Revive Seiju Elm after pest attack

[AGentleman]

Hello there,
I went away for two nights and came back to see the young Seiju elm that I planted in the ground has had most of its fresh spring leaves eaten off and others browning. I couldn’t see any insects but I suspect that it is red spider mites. I shook the branches onto some paper. I ran my finger across the debris and smeared it but the smears weren’t red. Could these be dead mites? There’s no fine webbing visible in the branches either.







Should I spray it with Neem oil? Also, would it hurt my other trees to have a preventative spray of Neem oil? I’m not sure if spraying trees too much can hurt them.



The tree was very healthy when I root-pruned and planted it in the ground just over two months ago. I had wired the branches out for fun prior to planting. About a month ago I sprayed it with Yates Rose Shield. It is now mid Spring down here. It was slow to get going and the buds had only developed into leaves. It had not started pushing like my other trees. I thought that was because it was not in as good a position lower on the ground. It could have been under attack before I left but I didn’t notice.
I have taken the wire off but will probably wire it back onto some stakes because it’s still a little bit wobbly.
I fertilise it with Dynamic lifter (organic fertiliser pellets), blood and bone. And weekly I give it some organic liquid fertiliser. I also water it a lot. I wasn’t worried because it was planted in the ground and thought it would drain well.
Is there anything else I can do to help it recover?
Thanks,
Greg

 

[Shibui]

Mites have very tiny mouths. They cannot bite chunks out of leaves like this. Mite damage is caused by them sucking sap out of the leaves. Mite damage generally occurs much slower than this and would normally show up as yellowing leaves rather than chewed leaves.

My first guess would be possums snacking on your elm. How tall and how rigid is the mesh guard around the tree? I suspect most hungry possums would just climb right over that. I'd try putting some sort of cover over the top.
Possible caterpillars but they would normally be visible on the branches.
Rats occasionally take a fancy to branches but I haven't seen them eat that many leaves before.

Plants in the ground don't usually need such regular fertiliser as nutrients do not leach away as quick as in pots. I'd back off to monthly fert.
It is definitely possible to overwater trees in the ground. How often to water will depend on the soil type. Clay soils hold lots of water and plants in clay can easily become waterlogged, especially if you've excavated a hole in clay soil and filled it with a different soil mix. Try digging down in the soil near the tree to see if it's saturated, damp or dry. Only water enough to keep the soil around the tree damp. A good weekly watering should be enough for most trees in most soils.

 

[AGentleman]

Thanks @Shibui
I took the main guard mesh off for the photo shoot. It's a lot taller but a possum could have wiggled through. I've put more mesh over the top now.



Unfortunately, the possum around here developed a taste for Seiju last spring. It clawed through a plastic bag and ate my cuttings.

However, if it's a mammal, it could be rats. The neighbour over the back fence has chooks (and an amazing tomato garden). It will be difficult keeping rats at bay!

Well, regardless of what munched the leaves, I'm definitely over watering and over fertilising. Thanks for clearing that up.
Greg

 

[AGentleman]

Thanks @Shibui I never would have thought a rat or possum would have caused this damage.

After your reply, I shored up my mesh and I now know it's a pesky rat trying to eat my apparently tasty Seiju leaves. They must be quite the delicacy because the bugger tried to get at them three times while completely ignoring the bog standard chinese elm leaves which must have practically tickled its nose whilst it was frantically digging.



I now know what I need to do.

However it is quite the set back for my poor elm for which I had such high hopes. It's missed the majority of spring. If it doesn't grow that much this year, do you think it would be wise to forgo lifting it for root pruning this coming winter to let it gain strength?

Thanks Greg

 

[Shibui]

My experience is that Chinese elms take at least a year to get really going so no problem leaving it this winter, especially after such an inauspicious start.

 

[AGentleman]

Thank you

 

[AGentleman]

Unfortunately, I’m certain this elm died. I’m going to leave it in place until next spring.
Not because I’m an optimist but because I’m a masochist!



However, after a couple of days of persistent rain, a gel like substance appeared at the tip of the longest of branches. There were about ten branches effected which is probably about a third of the branches.





I'm curious about the cause of this gel.

The tree was overwatered and over fertilised when it still had leaves but that was almost a month ago.
Could it be from slugs? The branches are so thin that I doubt they could support the weight of a slug (although I have to admit to never weighing a slug).
Also, about a week before the gel formed I used a product called Plant Starter on this tree. I liked the name of that product and thought I had nothing to lose. It contains both Indole Acetic Acid and Naphthalene Acetic Acid which might be growth hormones. Could this have caused a last ditch effort on the tree's part to produce gel at it's old growing tips?

I'm keen to learn about growing out Seiju in my garden because I'm going to try again next year but this time with TWO Seiju elms. Double the jeopardy! I might even see if there are any threads on here about ground growing.... (just kidding)

 

[AGentleman]

This is a photo of the tree in May on the last day of calendar spring. It had grown really well in it's little pot from the nursery.



Before planting in the ground I pruned it's roots from this



to this



Another thing struck me about this tree is that none of the cuttings or root cuttings I tried to propagate worked. In the one year that I've been taking cuttings I've had pretty high success including cuttings from a different Seiju elm.
hmmmm.. oh well,
Thanks for reading.
Greg

 

[Charlo]

Hi Greg, I recently bought a starter Seiju elm and I am excited to grow one after watching this video

. In fact I plan on buying another one. From the first pics sure looked like something was munching on the leaves of you tree. I am curious about your root prune since there still seems to be a high root on the right side. Were the roots pruned to create a good nebari? Do you feel there were enough roots left to support the tree? I know some types of trees can survive on very few roots.

 

[Franck L]

DED Dutch Elm disease, check for beetles that are the vector. Replacing the tree and plant a new one at place is not a good idea.

Dutch elm disease - Wikipedia

en.wikipedia.org

 

[AGentleman]

Hi @Charlo

Thanks for that YouTube link. I very much enjoy Bonsaify videos for both the delivery and content. I'll watch this one tonight when I'm sitting by youngest as he drifts off to sleep (and try not to myself).

This is only my second year of root pruning so I don't really know what I'm doing! This year I've had the mindset that if I can't get good roots then the tree won't make a good bonsai anyway. However, I'm pretty sure I've gone too hard on all my trees considering my skill level. This wasn't the only tree I killed. A nursery cotoneaster looks like it's gone too and another just hanging in (although my wife is sure it's dead too).
Having said that, I've been told Chinese elms can handle a hard root prune. Perhaps the Seiju variety needs to be treated more gently. BUT I'm almost certain it wasn't the root pruning but the overwatering and over fertilising that severely weakened the tree. Whatever attacked it while I was away was the last straw.

As I mentioned I'm really a beginner with root pruning. My plan with this was to angle the tree more when I planted it. It's not the best angle to demonstrate this but if you can imagine the tree leaning to the right slightly toward the viewer.



I guess it's heading towards winter where you are but I'd love to see what you do with your Seiju.

Greg

 

[Shibui]

I've had plenty of Chinese elms produce gel as a reaction to water on wounds. It's particularly prevalent when root pruning but does not seem to indicate any particular problem. The vast majority of my Chinese elms go on to grow perfectly healthy after showing gel.
This is NOT Dutch Elm disease which we do not have in Australia (yet)

Chinese elms should be able to cope with a reasonably severe root prune. Seiju is no different to other Chinese elm vars in my experience.
I'd also put this death down to the combination of factors you mentioned rather than the root prune alone.

 

[rockm]

The mucilage secretion is not uncommon in elms. It is a response to disturbed tissue (chewing insects primarily which the tree tries to overwhelm with goo to stop) slippery elm for instance is named for the secretions

BTW immediately discount any “advice” about Dutch Elm Disease. Whoever mentions it doesn’t really understand what they’re talking about.

That disease is hardly an issue for bonsai elms. The DED fungus is spread primarily by flying bark beetles high up in mature elm trees moving from infected to healthy mature elms. Bonsai aren’t tall enough to attract those beetles. Never say never but it would be extremely rare for an elm bonsai to contract DED

I suspect your elm died of several factors overwatering, overly agressive root pruning and agressive wiring and bending

Watering is hard to learn. Do a search on how to water here

FWIW wiring is not effective on deciduous trees for the most part. Most great deciduous species bonsai are “built” using the grow out and prune back hard method. In agressivy bending larger branches you crack tissue and split cambium sometimes visibly sometimes the damage is t visible. In any case such crack and split ls can weaken the tree

Live and learn. Everyone who has been doing bonsai has made mistakes

 

[shohin_branches]

The gel is a feature of inner elm cambium often referred to as elm mucilage, it was used often in early medicine for soothing sore throats. Slippery elm (Ulmus rubra) is the best at making it but most elms create it. Soak some inner elm bark in a bowl of water for an hour and then stick your hands in it. It's still used in many teas for sore throats.

 

[AGentleman]

Thank you all for sharing your knowledge. You really are amazing and helpful. Although I'm not sure I'll but tossing out my cough lollies anytime soon.
Yes @rockm I'm finding learning how to water very difficult. I'm glad @Shibui told me explicitly that you can overwater trees in the ground (he's saved the lives of my future trees) but I gather watering is something you gain from experience. I find it hard to tell the difference between dry and moist soil especially with inorganic soil. I also get frustrated when some trees respond with the same symptoms to both over and under watering! I'm only in my second year and this year I'm doing much better.
Anyway I'm sure everyone's got much better things to be doing so I'll stop babbling.
Thanks again,
Greg