2nd leaf Wickson suddenly looking terrible - advice?

Hi everyone. Just noticed on Saturday my two small Wickson on interstem trees in their second leaf started looking terrible sometime in the last week, and I’m very concerned!

On the first one (with angled rungs), the leaves all just kind of flooped down and are looking yellowish. We’ve had plenty of rain this summer, but I gave it a watering on Saturday night just in case. Didn’t seem to help. We have not had a ridiculous amount of rain and I haven’t watered more than one or two times, so overwatering seems unlikely. The drainage is pretty good in the raised terrace too, probably.

On the second specimen, the leaves are still perky, but have gone very yellow in a short period of time, even more so along the veins of the leaves.

These trees were doing good this year otherwise and put on something like 50cm of new growth. They have CAR spots, but not all that bad and less so than last year.

The last thing I did to these trees was paint the bottom ~20cm of their trunks with raw neem oil as a prophylactic against borers. That was a month ago, and they have seemed fine up until this week. Also, there are 6 other varieties in the same area and they all look ok. Just the two Wickson showing problems. Maybe they are two different issues on the two different trees.

I think of yellow leaves as an indicator of nitrogen deficiency, but that seems unlikely to me. These trees were planted almost two years ago into fill capped with imported top soil. I got that new topsoil tested (results attached) and it looked fine. Nutrients (other than N, which is not tested) close to good range, 5% OM, 6.7 pH. Last fall the whole bed got frosted with 3cm of compost, and earlier this season I was spraying the trees with dilute liquid fish, kelp extract, EM-1, and a bit of neem oil. I could put some N down in the form of pee, blood meal, or compost, but I worry about putting quick nitrogen down this late in the season.

I would be grateful to hear your thoughts on what the cause might be and any remedies that might be called for. Or maybe this is not a big deal and I should chill out…


Generally when I see symptoms like that (sudden wilting) I look at root problems (rot etc) and borers. Not too familiar with interstem grafting, but maybe graft failure too?

Sorry to see that, your first tree is not looking good at all. That tree might have a bad graft union. Is the shoot coming up from the ground at the base an apple? If it is apple and healthy it means the union is the problem. There could be some compatibility problem with the interstem.

Aw dang, you guys might be right about the graft. I looked around for anything obvious on the trunk by the soil, but didn’t examine the graft much. I planted these interestems not quite right since at that time I didn’t know you were supposed to put the first union under soil level. So both unions are above ground, though the lower one is close to soil level. I’ll check out the grafts tonight when I get home from work.

The shoots at the ground are indeed apple. There have been a very few suckers coming up that I cut off on some of these trees. But since you mention it, it is awful late for new growth like that. All the other growth on the top of the trees has pretty much ceased.

Grr, the thought of having to start over on these kind of sucks, but such is life.

If those were my trees I would let the shoots come up from the base and graft onto them. You have two years of healthy root growth there. The interstem is not really necessary if you keep on top of the pruning. If you replace them I would also not use the same interstem combo, there might be a problem with Wickson on that combo.

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The grafts seem ok, but I have no experience to know if what I’m looking is normal or not. The shoots are coming out of the M.111 lower part; nothing coming out of the G.11 section. The G.11 to scion graft doesn’t look bad either. So I don’t know. I’m wonder if the graft could somehow have been harmed by the neem oil I put on it last month.

I had thought if a graft took and grew well for a year, it would have it made unless it got broken by a storm or something. Is it common for a graft to fail a couple years in?

Attached are some pics of the two graft areas on the worse looking tree.

I don’t know about grafting right onto M.111 with Wickson. The space I want the tree to take up is about 2.5 meters tall. Wickson is reported to be on the vigorous side, so I would fear on M.111 it would just want to get huge and I’d be fighting it with pruning. Might be tough to get it to settle into bearing and if for some reason it got ignored for a couple years it might be a problem. On the other hand, it does seem a shame to waste those roots.

We’ll see what happens with this, but I might consider grafting something like G.202 onto the M.111 shoots and growing it up to form the leader for the multigraft espalier. Then the varietal scions would get grafted onto the rungs.

Thanks for the advice guys.

The mismatched size there is odd for an interstem, the G11 should be smaller not larger. I am not an expert on interstems though.

The top 2/3 of the interstem has a darkened bark. Is that where the neem was?

I have used the neem on young peach trees with no problem, but not on apples (I don’t have apple borers). I would be surprised if it caused problems but you never know. Did you use raw neem?

Note that you don’t really see much in a bad union, only when you dig up or cut into the tree is it apparent it is not transferring nutrients. You can use a knife to probe some sections of the bark to see how live it looks. Green/white good, brown/tan bad.

My initial impression was this must be a root problem. However, the shoots coming up from the roots look very healthy. I don’t have a tremendous amount of experience with grafting, and zero experience with interstems. Unfortunately I do have experience with both borers and root issues, like crown/collar rot. Based on the health of those shoots, I don’t think it’s a root problem.

I’m also finding the fatter interstem weird. I have 5 trees on interstem and they all look like that, though this one is among the fattest. 4 are G11/M111 one is B9/B118. No idea if that is expected behavior, but up to now the trees were pretty healthy looking so I figured it was normal.

Good call on testing with the knife Scott. What I found this morning was that the M111 part looks good, the G11 part is dead, and the Wickson part is living (but rapidly failing given how the upper section looks - even worse than the picture now). See pics attached.

Same thing on the other failing Wickson, though on that one I noticed in the G11 section there are two different looking areas. Testing with the knife, one little part is still living while the rest is brown. Going back to the central tree from the pictures, you can actually see on the G11 part that there is a section down toward the M111 union that is still alive.

So what seems to be the case is that the G11 interstem has died for some reason, while the M111 and the varietal are ok. If it was a graft issue, I would expect the lower section to be ok and the upper dying, but this is a more bizarre situation with the middle section crapping out. Some of the trees are worse than others (the Wicksons are worst, maybe a coincidence) but all show damage. I have two trees on G30 and those look ok. Also the B9/B118 looks ok.

I guess at this point my conclusion is that G11 will die when coated with straight neem oil in late summer? I used raw neem applied with a paintbrush at the end of July.

Any other possibilities to entertain besides the neem treatment anyone can think of?

I’ll make a more detailed inspection for dead sections and make a list of anything that is affected besides G11, varietal or rootstock.




Wow, thats pretty odd that only G11 would be so sensitive to neem. Sorry that you had to be to discoverer of that. At some point I looked up studies and there have been several uses of raw oils on apple stocks for pest control and I never found a mention of any issues for the tree.

Well, live and learn. Maybe this thread can save someone some trouble at some point in future.

I had read both that thread with neem on peach trees, as well as a discussion at another forum regarding brushing straight neem on apple trees, so I thought it would be fine. I’m sure it won’t be the last challenge to face, eh?

I looked over the other trees again last evening, and it really is only the G11 pieces that are showing damage at present.

Boo-hoo! :frowning:

I just looked through my inventory and I have some G11 trees I bought around the same time as your wickson. I am going to paint them with raw neem this weekend, one side only so I don’t kill the tree, and will see what happens.

I wouldn’t completely rule out graft failure, I have had several problems with G11 myself. One of the G11 I just found in my inventory broke off as I planted it - just moving it in the hole to seat it properly caused it to break at the union. I cleft grafted a couple varieties to it so I still have the root. I also lost several other G11 trees in previous years with breaks at the union. G30 has the bad rap on that but for me its been all G11 with the problems.

Did the neam kill anything?