Yareta is well-adapted to high insolation rates which are typical of the highlands, and cannot grow in shade.
The plant grows in a very compact way in order to reduce heat losses and very close to ground level where air temperature is one or two degrees Celsius higher than the mean air temperature.
It is so compact in fact that locals have for many years collected yareta (with pickaxes) to use as fuel for cooking.
The plant grows at a rate of approximately one millimeter per year, and thus many yaretas are over 3,000 years old."
info from various sources (mainly wikipedia)