No
Phragmites is a very common reed and people have always used them for various things (thatching roofs, etc.) What knights have to do with this I really do not know!
Phragmites were used to thatch roofs and to weave baskets and such things. They did not grow everywhere, but where they did grow, serfs probably used them.
Phragmites are also known as "Common Reed."
yes
Phragmites are eaten by both Algae and destroyed by Chemichal Changes in it's nucleus
Phragmites can be found in swamps and marshes throughout temperate and tropical regions of the world.
No.
The barracks of a castle are the homes of the knights and their families.
The genus Phragmites are tropical reeds (tall grasses), the most common of which has become an invasive species in some tropical and semi-tropical biomes (Phragmites australis).
No.
The cloud district
Knights often lived in their own mansions or homes on the land they owned, when they weren't lodging with their king or superior lord.