Understanding Grafting and Graft Collar
Grafting is a widespread method to propagate fruit and
ornamental trees. Grafting allows the tree’s best, such bountiful blooms or
biggest fruit, to be passed on. Mature trees that have undergone this process are
at risk of developing graft collar suckering. For many reasons, this is not desirable.
What is a Graft Collar?
What is a graft collar? A graft collar is the area where a
scion and a rootstock join. It is also referred to as a tree graft union. The
union in a graft is a raised scar that is lumpy and it should be just above the
soil’s surface. It is occurs when the scion and rootstock are united. The scion
is the variety of the tree species that performs/produces the best. The
rootstock is a consistent propagator that the nursery chooses. The reason for
grafting is be sure tree varieties that don’t come from seeds keep the parent
tree’s properties. It is also a faster way to produce a tree compared to
growing a tree from seed.
When grafting occurs, the scion and rootstock grow their
cambium together. The cambium is a living layer of cells found just under the tree’s
bark. This thin layer is joined on the scion and the rootstock. This ensures
that there is an exchange of nutrients and food on both parts. Where the scion
and rootstock heal together is the graft collar.
Should You Bury Graft Unions at Planting?
The location of the tree graft union is important to
consider when planting. A few growers recommend that you bury the union under
the soil. However, the majority recommend that you leave it just above soil –
about 6” -12” above the ground. The union is a rather fragile area and sometimes
improper grafts occur leaving the plant open to rot and disease.