I have very compacted rocky clay soil where I want to plant some trees and shrubs. It is nearly impossible to dig. Can I build a raised bed to raise the soil level and plant the tree in the raised bed?
Can anyone direct me to instructions for planting trees on mounds or raised beds?
Yes, you can build raised beds for your trees and shrubs, but if your soil is as bad as you claim, your raised beds will need to be 3 to 4 feet tall to accomodate tree roots...maybe even bigger depending on what kind of trees you want to plant.
Tree roots can go pretty deep, so can some shrubs. A raised bed one foot tall isn't going to help you much, as any roots will eventually hit your native soil and have nowhere to go except "out", not down.
Making a raised bed, and then adding a different type of soil to it is creating a layer...which can lead to problems like root rot, etc. since the native soil underneath is clay and probably doesn't drain well.
You would need to integrate the two types of soil instead of piling one on top of the other, by rototilling or some other mechanical means.
Have you tried breaking through the native soil and really ammending it? This can be labor intensive, but possible.
Sometimes you can break through the clay layer and hit a different type of soil beneath it which may be more hospitable to growing.
If you can dig deep enough through the rocky clay and incorporate a lot of organic matter, it will eventually work it's way down deeper, but you have to do the inital breaking- through first.
This is a difficult question to answer without actually being able to see the type of soil you have.
I think I will get out the grubbing hoe and pick and get as deep as possible--guess I was looking for an easier way. There are plenty of native trees and shrubs as well as ones we've planted, but this area was graded down to the subsoil & I've added enough top soil for grass, but not enough for trees. I appreciate your help.