New to Bonsai - Infected Bonsai with Root Rot (Case Study)

[MatthewMacKay]

Hi All!

I'm quite new to the hobby (and forum) and recently bought a tree that has run into some problems. I thought it may be beneficial to work through this case to see what mistakes I might have made as a beginner, and what can be learnt from this scenario.


I bought the bonsai back in April prior to winter here (Australia) but didn't check the health of the tree (big mistake), which it already had some black 'mouldy' spots on the deadwood. Being new to bonsai, I thought this might just be mould from water not drying out on the deadwood, so I monitored the soil dampness until winter. It rained a fair bit when winter came, so I adjusted the watering schedule to essentially once per week since the soil was already retaining a lot of water - if the soil felt wet, I wasn't giving it more water.

Fast forward to 2 weeks ago after a lot of rain, I noticed the live vein was extremely damp, almost mushy in texture, and the bark was peeling off. The black mouldy spots had spread, and I realised this might be a ?fungal infection. This was the moment I knew something was wrong, and I suspected the soil might be retaining too much water and the tree was at risk of root rot/further infection. We were a month into winter, and I know repotting isn't ideal during winter as the roots are at risk of being damaged by the cold, but I felt the soil was too compacted to leave alone outside in the rain - considering I don't have a greenhouse. I decided to take the bonsai inside and investigate the root system and soil. As expected, it was pot bound, the roots had no room to breathe, and the soil was compacted. Some of the roots were starting to get soft/rotten, so I cut them out.

This is where I think I made my biggest mistake, and should have acted sooner. I left the bonsai indoors to dry out, which even after 4-5 days the soil was still wet. I was concerned about leaving it outdoors in the cold and rain as it was already taking a long time to dry out. I feel that the health of the tree significantly suffered given the lack of sunlight, and should have invested in a way to give the tree light without exposing it to rain. After the 4-5 days the tips started to go brown, I panicked, made up a mostly inorganic/well draining substrate (scoria), put it in a pond basket for better aeration, and put it outside to get some sunlight. I've been monitoring it 2 times a day to see if it needs water, and it almost certainly does every day with the scoria. I've worked some 3-6mm pine bark into the mix to give it some more organic substrate, and I've treated the tree with around 1:50 diluted lime sulphur spray and then lime sulphur neat to treat the black spots on the deadwood.

The tree seems stable, but I honestly don't know for sure. I suspect the tips are still browning but very very slowly, I've got some photos to show the extent of the browning. I guess the main question is, after all of this, am I overreacting and the tree is probably fine?

Matt

 

[The Barber]

Those brownish tips are male cones, it is how they reproduce.

If deadwood isn't preserved it will grow mold and decay.

Where are you located? Might want to update that.

I think you are most likely overreacting.

 

[rockm]

Keep overcaring for it and it will die. Quite trying to "do" something. Keeping it inside was/is a mistake. If you're concerned about rain, put in in a location outside that is sheltered from the rain--like under the overhang of a roof. You can even spread a piece of plastic over the soil surface when it rains. As for cold, if you're in Australia, cold isn't a concern for a juniper. Unless i gets down to 25 or 20 F (-3 to -6 C) or lower, there's really no cause for concern. Even at those temps, there's really no danger if the tree is out of the wind and placed on the ground. If you have stretch of weather with SUSTAINED temps at -3 or below -- like five days or more, then you may run into issues.

You've already messed with it enough. Let it alone. Make sure it doesn't dry out (BTW adding organic material isn't a great thing to do, since junipers prefer free-draining soil). Not a huge deal though).

 

[shohin_branches]

The foliage and roots look healthy. Let it grow and observe what the plant is doing throughout the year. Observation is an important part of learning a new plant species and understanding it's growth patterns and cycles.

 

[Shibui]

From what I can see - and hear in the post - you are definitely overreacting and have done so from the start.
A beginner diagnosing complicated problems? and then applying questionable cures for a problem that might not be???

As for cold, if you're in Australia, cold isn't a concern for a juniper. Unless i gets down to 25 or 20 F (-3 to -6 C) or lower, there's really no cause for concern.

There is nowhere in Australia where winter is too cold for juniper bonsai. We have a couple of bonsai growers in the few alpine cold alpine areas who keep juniper (and most other temperate species) outside all year round.

Advice to leave it alone is very sound. The pictures show no real evidence of any problem yet though we won't see the results of your interventions for several months at this time of year.

Definitely add a location to your profile. Australia is a bloody big place with many different climate zones so advice that's great for one place will not always work somewhere different. Without a more specific location you can't get really good help.

 

[leatherback]

What I can see from the pictures, there is/was absolutely nothing wrong with that tree

 

[MatthewMacKay]

Hi All!

Thank you for your feedback.

General take home messages across all the responses:

1. Bonsai are more robust than I previously thought.

2. It is very likely the deadwood was not treated this year prior to purchase. Hence the mould.

3. Good idea to setup a way to reduce rain exposure while outside, either by greenhouse or plastic sheet (providing good drainage) - I would assume the plastic sheet would retain the moisture if the pot isn’t draining - this was my case.

4. Australian temperatures are generally not a problem for the roots, I’m based in Sydney and sub zero is extremely rare.

5. Interestingly, I have trees that look less healthy than this tree I showed, but I’m not concerned because I haven’t done anything to them other than water. I can see the source of concern was just doing a repot for the first time on a tree that was probably experiencing a bit of root rot.

As a side question, if anyone wants to jump in, the way I identified the root rot was by handling a few thicker roots that simply disintegrated, I barely touched them and they had no strength/structure. Could there be another explanation for this other than root rot?

Matt

 

[Deep Sea Diver]

Hi All!

Thank you for your feedback.

5. Interestingly, I have trees that look less healthy than this tree I showed, but I’m not concerned because I haven’t done anything to them other than water. I can see the source of concern was just doing a repot for the first time on a tree that was probably experiencing a bit of root rot.

Yep, I concur. Looks like a normal Juniper ready to be repotted. In our experience here once one can see a tree has root rot, there is little they can do to save it.

As a side question, if anyone wants to jump in, the way I identified the root rot was by handling a few thicker roots that simply disintegrated, I barely touched them and they had no strength/structure. Could there be another explanation for this other than root rot?

Matt

Roots can die in the pot simply due to overcrowding. Your description of the root ball bereft of O2/H2O exchange is very similar to two heritage junipers we repotted years ago. Chock full of roots, some long gone. These were also larger roots.

Besides repotting this tree properly and getting it on a schedule... as well as your other trees..... Something that can be done to help improve the O2/H2O exchange in the media during periods of consistant rain... is to raise the effective perched water layer (Media can't hold as much water). Do this by chocking the tree up with a piece of wood or stone on one side.

Additionally use a ceramic drill to put holes in the "four sides" of the pot near the pot wall. This action creates holes water can drain out of when the pots are chocked up. This will improve the O2/H2O exchange even more. Its something we regularly do here due to our heavy rainfall during winter and spring.

Cheers
DSD sends

 

[leatherback]

You overworry.

The tree is healthy.
Your tree will NOT be harmed by the weather outside. All mine are out in full weather exposure and I can tell you.. Your weather does not compare in wetness to what I get.

Just ensure it is planted in well draining substrate and stop worrying.
Wood gets little spots and stuff. It is a plant. Do not worry.

 

[rockm]

Hi All!

Thank you for your feedback.

General take home messages across all the responses:

1. Bonsai are more robust than I previously thought.

2. It is very likely the deadwood was not treated this year prior to purchase. Hence the mould.

3. Good idea to setup a way to reduce rain exposure while outside, either by greenhouse or plastic sheet (providing good drainage) - I would assume the plastic sheet would retain the moisture if the pot isn’t draining - this was my case.

4. Australian temperatures are generally not a problem for the roots, I’m based in Sydney and sub zero is extremely rare.

5. Interestingly, I have trees that look less healthy than this tree I showed, but I’m not concerned because I haven’t done anything to them other than water. I can see the source of concern was just doing a repot for the first time on a tree that was probably experiencing a bit of root rot.

As a side question, if anyone wants to jump in, the way I identified the root rot was by handling a few thicker roots that simply disintegrated, I barely touched them and they had no strength/structure. Could there be another explanation for this other than root rot?

Matt

I wouldn't really try to avoid rain. Not necessary, probably beneficial. If it's a prolonged period of rain, just prop one end of the pot up on a rock-the incline increases drainage.

FWIW, bonsai are not hothouse delicate plants. They're the same trees for the most part that are in the ground in your yard. Junipers are extremely tough plants-in the right setting, as in outdoors. Bring a bonsai inside is mostly asking for trouble.