Is this growth cedar apple rust or a witches broom?
I am guessing cedar apple rust but I have never heard of that on a procumbens juniper
Thanks in advance for your help!!
Sorry to say it is cedar apple rust. My own recommendation is isolating and getting rid of the tree. Or risk infection of other junipers in your collection.I have just lost a Sabina juniper to it. I have been wiring more and more movement into it over the last few years. It had been in a well ventilated greenhouse all winter to protect it from excess rain and 4!days after I moved it outside, the first rain we had had in 3 weeks it erupted all over the tree.
Get rid of it.
There’s no cure, I had a cedar with this issue and I had to throw it out.
Wow
OK thanks for the info
Same thing here it was in a super well ventilated shed with a heater set to 34 degrees Fahrenheit for the cold winter.
They went outside a little more than a week ago.
It has been raining here and boom it just grew in a short amount of time.
Probably the entire lot is effected..
Guess I’ll be cutting down the wife’s crabapple trees asap
So I got the saw out to chop down the crabapples only to look down the street and see at least 3 more in my neighborhood.
Flowering crabapple is a common ornamental tree here in the Northern Vermont…
Tomorrow I will drive around and take a peek, what I read is any tree within 2 miles could be an issue.
This is the first time I have ever see this in my area, but I did get two Eastern Red Cedar bonsai last summer so I wonder if the spores have spread to the other junipers & cedars..
Darn I really like these junipers.
I have researched some organics that may help with preventing it to occur but I am past that point, this year..
It’s like a scene straight out of The Last Of Us! 
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For those on the thread recommending to throw this out:
Is it not possible to salvage the tree by removing the affected area and following up with anti-fungal treatments during overwintering periods? From what I’ve read it seems that this infection is localized and not systemic through the entire tree (but please correct me if I’m wrong)
I had one that I tried salvaging for years.
Cut it back, treated it with everything under the sun.
The disease kept coming back while the tree slowly withered away.
After about 6 years of trying to fix something that’s not really fixable I gave up and tossed it.
IAt that point the tree would have died anyway.
I think everyone needs to evaluate their own situation and decide on this. In my experience of losing 2 junipers the infection was generalised with all sections of the tree being infected. Not systemic but definitely generalised so cutting out the infection was not possible, because all you would be left with would be the roots. Even if you do cut it out, there could be other areas in the tree which hadn’t reached maturity to for the fruiting bodies to bloom yet and if you cannot control the environment to remove or control the offending partner then it is likely that having shown susceptibility currently it is at risk in the future. If the tree is worth $$$ or has a high level of sentimental value then it would seem wise to put the time in to control it.
Certainly Ryan thinks that rust can be controlled and junipers and at risk deciduous can live side by side. He has produced featured content on the life cycle and control. https://live.bonsaimirai.com/library/video/understanding-rust
The video was summarised in another thread on the forum
After posting the photo of my juniper above with the generalised infection earlier this spring, it was bagged immediately when I found it the day the fungus appeared, the day before it had looked completely normal. Now this weekend I have identified that even though we have had only a few hours of rain in the last 8 weeks, 6 out of 9 of my hawthorns in various stages of development are showing signs of small rust spots on multiple leaves along with the hawthorns on a 6 metre stretch of hedge on the border of my property (I have 50-100 hawthorns in the hedging around my property and half a dozen apple, crabapple trees in my garden and a quite a few other susceptible trees in collection). I am lucky that I am not too fussed about junipers and other than a few nursery stock converts, I see the juniper as being the weak link in the chain and the hawthorns are where the value is to me and I realise the pathogen is endemic to my environment.
This evening I was plucking off infected leave and giving them all a spray with Fungus Fighter. One hawthorn which is particularly early in its development and low value to me was showing a 20-30% infection of foliage, I bagged and threw out. I haven’t decide what to do with the hedge (if anything) as this stretch has at least a few sets of nesting birds, so I can’t cut back the foliage or spray it yet. My XL yamadori hawthorn has quite a large number of leaves showing infection, but it is too big to search through the foliage and cut of the infected leaves so it has had an initial treatment with fungus fighter and I will carefully watch this one.
At this point I see this as a learning opportunity.
There is no cure for this fungus cycle.
But it is perhaps possible to break the yearly cycle, by treating the crabapple tree with horticulture oil in the fall, then again in March followed by a copper fungicide in April for my area in the Northeast.
It is an opportunity to learn, I can cut my crabapple down if necessary but I will try this to see if it will prevent the rust from forming.
For this year I cut off the effected part, blasted it with neem max, FXi and then a copper fungicide since I was treating the crabapple and had it all mixed up.
If treating the crabapple will reduce or prevent the cycle from completing it is worth keeping the crabapple.
If not the crabapple goes first, then the affected bonsai.
What I find interesting is it never happened until I brought Eastern Red Cedars on the property, but the procumbens was the one that was effected.
It is curious, did the fungal spores from the cedar, land on the procumbens?
Then that cycle completed on that tree?
All very interesting to me.
Worse case is it doesn’t work and the crabapple get removed in the future or I get rid of the eastern red cedar bonsai as they are the trees that carry the spires that interact with the crabapple.
Appreciate the insights on this thread. Really great to get soe much details about your experiences and point of view about how to resolve.
I live in an area that is surrounded by wild hawthorne trees, so there’s no way that I’ll be able to reduce the transmission. For the time being I’m going to keep the tree but try to be more vigilant about getting copper fungicide spray at the right time.
I’ll return to this thread next season and share if this tree is presenting any symptoms.
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So does Hawthorn cause the same issues on juniper?
Or with a different species of tree?
Which two trees are involved in the cycle?
Thanks !
Gymnosporangium globosum, AKA Hawthorn Cedar Rust and Gymnosporangium juniperivirginianae, AKA Apple Cedar Rust are different fungal diseases but very similar in behaviour and appearance. They both jump between juniper and rosaceous plants. But with subtle differences in species.
Gymnosporangium globosum
Rosaceous plants - Crataegus species, as well as apple, crabapple, pear, and serviceberry.
Juniper - primarily affects eastern red cedar, Rocky Mountain juniper, southern red cedar, common and prostrate junipers
Gymnosporangium juniperivirginianae
Juniper - Eastern red cedar (Juniperus virginiana). Other juniper species, such as Rocky Mountain juniper (J. scopulorum), and some cultivars of Juniperus chinensis can also be affected. Some other juniper species like Juniperus communis f. oblonga may also be susceptible,
Apple family (Rosaceae) - Apple A major host for the fungus, especially in North America. Crabapple, Hawthorn (Crataegus spp - can be affected, but another, closely related species of Gymnosporangium is often the cause of the rust on hawthorn.) Pear, Quince (can be affected, also by a different Gymnosporangium species) Other plants in the apple family can also be susceptible, depending on the specific Gymnosporangium species involved.
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