By Edburke
Virginia,
United States 
I'm planting a wisteria into ground that is solid clay and is sometimes waterlogged for long periods. I added amendments to the clay down to one foot. Now I want to add a raised bed over it (3' x 3' 1' high). Two questions: Am I not allowing the roots enough lateral space to grow with my 3' by 3' raised enclosure. 2) When the roots grow below the two feet of amended soil into the wet clay, I wonder whether it will kill or otherwise affect the vine, since I believe wisteria do not like wet feet. Many thanks. Ed Burke
On plant
30-footy vine originating in Oklahoma
14 Aug, 2018
Why is the clay so wet, Ed? Is it an area near a stream or bog where the water table is high? Or is it just a low area in the garden where all the rain drains to? What is the soil pH? In acid soil--pH below 6.5--you can add limestone, which will gradually open up the clay and help it to drain better. In neutral to alkaline soil--pH above 6.5--gypsum works better than lime. Both work a bit slowly, so I would put them in a year before planting the Wisteria.
15 Aug, 2018