Even if one of your olive trees has died due to freezing, it’s possible to grow it back. Growing a frozen olive tree back from the stump ensures it will be hardier.
The regrown olive tree will resist cold weather and freezing better in the future.
As an added benefit, it’ll grow back faster than planting a new tree from scratch would: the root system is already in place.
If the tree was grafted, hopefully part of the grafted variety is still alive. If not, you’ve lost that and only the root stock will grow back.
How to prepare the frozen tree
Wait until the last frosts are over. Wounds in cold weather would increase freeze damage to the olive tree.
Then, do the following:
- Cut the dead tree trunk off cleanly, half a foot (15cm) above either the graft joint or ground level, depending on whether it was grafted or not.
- You might need to do this in two steps, first tumbling off the most part of the dead olive tree, then making a clean slice for the stump. Notch the bark before cutting large pieces off, so that slivers of bark aren’t pulled off from the trunk as they fall.
If your tree was grafted, see steps in the following paragraph; if not grafted, skip it and follow steps in the one after it.
Regrowing grafted olive stumps
This is for grafted olive:
- Sprouts may have grown above the graft joint. Keep all of those in the first year.
- Cut any growth from the undesirable root stock.
- In the 2nd year, select 3 or 4 nice shoots and cut off any other ones.
- In the 3rd year, select the most vigorous growth from the grafted part and cut other ones off.
- Train and prune this single stem in the following years to create new scaffold branches and fruiting branches.
If no shoots sprout back from the grafted part, let the root stock grow back as described below. Once it has grown back, graft the desired variety on top of that. Your new graft will benefit from part of the old rootstock’s cold-hardy experience!
For non-grafted olive trees
- In spring, sprouts will come up from the stump and from nearby roots. The first year, keep all new stems.
- In the 2nd year, remove all stems immediately on the stump. Keep those that are further off and that grew from the roots.
- In the 3rd year, select and keep 4 to 6 of the most vigorous stems, each coming from a different root.
- In the 4th year, select the most vigorous stem and start training it as you would a young olive tree.
- You can cut the other 3 to 5 stems and their root away from the original stump, and use them to plant new olive trees further off.
Basically, you’re letting the frozen olive tree grow back from its roots, as if you were preparing a root cutting.
With these techniques, you’ll be able to grow olive trees at the threshold of their climate zones. With luck, some of them will live to be 1000 years old!
Note that at the beginning, it helps to winterize young olive trees as they grow back.
CC BY-ND 2.0: Derek Winterburn