Wisteria thrive on neglect and poor soil. Would you know what variety you have (Chinese, Japanese or American?). They are all very similar looking but not actually the same species. They all tend to have a tap root and shallow feeding roots. They will all do well next a building if the soil drains well. In the UK south or west facing is best, but they will also do OK in east facing but poorly in north facing.

It's a wisteria prolifica sinencis if I remember rightly and I have planted it on an east facing wall. Is it right that they do not need deep soil to thrive, I have also mulched mine well, do they need much water, not that we have a lack of rain at the moment.

Chinese Wisteria - actually a member of the Pea family! East facing wall is OK, they will flower better in south facing but as long as it is not over shadowed and get the maximum amount of sun available then it should be fine. The roots are shallow so no need to dig too deep but it is good to loosen the soil if compacted. They do need water in summer and the mulch sounds great.

It needs full sun and good draining soil. If you are not getting blooms it usually means you have too much nitrogen in the soil, you need to add phosphorous (phosphate fertilizer) which wisteria need to produce blooms. Also if you fertilize incorrectly you will not get blooms, you need to fertilize wisteria in the fall if you do it in the spring it will encourage leaf growth but discourage blooms. So check your soil and see if it is high in nitrogen if so add phosphorus.