It is the time of the year when many operations plant potted almond trees. Although potted trees are convenient with the year round availability and planting time (almost any month if properly irrigated), there are a few considerations at planting that must be considered in order to prevent root girdling and future orchard loss.
Root girdling of trees occurs when roots grow in odd directions. These roots wrap over or around other roots or the trunk, eventually preventing the flow of water and nutrients while limiting structural integrity. The problem is usually not noticeable at first, but 6-8 months after planting, the trees begin to show reduced growth. Later, these trees often become victim of wet feet or Phytophthora due to over-irrigation of the tree. Over-irrigation occurs from to the inability to pull water at the same rate due to the constricted xylem and reduced canopy size in comparison to healthy trees. In cases in which the trees survive and are kept through the third leaf, they may snap off at ground level from the shaking process. The issue seems to be more severe with more vigorous rootstocks.
Root girdling is often caused by root kinks. Root kinks occur due to the misdirected growth of roots as they become pot-bound. It is not uncommon to see tree roots growing up or around when left in a pot too long. Some modern pot technology may help reduce the occurrence, but any tree, if kept to long, would have excessive root kinks.
Root girdling can be prevented by planting trees that do not have observed root kinks. Trees should be examined prior to planting. If the trees have lignified roots (woody roots) which are growing in multiple directions, it is important to return the plants or break the root ball up in attempts to redirect growth (New roots grow outwards from the damaged areas). This tends to be older plants. Some might argue that this ruins the whole point of a potted plant, but at least it will live longer than 3 years. Trees should be planted properly. The young roots should not be shoved into the planting hole as this may bend roots upwards, creating a “J-root.”