Pruning japanese hybrid plums

I have 20+ Japanese hybrid plums planted last spring and this fall at 15’ spacing. My research has lead me to believe I should prune plums to an open center but I’m wondering if this is advisable based on people’s experiences growing on p. Americana in a 5b climate.

List of varieties,

Alderman
La Crescent
Underwood
Brookgold
Prunus nigra
Prunus americana
Toka
Superior
South Dakota
Tecumseh
Brookred
Valton

Early golden
Shiro
Elephant heart
Burbank

Any suggestions would be appreciated.

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I don’t begin training them to an open center myself- I maintain a central leader for several years- the trunk allows me to use spreaders effectively or to use lower branches to tie eventual permanent upper branches with string.

Eventually I will cut out the center to allow maximum air and light penetration for 3-4 permanent scaffolds. There isn’t the same hurry to do this as with peaches, because shading of interior wood in peaches can make the interior of scaffolds permanently barren.

Nevertheless, I usually start my peaches as central leader trees but it requires summer pruning to stop that from happening.

I also suggest you include Reema and Early Magic to your collection.

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Alan,

A few of thebplums I planted were whips this fall and quite long (4-5’) range. Would you suggest heading back the whip to encourage lateral growth lower on the trunk? I suspect I may have a problem with scaffold branches starting too high up.

Also what do you recommend for spacing between scaffold branches? It seems the ones I planted last year have all come within 12" of each other which seems reasonable as long at they Arnt moving in the same direction.

Thanks

It depends. At sites I manage I often need to construct squirrel baffles and keep fruit pretty high to discourage deer. I like at least 4’ of trunk before first scaffolds. If these aren’t issues where you are it is a good strategy to cut back whips to a bit above where you want to develop permanent scaffolds.

I recommend waiting to choose permanent branches because plums often are not cooperative in producing secondary branches off of scaffolds, shoots are often excessively vigorous and upright, so some extra branches provide a site to tape them to. You can remove secondary branches (shoots) from temporary branches and just use them as a scaffolding for training purposes.

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You going to have a bunch of fruit in a few years!
I have a number of the same varieties as you, most have been in the ground for around 8 years. I just let them grow for the first few, minimal pruning or training until they started bearing besides removing sprouts that were too low (below 4’), crossing or inward growing branches. One complicating factor is that different varieties have much different growth habits and vigor.Some of the more vigorous and lanky ones might have benefitted from some early heading cuts(LaCrescent, Toka). Others are pretty much self-training(Superior, Underwood). I have gradually pruned the center leader out of the vigorous ones. One you should consider adding in is Purple Heart, it is the best tasting out of the ones I grow.

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@Caleb → Nice list of hybrids. Where did you get your Prunus Nigra from? Is it the “Bounty” variety, or a pure Prunus Nigra?

100% Agree.

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Alan,

Deer were extirpated from my island years ago so im lucky in that regard. I guess its safe to start scaffold lower than, eh? Our winters are hit or miss but sometimes we can get ridiculous amounts of snow which may or may not make difference as well.

Ztom,

The nursery i purchased it from states the following,

“This wild plum tree is native to Canada and will pollinate American and Asian plum trees. The small fruit are delicious if left to ripen fully on the tree. Ideal for jams and jellies too. They are impressive to look at when in bloom.”

It may be worth asking where they source the seeds and if they can guarantee the parents were both wild. or perhaps they graft wild scions onto on P.Americana?? Ill have to look closer to see if there is a graft union.

Jesse,

Thats the hope! I have been discouraged from growing plums from neighbors due to a severe black knot problem in my area. However, most people around here were growing old European varieties, of which were all highly susceptible to the disease.

Im still not sure if they’ll work due the trees tendency to come out of dormancy before frost risk has passed. The site is on a high point a few hundred yards from a large saltwater bay…Ill keep my fingers crossed!

Ill have to keep a look out for purple heart. Up here in Canada we dont have as many nurserys, eh. Unless you want to smuggle some scions across the border for me!

Prunus Nigra can be hard to find online, and I’m not sure why. Maybe low demand? Prunus Americana is easy to find for sale. I bought Prunus Nigra from Forest Farm years ago but it has been replaced in their catalog by “Bounty” which may be suspect as a pollinator. I hope I got the original but all the fruit has been hit by PC and falls early so I haven’t been able verify it’s authenticity. Also, I haven’t had black knot on any of my hybrids yet.