Scion rooting is a leading cause of variability through the block.
Scion roots will negate any effect/benefit from the rootstock. This results in an excessively vigorous tree (figure 1) that becomes unmanageable and in time highly unprofitable. Once the scion roots take hold it’s extremely difficult to control the tree with the only viable option left is to remove the tree.
This can all be avoided at planting time. Ensuring the trees are planted at the correct depth. Rigorous quality checks during the planting process will pay dividends.
It’s critical your planting team can identify the graft union, especially if your trees are bench grafted. The bud &/or the bench graft union must be 100-150 mm above the soil surface after the tree has been healed in (Fig 2 & 3). Remember the tree does settle down after being planting, so this must be allowed for.
Dean Rainham,
Agfirst Horticultural Consultant
