North American Fruit Explorers mailing list at ibiblio

[Steve <sdw12986@aol.com>]

Thanks to the several of you who replied.
I can think of 2 possible explanations for what happened.
1. Sunrise apple trees have the ability for their cambium layer to turn brown when it is dormant and green up again in spring. I kind of doubt this and it will be easy to check. I could go out there this week some time and see what the cambium looks like before we get to the coldest part of the winter. (It's only been to about 10 below so far.) For sure I will be checking in late winter after the snow melts enough to make it easier.
2. I had a one in a million coincidence and between collecting scion wood and a little light pruning I just happened to cut off every bit of winter killed wood without leaving even a bit of it on the tree. OK, maybe one in a thousand since collecting the scions, I did target the more vigorous upright growth. That one is a little hard to believe too.

I'll be watching this situation. Maybe something will make some sense eventually.

Steve


Steve wrote:

476C878A.3020501@aol.com" type="cite">
OK, a whole week has gone by and I got not a single answer or even a comment.
Maybe I was right? Maybe it was so long that nobody actually read all the way down to the question?
Or was it that what I described is impossible and (like me) nobody else here has a clue how this could have happened?


sdw12986@aol.com wrote:

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Why is this my BIG question?
1. This is the question I was pondering last spring that made me decide to join this group.
2. It will probably end up so big that people will get bored and stop reading.

When I first joined this group, last spring, I introduced myself and told about how I have 4 apple trees, 3 of which I grafted to multiple cultivars. (I grow other fruits too but this is an apple question.)

Spring of 2000: I obtained 5 or 6 different apple scions and added those to what I had growing on my apple trees at the time. I had high hopes for Mantet and Red Baron so I grafted one branch on each of 3 trees with those two. Other cultivars got one branch grafted. Then there was Sunrise. I ran out of prime locations so made just one graft on a lower branch of one tree. It was a branch that I had originally expected to prune off after the tree got bigger.

Summer 2006: It was a great year for apples that year and I got my first good crop of Sunrise. I loved it. I wished I had made 3 grafts of that one and only one or 2 of Mantet and Red Baron. I would have to correct this.

Early spring 2007: I collected scion wood from my own branch of Sunrise and also from Chestnut, which I liked well enough to add another branch somewhere. The scions of Sunrise looked dead. The cambium layer was brown. The Chestnut scions (and other apples that I cut, just to compare the cambium) were all normal and green.
The winter had been an odd one. Temperatures in the 40s and some 50s right through the middle of January followed by a sudden plunge into the -30s on several occasions over the next 6 weeks. I figured that must be the end of my Sunrise. I cut several more scions looking for some hint of green cambium. I stored them away, except for 6 scions which I tested by placing them in a cup of water in the kitchen window. Two of those showed a little life and opened some green bud tips. I decided to go on with the grafts and try to save Sunrise from extinction in my yard.

Late spring 2007: I made 3 grafts with my questionable Sunrise scions, along with about 15 other apple and pear grafts. I had 100% success with the pear and all the other apple grafts but the Sunrise grafts were completely dead.

Summer 2007: Now here's the weird part. I expected my Sunrise branch to be dead since every scion cut and every pruning cut showed brown cambium and since the scions didn't even try to grow. But no, it was just fine. It leafed out normally. I expected that maybe it would collapse and die soon after leafing out but again, no. The entire branch grew fine and healthy and produced another nice crop of Sunrise apples. (They ripened a full 3 weeks later than the year before and I wasn't as thrilled by the quality, but I could say that about most of the other apples I grow.)

So finally, the question. How can this be? How is it possible for me to find brown cambium every where I looked and have the best of the scions prove to be dead when I grafted them but then have the entire rest of the cultivar grow happy and healthy anyway?

Steve in the Adirondacks

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