June is when we thin the fruit on the trees here in North Central Washington. You can pretty much tell which fruits will drop and which will stay ( I mentioned June drop in a previous post).
Even a week or two ago it was hard to tell which fruits would mature but now there no mistaking them. The pics below show a plum limb as was and then just after it was shook to knock off the ‘June drops’
This plum variety (Santa Rosa) is set very heavy, as is usual for these trees of ours, amazingly year after year. ( Most of our other plums don’t have much fruit on them this year, as a result of poor pollination) So there is still much thinning to do on it, to space out the fruit so they’ll size up to a desired proportions. Its too easy to under thin, I usually have rule of thumb or hand and try to go about 6 to 8 inches between fruits (do the Hawaiian hang loose sign, basically the space from thumb to pinkie). Its always difficult to tell when the fruits is so small, I try to imagine what it would look like with full size pome hanging there, to gauge my progress. Every year I tell myself “make sure & take enough off”, and I think I do but when I come back to pick I wonder if its even been thinned. So I’m resolved this year to thin everything twice to make sure theres less I miss. I usually do a fair job, but there are always clusters that are missed and fruit invariably under thinned.
When a tree has a heavy fruit set, probably 95% of the fruit gets thinned off, so its a bit disconcerting to see all the fruit on the ground. But if it wasn’t done you would end up with loads of real small (marbles) fruit.