Yes, it would be good to at least prepare/amend the soil at and near the planting sites. Trees usually appreciate a healthy, somewhat loose (non-compacted), well-draining soil, especially around the root ball. It’s best to first test your soil to see what the pH is and the kind of amendments/fertilizers that are needed (the link that Anne has listed in her reply gives you some details on that). Also, it is important to amend a clay soil to improve drainage, and to remove the rocks in the planting hole. Moisture-tolerant tree species may do better in heavy clay.
The depth of a tree planting hole for heavy clay should be two to three times as wide as the diameter of the root ball, and about the same depth as the root ball. (If you can not improve drainage, then the depth should be about 2 to 3 inches shallower than the rootball, so that water can drain away from the trunk.) Loosen the soil at the planting site and remove any rocks as best you can. Tree roots will, of course, grow beyond the root ball area, so loosening the soil beyond this area is beneficial to root growth. To improve soil structure, add one part coarse organic materials (such as compost; do not use fresh manure or commercial fertilizers, which will burn roots) to one to two parts soil in and around the planting area.
Hi, Regina,
Yes, it would be good to at least prepare/amend the soil at and near the planting sites. Trees usually appreciate a healthy, somewhat loose (non-compacted), well-draining soil, especially around the root ball. It’s best to first test your soil to see what the pH is and the kind of amendments/fertilizers that are needed (the link that Anne has listed in her reply gives you some details on that). Also, it is important to amend a clay soil to improve drainage, and to remove the rocks in the planting hole. Moisture-tolerant tree species may do better in heavy clay.
The depth of a tree planting hole for heavy clay should be two to three times as wide as the diameter of the root ball, and about the same depth as the root ball. (If you can not improve drainage, then the depth should be about 2 to 3 inches shallower than the rootball, so that water can drain away from the trunk.) Loosen the soil at the planting site and remove any rocks as best you can. Tree roots will, of course, grow beyond the root ball area, so loosening the soil beyond this area is beneficial to root growth. To improve soil structure, add one part coarse organic materials (such as compost; do not use fresh manure or commercial fertilizers, which will burn roots) to one to two parts soil in and around the planting area.
Hope this helps!