Absolutely. I used to use old sheets of plastic. The type used in estate agent for sale signs, although election posters are a better size. Easily cut to wedge inside the wheel arches. I put a brick on the ground to keep the bottom snug to the wheel, although you could punch holes to allow for string or elastic securing.
I also recommend ‘foreverblack’ tyre gel which I apply to the sidewalls with a paintbrush every few months. Being doing it for about six or seven years.
http://www.motorgeek.co.uk/cgi…db_pid=122
A proper dye which shields the tyre from UV and contains molecular replacements similar to those within the tyre which become degraded as tyres age. This accelerates if the tyre is not in regular use. Anti UV molecules are mixed into the tyre at manufacture (making the tyres black) these are pumped to the outer surface of the tyre as it turns during Its use. The molecules are sacrificed to protect the rubber of the tyres. When the wheel sits unused (especially in sunlight) the molecules eventually degrade and leave the sidewalls a grey colour. The rubber hardens and then the cracks begin to appear.
Either cover as Ally suggests or paint as I do. These simple acts save you a considerable amount of money in keeping your tyres in good order and as we all know blow outs generally are sidewall failures.
Davy