Things to Avoid when Planting Trees
There a number of situations that can arise during planting that can be detrimental to the health of a new tree seedling. Sometimes seedlings planted the wrong way will begin to die as soon after they are planted but other times problems may not show until the plant is well established and it’s too late. An otherwise healthily growing tree can suddenly lose vigour and die leaving the person who planted it to only wonder why. Often disease will be blamed for the death of a tree when actually it was the technique used during planting that was to blame.
The following is a list of some things to avoid when planting tree seedlings, although most of the tips given here also apply when planting out any type of plant.
Avoid Crushing the Leader and Branches of the Tree
The best way to get a plant out of a tube-stock or pot while avoiding damaging the leader or branches is to give the rim of the pot a firm tap with a small mallet or other improvised object. The soil around the edges of the pot should loosen up and the plant should then slide out easily if this has been done correctly.
If severely root bound it’s better to cut open the bottom of the pot or tube and damage some of the lower roots in the process than to tug at the plant and possibly damage the leader of the tree.
Trees are unable to repair damaged tissues in the way that animals can, instead they just form calluses around damaged areas to seal them off from pathogens and insect pests. Damaged areas are no longer able to transport nutrients and water to and from growing areas above the damaged point.
If the leader of the tree is damaged but the seedling survives and continues to grow this may cause the trunk of the tree when older to be weaker, more prone to infection by pathogens or pests, and more likely to fall over during heavy winds. Likewise damaged branches will be more prone to snapping and falling off. Unfortunately this can result in property damage, as well as potentially injure people and even cause loss of life.
Avoid Creating J-Roots
J-roots occur when the seedling is planted in such a way that the lower roots of the plant bend upwards towards the surface of the soil. When a tree is planted this way the roots are less able to spread out evenly and will tend to be concentrated in the upper layer of soil making them more prone to drying out. Some roots will even grow upwards, become exposed to air and die-back.
While tree seedlings planted this way may still grow in areas with good rainfall or if watered regularly, even the shortest period of drought will easily kill it as the shallow root system of the tree will dry out quickly. J-rooted seedlings are also less able to extract nutrients from deep within the soil and as a result are more likely to grow slower and have nutrient deficiencies.
J-Roots are more likely to occur when planting into a hole that isn’t deep enough to hold the full length of the root ball or when the walls of the planting hole or debris such as other tree roots or rocks catch on the root ball and bend it upwards during planting. To prevent J-roots be sure that the roots of the tree seedling go straight down and are not bent before refilling a hold with backfill.
Avoid Planting Seedlings that are Rootbound or have Tangled Roots
When a tree seedling has been left too long before planting, the roots will begin to wrap around the sides and base of the container they are grown in multiple times. If rootbound plants are planted without freeing the roots first they may grow reasonably well for several years but eventually as the roots thicken they will being to strangle each other as well as the lower trunk of the tree, eventually stopping all water and nutrient flow and killing the tree.
While it’s best to plant out plants before they become rootbound, if they’ve been left too long but you still want to plant them you should slice down the side of the root ball about four times (once for each side if planting out a square tube-stock). Create a small mound at the bottom of the planting hole and spread the 4 sections of roots out eventually over the mound. Any severed roots will quickly rot away and new non-tangled roots will grow back in their place which will be able to spread out into the surrounding soil.
Avoid Creating Air Pockets in the Soil around the Tree Roots
When roots grow into air pockets in the soil they will die as there is not enough moisture around the roots to sustain them. This is similar to what happen when roots come out of the bottom of a pot which is termed as air-pruning in the horticultural trade.
To avoid creating air pockets you should ensure that you backfill evenly around and under the roots of the seedling. Break up any large clumps of soil while backfilling otherwise they will not fit snugly with other clumps and create air pockets, large clods of clay can be especially problematic in this regard. The soil should firmed down eventually around the seedling with your hands to further reduce air pocketing but avoid compacting the soil too much as this will inhibit root growth.
Avoid Planting Tree Seedlings too Shallow or Deep
It’s best to plant out seedlings at about the same level as they’re growing at in their pot. Don’t cover the top of the root ball with extra soil when planting or the seedling will end up too deep in the ground.
Tree seedlings planted too deeply are prone to rotting as part of the trunk of the tree will be surrounded by damp soil. If some of the potting mix from the top of the root ball falls away when planting be sure to plant the seedling deeper and replace the lost mix with soil backfill. Seedlings planted too shallowly are more likely to dry out and be more unstable and prone to falling over in strong winds as their roots will be too close too the surface to provide sufficient anchorage for the growing tree.
Avoid Planting Tree Seedlings over the Top of Large Rocks
While it’s true that most tree roots to not extend as deeply in the soil as traditionally thought and instead are more likely to spread out laterally closer to the surface, the roots still need sufficient soil depth to reach their full, adult width which can be quite thick in some species.
If there are rocks in the way one side of the root may become compressed as it grows and be less effective at transporting nutrients and water to the growing branches above, in severe cases this can result in the death of these branches. Try to instead plant native groundcovers and shrubs with shallower root systems if planting into an area with rocky, shallow soils.
Most trees will fail to thrive when planted on shallow soils, although there are some species (especially alpine species which grow on the sides of mountains) which may tolerate shallower soils.