lately I've been sort of uninspired with collection of indoor plants and have had the strangest urge to grow mosses and ferns. Which is partly responsible for the lack of updates here. I don't know why but lately but plants that are little more than boring green mounds have seemed like something I want to grow.
Anyway, this is my Marimo that I have named Maximus and here he is in a jar of water taking in some morning sun while browsing some garden blogs. Since he doesn't have hands he can't comment but he enjoys reading them. Marimos are actually a fresh water algae (Cladophora aegagropila) and information on them on the internet has to be gleaned from reading from various sources. Fish tank nerds seem to be at the forefront in the U.S.
Domestic Marimo can be grown in tap water at room temperature and be given small amounts of liquid fertilizer with half water changes on a weekly basis. The amount of light it needs varies from source to source. Some places say this plant needs high light while others say it requires little more than ambient light.
They're native to Japan and Russia and supposedly Iowa, of all places. They develop their characteristically round shape because water currents push them around the bottom of lake beds. This Marimo is more of an egg shape because it was growing in a colony pressed up against a corner of the plant tank at the aquarium shop I bought it at.
They "reproduce" when a bump forms on a Marimo and it falls off and gets pushed around until it forms the round shape. If you don't want to wait for that you can tear it apart. You can clean your Marimo by dipping it in water and gently squeezing like you would a dirty sponge.
From my lurking at fish tank forums I've gathered that you can find fake Marimos in a lot of places, PETCO being the biggest seller of them. If you buy a Marimo that floats around your fish tank chances are that you've purchased Java Moss wrapped in a ping pong ball.
Maximus looks a little sorry growing in a jar so I may use him as an excuse to purchase a small aquarium to grow him and other aquatic plants and maybe a fish.