I am new to plum. Last year my Shiro produced 12 fruit so no thinning is needed. Bagging 12 plum is also easy. This year, Shiro produced tons of fruit. I know how to thin apples and peaches. Plum is smaller fruit. I am sure I can leave more plums on than I do peaches or apples.
Just wonder what a rule of thumb you use when you thin plums. Thanks.
mamuang
I thinned mine every 3 to 4 inches per fruit and that worked out Ok. No broken branches but I have seen people thinned less but then smaller fruits.
Tony
Personally, I don’t thin plums. Most plum trees will naturally thin themselves,
which means you need to pick up the fallen fruit, in case some of the fruit has
pc larvae in them and also to maintain good orchard hygiene.
Some plums thin themselves, but Shiro produces far too many. I don’t have the time to thin it the right way so I just shake the limbs as hard as I can. When the fruits are quarter sized you can get a lot to fall off that way.
Thank you Tony, Rayrose and Scott.
Like Scott said, Shiro oversets. I planted Shiro and Satsuma in the spring of 2012. Both bloomed in 2014 at the same time. Shiro set a few fruit, Satsuma none.
This year, Shiro sets thousands, Shiro sets under 10. For Satsuma, I will follow Rayrose’s advice.
For Shiro, I will thin. Tony’s method sounds good but Scott’s sounds more fun. Maybe, my daughter would like to do for me 
.
I thin all my plums if they over set. Thinning the way Scott does will shake off your heaviest, largest fruit IMO- I use that method with young peaches when I don’t want any fruit.
If you don’t have time to thin the whole tree, thin a scaffold. Of course, you can only do what you can do within your own schedule and one can always do more with fruit trees.
My sun isn’t as strong as it is further south and the fruit is greatly improved in sugar with thinning here. How much depends on the variety, I thin Shiro quite a bit to give it more flavor because it tends to be so bland. 6-8" seems to help.
I’m grafting my huge Shiro over to other varieties because it actually isn’t really worth the effort or expense (I often have help thin) for its mediocre fruit, based on my subjection.
Thanks, Alan. Will thin today. It has been a busy holiday weekend.
In defense of Shiro, it is a good plum for starters. It is very precocious, fruits early and a lot. For newbies to plums, it is an encouraging sign. It is a good tasting plum comparing to store-bought plums.
I am sure when my Satsuma or my E. Plums bear fruit, I will really understand your comment about Shiro.
I got my overset plums thinned on saturday morning. It got down to 28°F. Unfortunately it was about 98% kill. It was probably about 2 degrees too low.
Mamaug, it is also a sturdy J. plum, which is useful from Z6 on down. Some of my favorite plums, like Satsuma and Santa Rosa tend to get cambium damage on my site, about Z6, although not usually fatal.
When I first tasted Shiro I thought it completely wonderful, it was my first plum here. It can still be quite good if you thin enough. Those first plums had lots of leaf to plum.
Does anyone have any thoughts on thinning an Early Golden plum?
https://www.acnursery.com/fruit-trees/plum-trees/232/early-golden
I have one that has set just an incredible number of plums this year. With my beach plums I just let them all stay because they are little more than berries anyway. Early Golden is a small plum but still much bigger than a beach plum.
How many can I leave?
Plum wine and peach pickles
How many branches do you have? Maybe you can experiment with untinned, lightly and heavily thinned branches.
Oh wow. You are making me jealous. Most of my flowers are falling off.
@Ozymandias,
My Plums esp. Shiro and Castleton set like crazy. I’ve thinned them for better sized fruit and branch breaking prevention.
@PharmerDrewee,
Not having fruit set usually means no good pollination.
Did it rain a lot during bloom time?
Do your trees have good pollination compatibility?
Did you have hard freeze at bloom time or post bloom?
I think I had some misfortunes you mentioned during bloom. Some leaf sprouts look fried so there was likely a freeze unless it’s a disease. There were plenty of pollinators buzzing around the flowers but we did have a lot of rain. I had Satsuma bloom followed by Ruby Queen a couple weeks later but there was definite overlap.
Do you know if Satsuma and Ruby Queen are pollination partners?
Two weeks is a very long spread for my plums at least. 8 of my pulots where in bloom before Satsuma woke up at about a tie with Shiro, Santa Rosa and Burbank followed. But the pulots finished a lot sooner and my Shiro Burbank and Satsuma have oddly strong petal adhesion making them look like still in bloom but there clearly expanding fruitlets.
@mamuang they are both J plums so I assumed they’d be ok. Are some J plums incompatible? My other J plum, Sorriso di Primavera, only formed 5 flowers so not very useful. I’m glad I got scions from you of other varieties to graft.
@lordkiwi Satsuma’s bloom was very staggered. I think the cooler weather slowed everything down so the flowers did not open all at once. There were still unopened flower buds on Satsuma when Ruby Queen was in full bloom.
