Planting a Tree in Clay Soil

When getting a new home established or renovating an older yard, planting new trees is an important part of the process. Unfortunately, planting a tree in clay soil does not always yield the desired results. The soil is very difficult to work with in the first place, and then the tree is likely to not grow very well. To avoid this disappointing turn of events, the first step in planting a tree in clay soil is to choose a variety of tree that will tolerate the heavy clay soil.

When planting a tree in clay soil, it is important to consider the pH requirements of the desired species of tree as well as the soil requirements. It is not practical to choose a type of tree that requires soil amendments in order to adjust the pH to fit the tree. This is because trees grow a long time, and their roots spread out over a large area as the tree gets bigger.

Clay Soil pH

Clay soil is often slightly alkaline, with a pH of around 7 to 8.5. It is a good idea to check the pH of your soil before planting a tree in clay soil. This knowledge will help you choose a tree that will be able to grow well in your soil. Some common trees that can thrive in an alkaline clay soil include:

  • elm
  • silver maple
  • aspen
  • cottonwood
  • ginkgo, several types of ash
  • shagbark hickory

If you have an acid soil, planting a tree in clay soil will you require you to choose from a different list of trees. Some that like acid soil and also can thrive in clay soil include balsam fir, red maple, river birch, apple, white pine, Scots pine, and eastern pin oak. Do be sure to check the pH of your soil before choosing your tree species.

Fixing a Hole

Planting a tree in clay soil, once you've chosen your variety of tree, is pretty much the same as planting a tree in any soil. The digging might be a little harder, though. Dig a hole as deep as the root ball and about twice as wide in diameter. The depth should be so that the topmost root is just under the surface of the soil.

To loosen the clay soil you will be putting back into the hole, you can add 1/3 part compost or peat. Don't use all black dirt or compost. Use some of the original soil for the best drainage considerations.

Use the spade to rough up the sides of the hole so it won't harden and make it difficult for the roots to penetrate. When planting a tree in clay soil, it's a good idea to add fertilizer when you are refilling the hole. A good type is a slow release formula with a rating of 10-10-10. This will help to give the tree nutrients throughout the growing season while also keeping the roots from damage.

So, to summarize the preferred methods for planting a tree in clay soil, the most important step is to check the pH and choose a tree that can tolerate clay soil in the pH range your soil is in. Dig the hole and plant the tree, adding a bit of organic soil amendments but not too much.

Add fertilizer, and of course keep the tree watered as it gets established. Following these principles will improve your chances of having a positive experience of growing a tree in your particular type of clay soil.