Cork Oak Acorns

[leatherback]

Have you also tried "Holly oaks"? I found them all over Corfu, Greece. Very beautiful shrublike trees on coastal cliffs. Leaves are quite small and prickly, similar to holly. Would make for a very cool bonsai. My acorns did not germinate however.

nope. Never tried

 

[leatherback]

I have a large cork oak bonsai and a cork oak that I have put in landscape here to see how it does. Since living in NC, I have lost one smaller tree due to cold, so these are definitely more cold sensitive than my olives, which sit outside 365 days per year. Because I am nervous about my large cork oak bonsai, I am treating it like a semi-tropical, and giving it protection any time temps drop to the lower 20's F.

That said, the cork oak in landscape appears to be doing fine, but I have only owned it about three years...

thx

 

[BaKiBonsai]

All of this is Holly oak

 

[WNC Bonsai]

Here’s how Mrs. Ohno does it. The Japanese seem to have this method down pat when it comes to creating mame and shohin trees. That’a a Japanese oak in her hand.

 

[Veni]

Germinated ~4ish species of Oaks from Southern California which is a similar Mediterranean climate to Spain. Most of my subtropical oaks didn't require cold stratification but it may still increase germination efficacy. Oak acorns seem to have a low germination rate as they're prone to insect damage and fungal/microbial problems, often providing a staple food for many different critters and microbes. As such you can get a lot better germination by being selective with the acorns you pick up (ie acorns with the caps on that have fallen off the tree usually signal insect damage). For example, I believe the US Forest Service quotes the California Black Oak as 30-50% but I've seen more like 70-90% the last few months by being selective. The more you harvest acorns the easier it is to pick up on damage markers too! I've also had luck with perlite and can see the argument for using it over wet paper towels due to there being less organic material for fungus to eat/establish on.

1. Collect acorns or seeds. Ripe acorns will twist off easily from their caps and do not have damage/insect holes.
2. Soak them in warm water for 24hrs (150F or 65C), discard the floating acorns.
3. *Optional* Rinse the sunk acorns in a 3% Peroxide solution (15- 30secs).
4. Wrap the seeds with a lightly moist paper towel (fully wet the towel and then squeeze excess water out) and put them in a Ziploc bag.
5. Put Ziploc bag in the fridge to cold stratify (minimum 1 week) and as they send out their first root radicle, take the Ziploc bag out of the fridge and leave it at room temperature, checking every couple of days.
6. Once root is ~1/2 inch you can plant them in soil!
7. Be patient as they send out their first set of leaves (cotyledons)!

Bonus Picture of what I think is a California Blue Oak:

 

[WNC Bonsai]

Interestingly I was watching a video by Mr Maple on germinating J. maple seeds and they recommended dusting the seeds with captan fungicide. They germinate thousands of seeds each year and do this on all of them. Might be good to try that out on other types of seeds.

 

[Bonsai Nut]

Interestingly I was watching a video by Mr Maple on germinating J. maple seeds and they recommended dusting the seeds with captan fungicide.

Just saying - Captan is a probable human carcinogen. Be careful if you use it, and wear protective gear (gloves at the minimum, and don't inhale any dust).

 

[WNC Bonsai]

Just saying - Captan is a probable human carcinogen. Be careful if you use it, and wear protective gear (gloves at the minimum, and don't inhale any dust).

I agree and I think if you check, many of the insecticides and fungicides we commonly use are classed as potentially carcinogenic. Hopefully folks are aware of this, read the labels on the containers, and follow safe handling and application practices.

 

[Bonsai Nut]

I agree and I think if you check, many of the insecticides and fungicides we commonly use are classed as potentially carcinogenic. Hopefully folks are aware of this, read the labels on the containers, and follow safe handling and application practices.

It is just interesting that it came up because Captan had an EPA review this summer where they changed some of the guidance. If you are handling it commercially, you're supposed to wear a respirator, protective clothing, and rubber gloves. I saw the video you were referencing, and the guys were handling it with their bare hands

 

[leatherback]

Not sure why this discussion is taking place on fungicides for my cork oak acorns.

The acorns were planted a year ago and grow to about 30cm. My main challenge so far has been that mice are taking an above-average interest in these. This winter again about half of them were bitten off at the base.