Juniper bonsai is turning yellow during the heat of AZ summer

[BoB_Jr]

This is a juniper bonsai and I was told that they need to be kept outside at all hours of the day. I was also told that they like direct sun for 6 to 7 hours but when I started giving it around 6 hours of direct sun the foliage started to yellow the next day. I then moved it to get less sun but the problem continued. Right now the bonsai is getting between 2 to 4 hours of direct sun in the morning and indirect light for the rest of the day. I try to water whenever it looks dry which is usually one to two times a day. I also started misting the foliage once a day when I can. It is summer in AZ right now and temperatures can reach 115°F on some days. Also thought I should mention right before summer(I don't have any pictures unfortunately) it was the greenest I have ever seen it and seemed to be doing well. This is my first tree and I don't want it to die but I don't know what I am doing wrong any advice or tips would be greatly appreciated.

 

[Brain Treez]

It's planted in what looks like a slab of mud. That kind of dense, organic soil will take a lot longer than you think to dry out. I assume/hope there are some drainage holes in that pot? Junipers are infamous for holding onto their green far after the triggering event that would cause them to lose it. This decline probably started weeks or months ago.

I suspect overwatering coupled with too little sun is what's driving the discoloration. Before you water, really dig your finger down towards the bottom in one of the corners to see how dry the soil really is.

 

[gooeytek]

Agree with the above. You need to add some free-draining substrate to that mix. Fingers crossed it bounces back.

 

[Orion_metalhead]

Immediately moving a tree to full sun, especially in 115 deg heat is a surefire way to get burnt foliage. If yozve had it in a shadier spot for 2 to 4 weeks, Id move it into a more sunny spot now.

The soil is very poor. Juniper prefer to have drier roots so that soil is creating an undesireable envionment. I agree with repotting into a proper bonsai substrate. I actually dont believe you can water the tree enough in the heat because of the soil's inability to drain properly. In your environment you need soil that retains moisture but also allows air movement.

Have you been fertilizing?

When did you get the tree and from where? What were the conditions before moving it into full sun?

 

[Sagebrush]

I have a p. Nana and a chinensis. Last year I had a similar issue in El Paso. Repotted to traing pots with good bonsai soil. Last yr we had 70 days over 100 and many around 110. They were getting cooked. Mid summer I got them under 70% shade cloth. This year they are much better and I got the shade cloth up end of May. Learned you can't keep trees in black plastic nursery containers in direct sun in this climate. Photos are this spring.

 

[BoB_Jr]

It's planted in what looks like a slab of mud. That kind of dense, organic soil will take a lot longer than you think to dry out. I assume/hope there are some drainage holes in that pot? Junipers are infamous for holding onto their green far after the triggering event that would cause them to lose it. This decline probably started weeks or months ago.

I suspect overwatering coupled with too little sun is what's driving the discoloration. Before you water, really dig your finger down towards the bottom in one of the corners to see how dry the soil really is.

Thankyou so much for the advice, yes the pot does have drainage holes. I will make sure to check before watering it from now on.

 

[BoB_Jr]

Immediately moving a tree to full sun, especially in 115 deg heat is a surefire way to get burnt foliage. If yozve had it in a shadier spot for 2 to 4 weeks, Id move it into a more sunny spot now.

The soil is very poor. Juniper prefer to have drier roots so that soil is creating an undesireable envionment. I agree with repotting into a proper bonsai substrate. I actually dont believe you can water the tree enough in the heat because of the soil's inability to drain properly. In your environment you need soil that retains moisture but also allows air movement.

Have you been fertilizing?

When did you get the tree and from where? What were the conditions before moving it into full sun?

Thankyou so much for the info, Yes I have been fertilizing every three or so weeks. I got the tree from a nursery in phoenix about 5 months ago. Before it was actually at a different house that was not as hot and was receiving around 5-6 hours of direct sun and received some indirect sun for the rest of the day. Is there a certain brand or type of bonsai substrate that I should use when I repot it?

 

[BoB_Jr]

I have a p. Nana and a chinensis. Last year I had a similar issue in El Paso. Repotted to traing pots with good bonsai soil. Last yr we had 70 days over 100 and many around 110. They were getting cooked. Mid summer I got them under 70% shade cloth. This year they are much better and I got the shade cloth up end of May. Learned you can't keep trees in black plastic nursery containers in direct sun in this climate. Photos are this spring.

Thankyou for the info what do you use for bonsai soil, I will try to get some shade cloth for it but right now it is under a overhang so it doesn't get much direct light only in early morning.

 

[BoB_Jr]

Agree with the above. You need to add some free-draining substrate to that mix. Fingers crossed it bounces back.

Thankyou I will make sure to repot it using that soil ASAP.

 

[Sagebrush]

Thankyou for the info what do you use for bonsai soil, I will try to get some shade cloth for it but right now it is under a overhang so it doesn't get much direct light only in early morning.

Weigerts standard mix. No place local or closer to get decent soil. The shipping from the east coast is ridiculous. Next time I will source the components and mix it myself.

 

[gooeytek]

Thankyou I will make sure to repot it using that soil ASAP.

In a pinch, you can mix Soil Conditioner (sifted pine bark) and Napa 8822. I think that'll do well in your hot and arid climate.

 

[BoB_Jr]

In a pinch, you can mix Soil Conditioner (sifted pine bark) and Napa 8822. I think that'll do well in your hot and arid climate.

I just got this bonsai soil from a store do you think this will work?

 

[Orion_metalhead]

What do the particles look like?

 

[BoB_Jr]

 

[Deleted member 47471]

The organic features in your last picture looks like the same material in the pot in previous pictures.

Perhaps inorganic would be better. Using pumice + akadama, then, would be good as it drains freely. All my Junipers have thrived even during 100+ F temps in the summer here in VA. Watered twice a day during the hottest days and still twice a day between 85-90+. This includes trees in smaller terra cotta, traditional bonsai pots, original nursery containers (and their organic components/soil).

Definitely looks like water retention in the case of your tree. Best wishes for a repot and ***inorganic*** soil.

 

[rockm]

View attachment 564304

Not an optimal soil for a juniper. Too much organic content and too many extra fine particles. All that will become mud in a couple of months and you will be back where you started (and BTW, summer is not a great time to repot a stressed tree, or even a healthy one).

Organic mixes hang on to a lot of water. Arizona presents some challenges for soil and watering, but an organic-free soil that drains EXTREMELY well is more appropriate in general for junipers.

 

[Orion_metalhead]

You can try.mixing that soil 1:1 with pumice, or perlite for a satisfactory soil for now. I agree with RockM... not the best time for a repot.

 

[BoB_Jr]

So i should wait until summer is over to repot it? And get inorganic soil?what time of year should I re pot it?

What should I do differently right now so it doesn't die before I repot it.

 

[BoB_Jr]

I was going to check if it needed water and I was told to stick my finger a few inches in to make sure it was dry and found there were alot of these white i don't know what under the surface of the dirt. (first picture is of dirt itself)(second is of the thing outside the dirt)(third is a few I found in the dirt) I don't know if these are supposed to be there or not but i figured i would ask. I decided not to water it because some of the dirt under the surface was still damp.

 

[Orion_metalhead]

So i should wait until summer is over to repot it? And get inorganic soil?what time of year should I re pot it?

What should I do differently right now so it doesn't die before I repot it.

Right now, watch your watering, read up on juniper basics here in the subforum.

Junipers like drier conditions. I would wait until the soil is almost dry before watering.