In my blog last week on planting a potted tree, explaining root pruning prior to planting, I promised that the next blog would cover the width of the hole.
Dig wide holes – no deeper than the height of the root ball of the tree, shrub or perennial you are placing in your landscape. How wide you should dig depends on the condition of the soil at the planting site.
If the soil is loose, crumbly uncompacted soil that digs every easily, a hole just a few inches -6″-12″ wider than the root ball will do just fine. In soils like this, new roots can extend very quickly into the surrounding soil.
If the planting soil has hard, compacted soil that is really difficult to dig into, you should dig a very wide hole that is several times the width of the root ball. Or a #7 potted tree or shrubs that is 13″ wide, a hole about 2 1/2′–3′ wide would be excellent. Remember – no deeper than the height of the root ball.
For a balled and burlapped tree that has a wire basket and burlap ball of 24″-36″ in diameter, holes of 4′ to 6′ wide, or even wider are best when planting in compacted soil. This allows for rapid root extension and establishment of the plant.
The unfortunate thing about the advice I am giving is that it calls for making the biggest hole in the worst possible digging conditions. If you have badly compacted soil it may be a good idea to use power equipment to dig the holes. Big augers, backhoes and u-blades are most commonly used to make extra wide holes in hard soils.
The extra effort is worth it, resulting in far better plant growth. Every plant on the planet loves growing in nice loose uncompacted soil. When they have this situation, the plants can reveal their full genetic potential.