Do reed-beds require a lot of maintenance?

No, but regular maintenance is essential.  Most reed-bed maintenace is simple and can be carried out by anyone with a modicum of gardening experience. 

Mostly it consists of weeding especially in the first few years. 

We reommend that in addition the reeds are cut annually after the second year’s growth and all the dead plant material is removed completely from the surface of the bed, whether vertical flow or horizontal flow.