Linen is made from flax plant fibres. When undyed, it is fully biodegradable. The flax plant is very resilient and grows easily without pesticides. It also needs far less water than cotton. To give you an idea, across its lifecycle, a linen shirt uses 6.4 litres of water vs. 2700L for a cotton shirt.
Our flax plants were grown in France and Belgium. The linen is treated with a gentle fluoride-free water repellent.