Lakemont Grape pruning

'should be pruned severly' - yes, 3 feet is not a massive size for a grape...

why have you planted it in a greenhouse.  I planted mine outside some years ago, it is trained along a perloga some 7m x 2m and would still
get bigger if I left it.  it is always covered with grapes and every winter i
cut all that years growth off.  about thre times during the some i lop it
back with shears and pruners.  it provides lovely dappled shade, grapes for us and the birds.  Mrs Bouquet