Red maple is mentioned as being toxic to blueberry shrubs, along with black walnut, beech, and sunflower. However, we made compost from maple leaves, Norway maple, for many years, and used this material to amend our sticky clay soil when planting blueberry shrubs. The shrubs grew well, and turned out looking just the same as shrubs that were grown in soil amended with peat moss.

Should be fine if it's aged a bit. Pine is over rated for acidifying qualities, I think.

Conifers typically have more lignin in their bark, which means they'll take longer to break down. Other bark is probably fine, but the medium will break down a little quicker.

In the ground, that's probably not a problem. In a container, it might be.

From what I have read hardwood bark is generally not recommended for blues. I would stick with what's proven, pine, fir, and peat.

RM

I also produce lot's of hardwood bark from firewood. I even had bark breakdown on my firewood. A great compost. I use it as mulch, but not for blueberries. I agree with riverman1 I would not use it.

I have mulched blueberry shrubs with shredded cypress bark, and also with arbor vitae leaves. However, these materials were used as mulch, and not as a soil amendment.

A supplement is not the same, necessarily as an amendment. I wouldn't mix any fresh raw wood product with the soil, but if it's spread on the surface like a mulch I think it will be fine. I believe pine fines are aged before being used in a potting mix.

Mixed in the soil I would think any fresh bark would suck out the N. for a period of time- I also believe that blueberries don't care where the organic matter in the soil comes from as long as you manage the pH.

You can't assume that what is needed to create potting soil will carry into what is needed in a general soil mix, where the soil itself dominates and you don't have the drainage confinement of a pot.

Anytime you mix materials with a high carbon to nitrogen ratio to the soil where the carbon is easily available you will likely have difficulty keeping enough N in the soil for you plants.

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Here is a link that might be useful: C-N ratios of various raw materials.