Planting trees & shrubs in clay
- Dig a hole at least twice the diameter of the root ball, but no deeper than its height. Rough up the sides to make it easier for roots to penetrate. Don’t add gravel to the bottom in hopes of improving drainage. According to research done at the University of Minnesota, a layer of gravel creates a perched water table that causes the soil above the gravel to hold even more water.
- Position the root ball in the hole, ensuring that it sits at or slightly above grade; plants that settle below grade can suffer from root rot.
- Backfill with the soil you removed (if it’s relatively fertile) or amend it slightly by adding organic matter. If you amend the backfill material too radically, the resulting drastic change in soil fertility and texture will discourage roots from spreading out beyond the sides of the hole. It’s best to heavily amend the whole bed or border than individual planting areas wherever possible, but it’s better to amend a single planting hole than do nothing at all.