Planting Trees and Shrubs Correctly
Unfortunately, many trees and shrubs fail because they were not planted correctly. For plants that die in the first 1 to 2 seasons, planting technique and aftercare are usually to blame. Planting and establishing trees is all about providing adequate conditions for root growth – this means managing air and water in the soil. Manage these conditions correctly, and trees will grow quickly. Fail to manage them, and your trees will fail.
Four of the most common causes of poor plant establishment are:
- Planting too deeply
- Under watering
- Over watering
- Over mulching
Each of these problems can lead to poor growth, slow decline or tree death. If appropriate trees are planted at the right depth and irrigated properly, the planting has a good chance of success.
Before digging your hole, find the point where the top-most root emerges from the trunk (dig down next to the trunk to find this point) and measure the distance between the top-most root and the bottom of the root ball. Dig the hole slightly shallower than this depth and as wide a possible (at least 1.5 times the width of the ball but preferable 3 times the width of the ball in compacted soils). Do not dig the hole deeper than the root ball. This ensures that the point where the top-most root emerges from the trunk remains at or slightly above ground even if the root ball settles.
Fill the planting hole back in with the soil that you removed from the hole. (If you need to amend your soil, amend an entire planting bed at a time and till the amendments into the top 6-8 inches of the soil profile prior to digging your holes. Do not add amendments to the planting hole itself.) Use the blade of your shovel or water to gently settle the soil in the hole and remove air pockets. Don’t stomp with your feet, a shovel handle or any other implement that will compact the soil. Soil should cover the sides of the root ball but do not pull soil over the top of the root ball. This impedes the movement of air and water in to the root ball.
Planting too deeply can cause several problems. First, it reduces air exchange between soil and air. The result can be roots starved for oxygen. Planting deeply can trap too much moisture in the root ball, especially if the soil is poorly drained. Deep planting can also lead to the root ball drying out. This occurs because the soil and mulch placed over the root ball holds some of the water applied over the root ball. Finally, deep planting also can encourage development of stem-girdling roots that can kill trees. These roots develop because the loose soil spread over the root ball is very suitable for root growth.
Form a water ring (berm) from mulch only if trees will be irrigated with a hose. The water ring is not needed if trees will not be watered after planting or if trees are irrigated with a drip hose, drip irrigation system or tree gator. Water rings made from soil can lead to problems because the soil is typically pushed over the root ball later. If you opt to make the berm out of soil, make sure you rake it down after the first season that the plant is in the ground and distribute the soil away from the tree’s roots. Roots will grow extremely fast into the mulch and surrounding soil and trees establish quickly using this planting technique.
Apply your mulch. Do not use a landscape fabric (which does not eliminate or exclude weeds but can inhibit the movement of water and organic matter into the soil below) and do use an organic mulch such as wood chips, pine bark nuggets or pine straw. Apply no more than 4 inches of mulch and keep it 12 to 18 inches away from the trunk of the tree. Too much mulch applied over the root ball or resting against the trunk can cause problems for trees. The roots often grow up into the mulch causing stem girdling roots that can kill trees. Water weekly through the first season if you do not receive one inch of rain during the week.