Quercus suber - Cork Oak Health


(B) #1

I was hoping to get some help, as the Quercus suber I repotted months ago seems to not be doing so hot.

As I watered this morning, I bumped into the tree and had some leaf drop. I had been noticing some browning of leaves over the past week, but now it seems like things have turned for the worse. I still have buds emerging and some leaves emerging from bud, as well as some verdant green new foliage.

I have been checking soil wetness regularly, checking visually in on the tree every other day or so, etc. I wonder if the tree is just finally showing shock from a significant root prune and repot? This was the first potting from a 15 gallon nursery container, fyi. I did the repot in Mid January. I am using a 1:1:1:1 mix - akadama, pumice, lava and kanuma mix.

Photos below, and thanks for any help! Cheers.


(Frank Corrigan) #2

It would help to know the climatic zone and location. Also what other work has been done to the tree in the same time frame. A repot in January may be perfectly fine in some climates but not in others. When you say significant root prune, did you mean bare root?


(B) #3

Hey there Frank, thanks for the response - I am in North County Coastal San Diego, USDA Hardiness Zone 10a. As for additional work done to the tree - the tree had been pruned back by the nursery before purchase, but they could not tell me exactly when. I did wire the tree in early fall of 2018, before the repot in January 2019.

As for the root prune - I pruned away 50% of the roots and soil in the 15 gallon container, but left a fair amount of original soil around the existing roots for repot. I chop sticked the soil away from the very start, and after revealing roots, I used root pruners to cut the exposed pieces - the process took a long time(expected) - all while spraying the roots to keep them moist or wet.

I sifted my soil mix and placed a nice base layer with the larger pieces at the bottom(1/2" - 1/4"), then filled in the 1:1:1:1 mix I created(1/2" to 1/8") and chop sticked it into the voids where the roots were no longer. I then covered the soil in white sphagnum to keep in moisture.

I have heard and read to never bare root any tress except deciduous trees, is that your experience?

Thanks again!!!


(Frank Corrigan) #4

Thanks for the additional information. I suspect the tree is responding to the repot and the amount of work done within a short time frame.
I would place it in partial shade and keep it moist but not too wet. Give the tree a rest for the rest of this growing season. Once it is showing signs of good recovery then begin light fertilization.
Generally speaking the bare root process is reserved for deciduous, however i have used it with conifers in specific circumstances. Emergency repot, difficult collections, but always with additional aftercare to compensate for the bare root process.
I would also caution against using the bare root process with deciduous regardless of circumstance. It is simply one method for certain species and conditions. Best to learn the recommended repotting techniques for each species.


(Jonas Dupuich) #5

It’s very common for oaks to drop old leaves this time of year, especially after a big repot. It’s good to hear that the buds still look good. The main thing at this point is to watch the water carefully along the lines Frank mentioned. Only watering the soil when it begins to dry out a bit is a good approach.

Watching the buds will be the best indication of how the tree is doing.

Do let us know how it goes!


(B) #6

Frank and Jonas - I want to thank you both for taking the time to write.

I will keep everyone posted on progress, and watch my watering closely; as well as the bud health.

Again, I am very thankful for the responses.

Best, Bret