Fertilizing Shimpaku junipers

[Mailman17013]

Any advice for fertilizing shimpaku junipers? Do they prefer an acidic fertilizer like Miracid or is something like Green Dream preferable?

 

[Bonsai Nut]

A lot depends on where you live, and the quality of your water. Junipers in general prefer acidic soil conditions. Most municipalities treat their water to be alkaline because it prevents pipe and equipment corrosion... but it is very hard on plants.

If you live in the NE, your rain tends to be more acidic than other parts of the country... though there have been a lot of pollution control changes implemented that have reduced the degree to which this occurs. So generally speaking, if you live in a rainy part of the country and your trees get a lot of rainwater, acid fertilizer will be less necessary than if you live in a part of the country where you rely on a lot of irrigated water.

 

[Shibui]

We don't have the problem of alkaline water so all my trees, including juniper, get standard fertilisers.

 

[Japonicus]

Please see page 12....
http://alabamabonsaisociety.org/blog/wp-content/uploads/2012/04/The-Shimpaku-Juniper.pdf
My shimpaku is the only conifer I withhold “MirAcid” on, since its origin is largely limestone .
I’m sure it can evolve to accept some and now and then should not damage a strong plant
but it gets left out of my rotation.

 

[Mailman17013]

Japonicus, I have heard that they do not like a MirAcid or acidic based fertilizer. This was the main reason for my question. Just looking for confirmation on this. Thanks for your input, much appreciated.

 

[Bonsai Nut]

Japonicus, I have heard that they do not like a MirAcid or acidic based fertilizer. This was the main reason for my question. Just looking for confirmation on this.

Did you read / understand what I wrote?

Not only do junipers prefer acidic soil, but they actually CAUSE soil acidity. In the presence of limestone, this affect is offset, but that doesn't mean it doesn't occur. Junipers can tolerate a wide range of soil conditions... but just because they can tolerate them doesn't mean that is where they do best. But without knowing your water pH and your soil pH you have no way of knowing whether you should use Miracid or not.

 

[Bonsai Nut]

Please see page 12....
http://alabamabonsaisociety.org/blog/wp-content/uploads/2012/04/The-Shimpaku-Juniper.pdf
My shimpaku is the only conifer I withhold “MirAcid” on, since its origin is largely limestone .
I’m sure it can evolve to accept some and now and then should not damage a strong plant
but it gets left out of my rotation.

I think you misunderstand what that PDF is saying. In the presence of limestone soils, a conifer's impact on increasing acidity is offset. Limestone soils will remain more alkaline. If you take a wild collected tree from an area of alkaline soil, and transplant it into an acidic soil mix, the tree will struggle in the short term - probably regardless of species. I collect junipers from the desert where this impact is well-known - it is a quick way to kill an already stressed tree.

I have no idea what pH your soil is, or for that matter how much rain you use, or the pH of any irrigation water you use. THAT is what determines whether or not you should use acid fertilizer. I own over 50 shimpakus, as well as numerous other types of junipers, however what works for me may not work for you because of this reason. Likewise... what works for trees in nature may not work for a cultivated tree, 100 years later, in a container.

I use acid fertilizer on my junipers because our irrigation water can be as high as 8.5 pH, and my target goal is to keep their soil pH in the 6.0 - 7.0 range where they do best. If your soil is already there, and your irrigation water is neutral or only slightly alkaline, and you get a fair amount of rain, you probably don't need to use acid fertilizer.

 

[BonsaiMatt]

I think you misunderstand what that PDF is saying. In the presence of limestone soils, a conifer's impact on increasing acidity is offset. Limestone soils will remain more alkaline. If you take a wild collected tree from an area of alkaline soil, and transplant it into an acidic soil mix, the tree will struggle in the short term - probably regardless of species. I collect junipers from the desert where this impact is well-known - it is a quick way to kill an already stressed tree.

I have no idea what pH your soil is, or for that matter how much rain you use, or the pH of any irrigation water you use. THAT is what determines whether or not you should use acid fertilizer. I own over 50 shimpakus, as well as numerous other types of junipers. However what works for me may not work for you. Likewise... what works for trees in nature may not work for a cultivated tree, 100 years later, in a container.

I recall you mentioning that you use acid fert to compensate for your tap pH. I also have city water at around 8 pH. I am thinking about trying a more acidic fert ball/teabag mix. I am trying to find out if this is needed: Have you measured your runoff pH before vs after the acid regime? Curious if your acid regime is measurable in your runoff.

 

[Japonicus]

I think you misunderstand what that PDF is saying. In the presence of limestone soils, a conifer's impact on increasing acidity is offset. Limestone soils will remain more alkaline. If you take a wild collected tree from an area of alkaline soil, and transplant it into an acidic soil mix, the tree will struggle in the short term - probably regardless of species. I collect junipers from the desert where this impact is well-known - it is a quick way to kill an already stressed tree.

I have no idea what pH your soil is, or for that matter how much rain you use, or the pH of any irrigation water you use. THAT is what determines whether or not you should use acid fertilizer. I own over 50 shimpakus, as well as numerous other types of junipers. However what works for me may not work for you because of this reason. Likewise... what works for trees in nature may not work for a cultivated tree, 100 years later, in a container.

You’re right. Also, the shimpaku we use, unless imported from such as the pdf are cuttings or layered for
the most part I have to presume. That means they were not collected in a limestone region and have already
adapted, true that. I just withhold it based on the original origin. My tap water in Neutral.
I have not checked run off pH from my shimpakus waterings.
I’ve used MirAcid on mine before I learnt the origin with no ill effects.
I should check my shimpaku run off for pH is that correct?
I don’t test or count rain water as my tap washes that out as a standard more often.
Oh, I also omit Holly Tone on mine substituting Plant Tone. Same idea I know

 

[Bonsai Nut]

I recall you mentioning that you use acid fert to compensate for your tap pH. I also have city water at around 8 pH. I am thinking about trying a more acidic fert ball/teabag mix. I am trying to find out if this is needed: Have you measured your runoff pH before vs after the acid regime? Curious if your acid regime is measurable in your runoff.

It is very definitely measurable. I try to be as consistent as possible and use the same amount of acid fertilizer, each month, per tree, but the soil pH fluctuates. In months when we are getting a lot of rain, I don't use it. Also, our water pH changes during the year. In the winter it is about 8.0 and in the summer it is higher - about 8.5. That's why I say I try to keep the pH in the 6.0 - 7.0 range. I was initially worried that swings in pH were going to harm the tree, but I haven't noticed any negative impact. If you are concerned I would just start with a lower application rate and work up from there. I also don't use it on newly repotted trees.

 

[BonsaiMatt]

It is very definitely measurable. I try to be as consistent as possible and use the same amount of acid fertilizer, each month, per tree, but the soil pH fluctuates. In months when we are getting a lot of rain, I don't use it. Also, our water pH changes during the year. In the winter it is about 8.0 and in the summer it is higher - about 8.5. That's why I say I try to keep the pH in the 6.0 - 7.0 range. I was initially worried that swings in pH were going to harm the tree, but I haven't noticed any negative impact. If you are concerned I would just start with a lower application rate and work up from there.

Thanks, I'm hesitant to start testing runoff and chasing pH... Worried it'll be Pandora's can of worms or something lol.
My plan is to switch to hollytone from plant tone in my Tea bags... If the runoff calls for it.

 

[Bonsai Nut]

Thanks, I'm hesitant to start testing runoff and chasing pH... Worried it'll be Pandora's can of worms or something lol.
My plan is to switch to hollytone from plant tone in my Tea bags... If the runoff calls for it.

I am not one to chase soil pH just for the fun of it. I was keeping my junipers alive before I started using it. But the difference is remarkable (for me, in my area with my bad water), both in terms of coloration and tightness of the foliage. Rather than rely on testing methodologies, get your hands on a bunch of shimpaku whips (you can usually find them for a few dollars each). Separate into two groups - treat both groups exactly the same with the exception that one group treat with acid fertilizer. Take pre and post photos and share your results If your soil pH is already good (6.0 or so) there probably won't be much of a difference. If your soil pH is higher than that you probably will see a difference - if not a remarkable difference. Remember - if your soil pH is above neutral, it becomes progressively more difficult for trees to take up certain elements - particularly iron and manganese. You can use all the iron fertilizer in the world, and if your soil pH is too high, you can still find yourself with pale/yellowing foliage due to iron chlorosis.



Just going to add... I started using acid when I was having problems with chlorosis in my adult citrus trees. I spoke to some professional nurserymen who told me that you will be unable to keep citrus healthy in Orange County if you don't use acid (in the form of elemental sulfur). Then at Southern California bonsai shows I would talk to owners whose junipers looked so much healthier than mine - and a common theme was iron and acid.

 

[BonsaiMatt]

unable to keep citrus healthy in Orange County

Kinda ironic lol.

Great info as always!
If I run a test i will be sure to document and share.
My masters research was all about Oak trees so I'm no stranger to torturing trees in the name of science ?

 

[Bonsai Nut]

Kinda ironic lol.

Maybe it was different in the past, because maybe the water was different(?) All I know is that you can still find orchards of dark green beautiful citrus here... but it's because of the sulfur (or other acidifying product).

Speaking of acidic soils... how about them white oaks!

 

[BonsaiMatt]

Don't get me started on oaks lol. White Oak was one of the species I studied, along with post Oak, live Oak, and chinkapin Oak. I was focusing on above-ground chemistry, so other than soil moisture, I ignored most soil parameters.

 

[Bonsai Nut]

Don't get me started on oaks lol. White Oak was one of the species I studied, along with post Oak, live Oak, and chinkapin Oak. I was focusing on above-ground chemistry, so other than soil moisture, I ignored most soil parameters.

Any work with Valley oaks? They aren't an east coast species, but I'm starting to mess around with them and really like them. Same soft lobed leaves as white oak, and deciduous, but I can at least keep them alive down here. Tallest oak in the US is a Valley oak - they are growers!

 

[Japonicus]

View attachment 240238

That's a beautiful view and capture

 

[Ali Raza]

Any work with Valley oaks? They aren't an east coast species, but I'm starting to mess around with them and really like them. Same soft lobed leaves as white oak, and deciduous, but I can at least keep them alive down here. Tallest oak in the US is a Valley oak - they are growers!

View attachment 240238

Now that is called PARADISE

 

[Bolero]

every other week...good soaking.

 

[BonsaiMatt]

Any work with Valley oaks? They aren't an east coast species, but I'm starting to mess around with them and really like them. Same soft lobed leaves as white oak, and deciduous, but I can at least keep them alive down here. Tallest oak in the US is a Valley oak - they are growers!

View attachment 240238

Nope, I had never heard of them until Brent mentioned them a while back. Very limited natural range. Have you grown them in containers?