We were left with several citrus trees which had reverted back to their root stock, which is the sour orange (Νεράντζι), or Seville orange. This fruit is super to make marmalade and other sweets, and the tree is more drought resilient than normal sweet oranges, but saying that, 6 or 7 of them, is way too many for my needs.
So, I endeavoured to graft them, with a more palatable fruit.
I have covered olive tree, peg grafting briefly on another post, so here is a more detailed instruction for citrus trees. The procedure is pretty much the same.
A good grafting knife, or failing that, a good pen knife
Binding materials, hemp, reed, or grafting tape
An old towel, or kitchen roll, wet
The job requires a steady hand, patience and time, so make sure you`re able to meet these points. Also, timing is important when peg grafting.
1 – As sap runs thick and fast in Spring, then this is obviously the most suitable time, ie here in Crete, March thru` April. If you have a more favourable climate than Crete, then the time frame may be extended.
2 – Study your true fruiting trees for suitable donors. The thickness of the donor is relevant to how thick your root stock trunk is. If you have a root stock trunk the thickness of an egg, then the donor should be approximately the thickness of a pencil or slightly thicker. Choosing from this year`s growth a branch with rigidity and carrying more than 4/6 leaves. In the crux of the leaves, close to the leaf stem, on the upper side, there should be a small bump, like a pimple, this is an unopened bud, which will develop into a new shoot. Discard branches which don`t have this bump.
3– Preparation of the donors can be done in comfort at the kitchen table before attending to the tree in question. Chop the chosen branch to length approx. 12/15 cms. Wrap your cut end in a wet towel or kitchen roll to keep it fresh. In a tree trunk the thickness of an egg, you can usually insert up to 3 pegs successfully.
4 – On a chopping board and with your grafting knife, slice the bottom end of the branch diagonally, creating a deep diagonal slice through the branch. You should ensure that the direction of the slice leaves the potential bud on the outside of the branch when you position it later on the trunk of the tree.
Keep them wrapped in the wet towel till you`ve prepared all of your donor pegs. Don`t cut off the leaves yet.
5 – Choose the smoothest point to cut down the tree requiring the graft, where there are no scars, bumps or branches in the bark. Leave a trunk of at least 1/2 metre in height if possible.
6 – If there are branches below the cut line, then these will always remain root stock, ie undesirable, so will need to be snipped off now and later, as they re-grow.
7 – Make sure you`re at eye height with the trunk stump. Using the handle of your grafting knife, tap the bark gently in the area of the newly chopped trunk where you wish to implant the pegs. This loosens the bark.
8 – Carefully make a vertical incision, the same length as the diagonal cut on the donor branch. The technique which I find gives me better control, is to push the knife through the bark in little steps, as oppose to slicing the bark.
9 – Using your grafting knife again, but the reverse side of the sharp side, there is a hump, visible in the piccie above, use this hump to gently ease the bark away from the trunk, releasing the two flaps of bark.
10 – Before positioning your donor branches, nip off the leaves, taking care to not knock the bumps. Place your diagonally cut peg branch into the opening, making sure the surface of the diagonally cut branch is snug against the trunk. Close the two flaps of bark over the peg. If you are placing more than one peg, continue with the rest.
11 – When you have positioned your pegs, bind quite tight, holding the pegs in position and the bark flaps closed over the pegs, making sure you have covered completely the incision.
12 – Mix up a handful of local soil with a little water and place this on the cut tree stump. This keeps the procedure moist, prevents parasites and the cold from damaging the tree. Wrap cling film over the mud and around the binding, but not over the upright peg branches with leaves and potential buds
If you have overly hot weather, pop back and check the wrap for moisture and add a few drops if necessary. Check back in approx 20 / 30 days to see if you have any new shoots. It could be that the donor is still green and alive, but has no new shoots yet, be patient and check back in 10 days or so.
If you see a new shoot it means you have succeeded your peg graft! Leave the binding in place for a few days more, as removing the binding too early could jeopardize the graft.