I am attempting to grow an oak tree that has a lot of sentimental value to me. It is almost 2 years old now and has survived one summer in Montreal and one in Ottawa. It currently resides at my parents horse (with a north facing yard) but I would like to be able to keep it mobile until I find somewhere permanent to settle and plant it.
Last winter it was inside a house and sprouted leaves early because of the early exposure to heat, but it survived and thrived outside all summer growing 4 new leaves and adding 3 inches!
Now with winter fast approaching I am looking for recommendations on how to maintain it over the. I would like to keep the tree in a pot, but am not sure if it should stay in the current size or be moved to something larger. Also looking advice on whether to keep it inside or outside, or plant the tree (in the pot) in the yard for the winter.
Thank you for contacting Toronto Master Gardeners.
Oak, Quercus sp., grow to a large size with a huge root system. Maintaining a seedling in a small pot for an extended period is not going to encourage a strong root system. You will end up with encircling roots that will ultimately strangle the trunk. If you are not able to plant it in the correct spot for a few more years you are better off planting it in the ground now and transplanting in the future. You will have a much stronger tree this way. That is essentially what nurseries do. If you will be able to plant it in it’s final destination within the next year then it will definitely need a much larger pot. You want the roots to be able to fan away from the trunk and not encircle the pot and trunk.
The ideal time to transplant trees is right now in the fall. If you will be keeping it in a pot then dig the pot in the ground so the roots are protected and it is mimicking the natural year round environment it would have if it were planted in the ground. This will make it a stronger tree.
There has been much research on tree planting in the past 10 years and new protocols for successful planting have been developed.
It is important to ensure you transplant the tree correctly either way. Remove the tree from the pot and use running water to wash off the soil from the roots. This will allow you to see the root structure and untangle and straighten them out. If there are any roots encircling the trunk trim them off. When planting ensure the tree is not buried too deep. The spot on the trunk where the roots branch off is the flare. The flare should be above the dirt with the roots just below the dirt spreading out horizontally. Trees keep their roots close to the surface for access to oxygen and water. Mulching around the tree helps maintain moisture. The mulch should not touch the trunk. When planting do not add any fertilizer to the hole. The soil filling the hole should be the same as the soil around it to encourage roots to grow away from the trunk. Give the tree deep watering when dry rather than frequent light watering.
Here is a link that walks you through tree planting: https://s3.wp.wsu.edu/uploads/sites/403/2015/03/Planting-fact-sheet.pdf
Good Luck with your tree, I hope it finds it’s home and grows into a beautiful specimen.