Hello Jennifer, Three years ago on one of our projects we planted 2-120″ box Q- agrifolias 1-84″ quercus agrifolia 1-72″ box and about 15-20 60″ box trees. (all are thriving) The 120″ and 84″ were field grown the 72″& 60″ were box grown. Because this project underwent quite a bit of grading and recompaction we made sure all of the trees had subdrains. 4″ diameter perforated pipe with sweep ells in 1′ of 3/4″ crushed rock. (Or 4″ perforated drain with filter sock and coarse sand backfill.) Fortunately the site has quite a bit of fall so we were able to get these subdrains to daylight to our v gutter system. This drain is set below the bottom of the rootball. (in a 1′ trench at the bottom of the pit.) We also try to dig the pit so water would drain to this trench.) This prevents excessive water from collecting in the bottom of the planting pit after irrigation. (Which can be like a bathtub if the soil is compacted to 95% Proctor.) The other thing we do is limit any organic amendments to the top 18″ of soil. (Everything below that is just site soil.) This prevents organic matter from putrefying under anaerobic conditions at the bottom the planting pit. (which could cause root rot) Fortunately we had a Sandy loam type site soil. Because the root ball was so large on the 120’s (and the trees fairly broad) we did not guy the trees in any way. But if i were to do so i might cable it to some sort of concrete deadman in the bottom of the pit to prevent it from overturning. (some people use pressure treated 6×6 timbers but i would go with something that wouldnt rot and isn’t impregnated with copper / chemicals. Its a good idea to have the arborist go out and look at the tree before delivery. (It may have rooted into the ground and could shock when when they they move it to the truck.)(typically symptoms probably wouldnt show up for a couple weeks) We use a very good tree broker who is good at identifying such problems. BTW They are usually very resilient trees! Hope that helps!?
