We have a plum tree that is covered in blossoms in the spring; each year, as summer starts, there are lots of plums developing. Then later in the summer. almost all of the plums drop off, or in some cases are blown off by relatively moderate winds. Can anyone tell us why this happens, and what we could do to prevent it?
Hi Pauline: Can you tell me what variety of Plum you have? How do you water your tree and how often do you water? Do you fertilize your tree, if so, what kind of fertilizer do you use and what time of the year do you fertilize and how much fertilizer is applied to your tree? If you can, tell me about your growing conditions. Depending on what kind of Plum you have fruit drop is a normal occurrence. It is the trees way of thinning itself when we have not tried to thin the fruit ourselves. Juvenile as well as mature fruit can fall off the tree very easily if we have too many Plums on the tree to start with. Thinning the tree is the best preventative but you also may have a nutrient deficiency that can cause a lot of fruit to fall off the tree. Also, lack of water can be a major concern which can lead to excessive and premature fruit drop. Jim
I'm not sure of the exact variety, but the plums are relatively small, green when unripe, and yellow when ripe; they are very sweet and tasty. The tree is about 20 years old, but the problem only began about 4 years ago. The plums fall off the tree when they are still green and hard, so that we only get a few (maybe 10-12) that make it to ripeness. We haven't been in the habit of watering, since we live in a fairly rainy area on the coast of Nova Scotia (even when it's not actually raining, it's often foggy). Our neighbours have a similar tree, and they seem to get lots of plums. I asked them if they water, and they told me they don't. Thanks for replying to my query; any advice you can give will be most welcome.
Falling Prune Plums Mr. Shep, I also have a similar problem with my prune plum tree. Our situation in in Coastal Maine sounds very similar to that of Miss Allsop - fairly frequent rain fall, a lot of fog. I have fertilized the tree with 5/10/5. I would appreciate any help you can provide.
I think both of you will need to thin the fruit on your trees in the future. We start to thin the fruit here in late March as our Methley and Santa Rosa Plums are ready for picking by early to mid June. We will thin out the misshapen, the undersized and any scarred fruit in order for the fruit we want to harvest to get some size to them. I think with your weather conditions both of you will have to start thinking in terms of using a copper or calcium based dormant spray as the blossoms are starting to swell in the Spring but you will need about 48 hours of no moisture, fog, drizzle or rain for the sprays to be effective. Pauline: I suggest you try to get a copy of this if you can. http://www.cbsc.org/ns/english/display_lib.cfm?Code=163186&coll=NS_Lib_Coll_E Sometime tell me if you see anything like this on your trees. This disease can severely affect your production of Plums where both of you are. http://www.nysaes.cornell.edu/pp/extension/tfabp/blknstf.shtml http://pmo.umext.maine.edu/factsht/blknot.htm If a disease is not causing your fruit to drop prematurely and the tree is not shedding itself of fruit that it feels it needs to let go of then I suggest you thin some of your fruit right now if you can to protect the majority of the Plums. It could very well be that neither of you are getting enough sunlight to sustain your Plums normal growth. When that happens the fruit will be sloughed off rather easily, even a mild wind can make the fruit fall off the tree. For me to pinpoint what is causing the excessive fruit drop, both of you, or one of you will have to give me more information to go on. Let me ask both of you this, is there any selectivity of the fruit that is falling off as opposed to what is being left on the tree? Are the misshapen fruit or the fruit that is coloring up first being sloughed off first and the larger, normal fruit being left alone for the most part and are being left on the tree? Jim
Jim, thanks for the information. The plums that have fallen are just starting to turn from green to purple-they seem to be in perfect shape except that they are far from ripe. When you suggest "thinning the fruit" does that imply pulling off the individual plums where appropriate? Lastly, I see no signs of Black Spot.
Hi Ewenx: The Black Knot would probably be your worst fear for a disease. It can cause an entire crop to fall off the tree prematurely where you are. Not so much in commercial operations but in home gardens, we do see Plums that are just starting to turn color fall of the tree long before they are ripe. It is quite common with the American and Japanese Plums. Can you give me an estimate as to the number of Plums that have fallen as opposed to the number left on the tree? Are we talking about a bumper crop in which a few dropped Plums will not make much of a difference to the entire crop as a whole or is it that normal and good sized Plums are being sloughed off and Plums not as good are being left on the tree? The reason I asked is that in cooler climates such as yours the earliest fruit to set can be the first fruit to be sloughed off by the tree. Even more so true when you are not getting ample amounts of sunlight. In home gardens it is essential to thin the number of fruit that have set. Once the fruit generate some size and there are too many Plums on a branch we risk breakage of the branch, unless the limb is staked or propped up, which causes us much greater problems for the immediate future. Tell me as much as you can about your tree. Post some pictures of it if you can and I'll see what I can do to help. Jim
