What do you think is going on with this Zelkova?

[John P.]

I recently lost an air-layered Zelkova (from this same tree) to the same thing a month ago. Leaves emerged, got droopy, and died. The layer wasn’t large or strong enough and died.

I grew this Zelkova from seed a number of years ago, so I hope not to lose it.

I thought I saw slug slime on the air layer I lost, and just thought that’s what killed it. There is some sort of insect damage as shown on the larger leaves of this tree. The branches with the drooping and dying leaves are still green under the bark.

I’ve been spraying with copper every 2 weeks before it had any leaves break.

Any ideas?

 

[Brian Van Fleet]

Guessing it’s a root issue. Maybe it got too dry, or they can’t keep up with the transpiration. The lower area still looks good, so hopefully it’s stable in the pot, the pot is stable in the ground, and with a little warmth, the roots will catch up.

 

[MrWunderful]

You spray it with copper every 2 weeks?

 

[John P.]

Just as they were leafing out ...

 

[0soyoung]

You've got lots of healthy foliage low. The problem 'wilty' foliage is away on long older shoots. Like @Brian Van Fleet indicated, the water supply to those leaves is likely inadequate. Given everything I see, I think something has reduced the water carrying capacity of this long stems with wilty leaves. IMHO, you have a few options:

1. look closely at those long shoots - is there anything curious in the region between the highest normal, healthy green leaf and the lowest wilty ones?
   1. bark damaged?
   2. funny discoloration?
   3. strange bumps?
   4. etc.
2. just wait and see what happens with those long shoots.
   1. they might recover
   2. they may just turn brown and die
      1. then remove the dead stem just above the last good, green leaf and perform an autopsy to see what was going on in the xylem (wood)
   3. does the wiltiness progress downward?
      1. if yes, a pathogen in the phloem (inner bark) is indicated --> remove the stem below the highest normal green leaf.
      2. if no, there may well be a pathogen in the xylem (wood)
3. remove the wilty leaf stems just above the last unwilty green leaf.
   1. the wilty leaves don't produce much if any photosynthesis and aren't helping in any way
   2. there is plenty of good foliage low down to power root growth.
   3. perform an autopsy to see what is going on in the xylem (wood).

 

[John P.]

Thanks so much for your thoughtful reply! Much appreciated.

Will report back.

 

[John P.]

Well, I picked off a bunch of small green caterpillars and one slug off of the Zelkova just now.

Also cut my leader way back. It was olive greenish-gray under the bark and throughout the wood, and crispy in other parts.

Cut back the leader to the part photographed below (a full season’s worth of growth). Seems alive, but I’m not so sure about the color of the wood. The piece I cut in half below was right above the top-most part of the leader presently.

Any thoughts?

 

[Tbwilson33]

From working with trees on a day to do basis zelkova is not susceptible like other species. They are often planted regularly in cities because of their disease resistence and insects don’t desire them. I don’t think you have anything serious. The cut section you showed doesn’t tell me it it’s anything vascular.

You really made me do my homework. This is the only known disease of zelkova. This is out of the disease management guide by the state of Connecticut agricultural department. They give these books to arborists or studying arborist but I’m sure you could get one if you asked from your state agriculture department. I’ve been doing trees before i started doing bonsai hope this helps

 

[John P.]

Interesting. Yeah, I always consider Zelkova to be pretty bulletproof. Not sure what’s afflicting this guy, but hopefully it’ll pull through.

 

[0soyoung]

Being spring, this zelkova problem doesn't fit with my experience as being nectria caused. In my experience, nectria manifests its presence in the summer/fall when most fungi produce fruiting bodies. Foliage on an affected stem will suddenly wilt, dry to brown, and remain attached. Nectria's distinctive little orange fruiting bodies emerge on the bark in the area of the infection about the same time or shortly afterward.

This event would fit with being caused by verticillium but for the fact that the autopsy showed no dark rings/streaks in the wood.

Stay attentive @John P. for any reappearance of this problem. While we don't know what caused it, we can be reasonably confident it wasn't either of these well-known pathogens. Hopefully this 'event' will prove to be nothing more than just 'one of those things'.

 

[ConorDash]

You got some seriously good replies.. wow.
Although I hope my trees never befall such misfortune, I can only hope if I posted, I’d get as good of a reply!

Well done and thanks for the replies @0soyoung & @Tbwilson33

 

[John P.]

You got some seriously good replies.. wow.
Although I hope my trees never befall such misfortune, I can only hope if I posted, I’d get as good of a reply!

Well done and thanks for the replies @0soyoung & @Tbwilson33

I agree—what a great group!

 

[John P.]

The leaves near the top of the cut—indeed all of them on the leader—are now wilted. After squishing some additional caterpillars I performed an experiment to see how quickly the container would drain.

Hardly at all.

Raised the rootball up, put some pumice down, and now it drains quickly.

This would definitely explain what’s been going on. I think it got compacted with organics and root growth. Now I just hope the leader can put on some new growth before it dies back.

Do you think I should fertilize or let it be?

 

[Tbwilson33]

Would have never guess the soil was that poorly draining from your photos. You probably don’t need to fertilize for it to recover if that was truly the issue