can anyone tell me why my wisteria tree has died

I`m sorry i can`t answer your question but I have had exactly the same problem. My Wisteria is 4 years old and has flowered beautifully every year, I thought it would do the same this year as it was covered in buds, but it has just stopped like that. I also have new shoots at the bottom and since I sprayed it with soapy water a few leaves are trying to grow higher up. I have read an article about an asian beetle that has been in the country since 2001 that attacks wisteria and maybe other flowering plants. I have found 1 or 2 brown scale insects on it but not enough to cause such a huge problem. It`s a puzzle. I have a cutting off the same plant that i have grown as a standard tree and it is flowering like crazy and looks healthy, I have sprayed soapy water on it as a precaution. The article i read is on the Telegraph web page under "Wisteria Murderer". Good Luck