Two years ago a coast live oak I’d been fond of for many years came into my collection.
Coast live oak – January 2017
I’d enjoyed watching the tree develop over the years and was looking forward to working on it. Before getting started, however, I repotted the tree to get a look at the roots. What I found surprised me.
As I pulled the tree out of the pot, half of the soil fell away. It turned out there was dieback on the left side of the trunk – the side where many of the roots originated. I potted the tree carefully and waited to see what would happen.
Dieback on the left side
The live half of the trunk
Very little, if any, new growth appeared that year. I watered only when the soil was dry, which was sometimes every 1-2 weeks.
Last year, a small amount of new growth appeared. I continued watering only when the tree was dry, but the tree was beginning to dry out faster and faster so I knew that the roots were active.
The tree is now sending out new growth again, as well as some flowers. Here’s how it looks today.
Coast live oak – 17″
The spotted, yellow, leaves are the last remaining leaves that grew in 2016. The spots reveal signs of fungal damage commonly found on otherwise healthy oaks in the area. I have yet to identify the culprit.
2016 foliage showing fungal damage
The strongest branches now have up to a dozen leaves from last year and another handful of leaves that are emerging now.
2018 and 2019 foliage
This isn’t enough new growth to indicate that it’s time to work on the tree. Especially since much of last year’s foliage shows signs of hail damage from a spring storm last year.
2018 foliage – grey spots indicate hail damage
I’m not sure what led to the initial dieback of the roots. I suspect that several factors contributed which is why I’m taking a conservative approach – no pruning, careful watering, and a generous-sized pot.
I expect it will be time to repot again in another year or two. Once I can establish that there are lots of healthy roots and I see signs of more vigorous growth, I’ll get back to the process of refining the branches.
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Christine Weigen says
What is your preferred soil mix for Live Oaks?
Thanks for great posts!
Jonas Dupuich says
Hi Christine! I’ve used a number of mixes depending on the situation. A mix of 30-50% akadama appears to work well.
Lars Grimm says
Do you think there was new root growth in the area of dieback or just compensatory growth in the other areas? I’d love to see some repotting pictures when you work on this one again.
Jonas Dupuich says
Hi Lars – good question. I’d guess there are no roots at all on the left side of the tree. I’ll be curious to see if I can learn anything the next time I repot, but am not sure that I’ll want to dig all the way back to the base of the trunk to find out exactly where they emerge. Am currently thinking about repotting next year. Thanks!