Rudolf in Germany has emailed a guide to its size - 2.4 metres by 1.6 metres or 7' 10" x 5'3.
The tapestry seems to belong to a wider Germanic tradition of Mary being portrayed in a rose garden. Above you can see Stefan Lochner's Virgin in a Rose Bower painted in 1440. The rose was Mary's flower - she was often referred to as the rose without thorn. Two other points of symbolism are manifest here: the infant Jesus holds an apple signifying the holy couple's representation as the new Adam and the new Eve; and around Mary's neck is a medallion bearing a phoenix, symbolizing resurrection and rebirth. It is difficult to determine from this picture whether the rose bower is real, or whether it is an embroidered cloth held up by the angels in each upper corner.
And here is another lovely depiction of The Virgin and Child in a Rose Bower by Martin Schongauer painted in 1473.