Drew,
If the branch is not crossed, mangled, or diseased I leave them alone with my carmine jewel bush cherries. I've not seen any benefit to pruning them and it only results in fruit loss. My north star bears very little fruit but is a natural dwarf at 10' and needs very little pruning. My Joel cherries are not old enough to know yet. When I prune my fruit trees my goal is always to get more fruit long term and to make spraying easier. In the case of bush cherries I don't see the benefit to doing it unless you lived in a climate where disease would be a problem because the tops got to thick preventing spray from reaching everything. My carmine jewel have never thickened up like that but if and when they do I will just take out every other branch.

Yeah I'm not sure as other cherries sweet or tart are pruned for various reasons. These are a lot different.
The Mesabi cherry is somewhere between a bush and a normal form, yet adding even more mystery to pruning.

This post was edited by Drew51 on Sun, Dec 21, 14 at 17:55

I believe there are a few notes in the below link about pruning. From what ive read you just want to do as little pruning as possible, yet creating good airflow. What I understand is that many people talk of similarities between pruning bushes like mock orange. IT seems somewhat similar to roses (dead, diseased, crossing, and large older canes cut to the base or ground)

""Rules for pruning and training
1. Do pruning in April before trees break dormancy to encourage growth.
2. Pruning for size reduction should be done shortly after full leaf stage begins. It may
be possible to decrease the size of the EvanâÂÂs Cherry with this method.
3. Never do pruning in summer or fall, it would encourage late growth and increase
chances of winter damage.
4. Remove branches that rub against each other and diseased or damaged wood.
5. DonâÂÂt remove more than 25% of the wood in any one year. To remove more wood
may encourage vegetative buds and reduce fruit yield the following year. Keep the
branches thinned so that at harvest time you will have enough room to reach your fruit. 6. Allow your tree to have weeping branches. The branches weep because they were
weighed down with fruit and are more likely to produce fruit in the future.
7. SK Carmen Jewel should be trained as a tall bush, similar to the way Saskatoons are
grown. Although more research is needed on this, probably an open centered, vase
like bush would be ideal.
8. EvanâÂÂs Cherry should be trained with a single trunk. Training to an open centre
would make fruit more accessible at harvest.
9. Prunus eminens (or Mongolian cherry per catalogues) can be grown and clipped just
like a hedge but this method will not produce much fruit. Thinning is needed to ensure
enough light for fruit development. If you can still see some light coming through your
bushes when in full leaf, then you have pruned enough.
""

Here is a link that might be useful: u of sask

Thanks much, my biggest question was to being open centured or not. it makes sense to do that. To let light in. Although it appears the jury is still out.
Also just a note MSU determined that summer pruning is OK if done before August 1st. They suggest this for sweet cherries, that it is the best pruning time. Not sure on tarts? That is for here, zones 5 and 6.

I have a Carmine jewel and a Juliette, both planted last year. I believe you remember my post about pruning that one? Looked like a 2 foot mini tree. The Juliette, is very low, and very bushy, and about a foot tall now. Neither grew much, but im expecting good things next year. No pruning this year :) Also have 4 year old evans plugs. One needs some good pruning.

I usually stick to the U of Sask for info on these cherries. They are the original breeders, and are very open with information regarding care and breeding. But you are right, they are still experimenting. Sounds like an excuse to get a few more and experiment youself.

As for when to prune? I just use information as a baseline for my own area and just put two and two together for timing. Only took me two or three seasons. Here all my trees get pruned and grafted at the same time, and beause of the way the climate is, they also tend to flower at relatively the same time. The information i linked is based out of saskatoon, which get average lows of -35 and -40C, and has a much shorter growing season than you, or even me. Just keep in mind theyre cherries, and too much green growth in fall can cause dieback.

For us at August 1st we have 3 more months or more of frost free weather. Here in the spring it's wet, and fungal infections are bad. So MSU feels it's better to wait till the dry summer. Still suggests you spray copper before and after pruning. MSU also says you can prune in the spring, just wait till it is dry. Most times you need to prune in the spring to reduce terminal flower buds on sweet cherries.

My Carmine Jewel last summer grew very little...i probably wouldn't touch them until they have put on a lot of growth. Even then i'd limit pruning.

I think you're right Frank. Mine only grew a few inches the first year. I moved them from my cottage to the city and put them in pots. I was afraid they would die at the cottage. I have no place to put them though, so they went in pots, two Carmine Jewels. My Crimson Passion, Romeo, and Cupid died at my cottage. These lived. They grew a good 2 feet in the pots, and are now three feet tall. I'm glad I moved them last year. Amazing growth here. So i will lightly head back a few branches now, Maybe open the center up too. They grew a lot, so can be pruned now. I may wait another year to open center. Maybe just do one and compare to the other. See what happens.

Drew,
I wonder why your cherry bushes at your cottage died. Were they protected from rabbits and deer? Were they choked out by weeds or too shaded? Poorly drained? They are supposed to be pretty tough plants. My Carmine Jewels have survived drought and bitter winter cold just fine. Northwoodswis

Poorly drained soil. We had a wet spring, wetter than normal. The Carmine Jewel plants though survived it. The toughest of them IMHO. I'm bummed as we still cannot get Cupid here. I should have never tried. It works out as two Carmine Jewel's are fine for me now. I don't expect fruit next year, still small, but in 2 years for sure. They sort of lost a whole year up there. I have managed to grow Cornus Mas up there in those conditions, hardly anything else. Well currants, elderberries, thimbleberry, and wineberry. I do have some high spots, now all taken. It is low light there too. I have one spot that is high, and has good light. A Glacier sweet Cherry tree is there, but it has canker.
I'm not going to grow much else up there. I do have another lot, but it too is low and currently is wild. I would have to fill it and remove the wild foliage. I may one day. It has full sun there. I could grow a lot there.