I am looking for advice on pruning young hybrid plum trees. I have a 40+ trees that have been in the ground three years. On a few trees, one or more strong branches from just above the graft union have vigorously shot up in the past year and reached 75% of the height of the main trunk, while the main trunk has had modest to low growth. Is it ever smart to select these vigorous branches to replace the main trunk, or if the tree were adequately pruned the vigor on the main trunk would be as high?
This is how I do it.During planting,usually there are small branches along the trunk.3 or 4 of them are selected,they can be low or high,but more important is the vertical spacing between them,the farther apart is better and pointing away from each other around the tree…Also the crotch angle’s should be near 45 degrees,if possible.If they are fairly long,their length is reduced about 1/3.Then everything is cut off above the highest chosen one.
With the tree in your photo,I might pick about 4 of those branches,assuming they are not the root stock,cut them back about halfway and remove everything else,including the main trunk.Basically like I described above.
Interesting. I assumed it was better to maintain a single trunk for a couple feet before opening up the center.
The shoots are almost certainly your rootstock so you need to remove that growth. If you are not sure you can compare the foliage in the spring.
They are above the graft union, ie not the rootstock.
Well, with 40+ trees I guess you could try a handful of different approaches. One of them is bound to be the best 
They will probably all work to one degree or another. If rabbits chew on the bark it might be harder to protect a bunch of lower/ground level branches as opposed to just putting one spiral guard on the main trunk.
What varieties of hybrid plums are you growing? Is there one particular variety that is sending out those lower branches?
I’m growing Alderman, Underwood, Black Ice, Kahinta, Kuban, Toka, Superior, Shiro, Opal, Santa Rosa, and RF98-95-17-7, a plum from the same breeding program as Black Ice, I believe.
The pic is a bit deceiving as 6" of the base of the tree are hidden by the grass. Each of these shoots is off of the graft.
Good choice with Kahinta. It is probably not as well known as the others, but for me it has been vigorous, a reliable bearer and tasty.
That might have been available three years ago.
I guess all those low shoots can be removed and see if more grow on the trunk up higher.
Yeah, what I had in mind in my original question was whether it was better to eliminate the old trunk since the vigor seems to have moved elsewhere in favor of a younger more vigorous sprout (but also I don’t know enough about plums yet to know if that’s how it works: if the trunk has lost vigor compared to elsewhere in the tree, has it lost it for good, or will proper pruning return energy there).
But thanks for the advice, I might experiment with a couple of trees, and include opening up the vase like form of the tree from the base as you suggest, and on others where it seems to make more sense, select a strong upright shoot to replace the trunk.
That is what I do. I don’t go open center until plums are already bearing for a while, and maintain a central leader for as long as it is practical- especially for Euro plums. I also train to develop a trunk free of branches for the first five feet so I can install baffles to ward off squirrels and coons.
The central leader allows easy use of spreaders to train scaffolds, although that isn’t such a problem in smaller orchards where you can easily take time to tie down branches with stakes and strings if it doesn’t impede mowing too much.
I often maintain a central leader for peaches until the 4th or 5th year as well, but summer pruning may be needed to sustain good wood on lower permanent scaffolds.
That said, I’ve never seen research to demonstrate which method leads to earliest and best productivity, but it is easy to develop strong scaffolds if you maintain a central leader for a while and eliminate oversized ones that have more than half the diameter of the trunk where they join it.
As far as losing vigor, maybe you should stop making trees compete so much with turf as appears in the photos.
Thanks. I definitely need to get the turf under control. Applying cardboard and 1/2 yard of mulch per tree currently because I often don’t have time to mow and want to avoid herbicides.
Interested in your input because we have plenty of raccoons at the wood’s edge and neighbors who feed them. What do your raccoon baffles look like?
Impressive. What are the two materials you’re using? They look semi -rigid.
I was going to write out a bit of an explanation, but my son called. Here are the details. The metal is aluminum flashing (AKA roofing coil) stapled directly onto the trunks of trees working up. We use thicker prepainted stuff for at least the bottom 24 inches (minus the overlap). The thinner, cheaper stuff comes in 20" rolls and unpainted but we spray paint it for cosmetic purposes even though it makes it easier for squirrels to climb by providing some traction. However, on the estates these orchards exist aesthetics are important.
To keep the cylinders slick enough we use a mixture of axle grease and motor oil that has to be reapplied about twice during the season with a wide paint brush. At some sites the pressure is so intense that the cylinder needs to begin right at ground level and at at thicker diameter than the trunk of young trees because a narrow poll is easier to muscle up than a wide one.
At some sites 5’ above the ground is enough- at other sites they leap a bit over 6’ to defeat a baffle. Of course, their level of hunger and determination varies from year to year but if I build a cylinder form the ground that goes up 6.5’ and keep it slick I will never lose the crop to squirrels in my experience.
