I have a twelve year old Pissardii Plum at the front of our property. At this time of year it is beautiful - the blossoms are among the earliest in the neighbourhood. However, I actually planted it for the dark purple foliage and over the last few years I have had increasing problems with disease. Some kind of shothole fungus and perhaps something else that is causing the tree to look very ratty very quickly. I notice that other plums in the area are similarly affected. The local garden centre suggested I just feed it well. So, I put those fertilizer spikes in the ground a couple of times a year. I also use lime sulpher dormant spray a couple of times in the winter. This tree has also been plagued with water spouts but I can live with that if I can get the foliage to look halfway decent. I have a similar sized Robinia "Fresia" on the other side of the driveway and, as you can see in the picture, the contrast in leaf colours is striking. However, if I cannot find a solution for the plum I think I will be forced to replace it with something less disease prone - but I really don't want to.
Hello Westcoastgarden It would be a shame to see you rip out a nice tree without trying to save the plant first. Firstly take a leaf or two or three to a good gardencentre where there are knowledgeable staff such as Mandeville or Gardenworks. get them to look at the "shothole fungus" and give their expert advice. or you could take leaves out to BC Ag in abbotsford and get them (for a fee of course) to diagnose the problem. Usually the registered control measure is to spray with a systemic fungicide in addition to the lime sulphur dormant oils in winter. the gardencentre should be able to point you in the correct direction. before you fertilize get a soil test done. this will tell if there are any nutrient deficiencies in the area. the robinia may be sucking all the nutirents away from the plum (Just a hunch). I have always found that granules work better than those stick things. theory is that granules will disolve over time just like sugar does in a coffee. but you have to stir a sugar cube to get full dilution (just my opinion) if you could post a picture or two of the disease and damage you are talking about that may help with your curative. don't give up on the tree yet. It may be something that we have to live with in the "wet coast" Pierrot
Thanks for the advice Pierrot. I have been trying to deal with this for several years. I am really torn. I try to avoid chemicals as much as possible in the garden. If I have a plant - even a tree - that is going to need constant applications of chemicals then I would prefer to replace it. The robinia is thirty feet away and across a driveway. I don;t have any pictures of the leaves and they really don't start showing problems until around July. I am hoping to try something before then. The plum still looks ok despite the rattiness - my concern is that other trees in the neighbourhood look significantly worse and I would like to avoid getting to that point. On the other hand, if there is no avoiding it without the constant use of chemicals then I would like to know now. It is such a pervasive problem around here (Maple Ridge) that I was hoping someone on the forum might have experience with it. Thanks.
I understand the concerns with the chemicals. there is too many people that are spray heads and just wanna spray spray spray!! try increasing the fertility of the soil around. healthy body healthy mind kind of argument. the increased nutrients may or may not help if there is a large source of innoculum around the area. fixed copper is an option but you have to coat the whole tree. impractical if it is a large tree. that'st why I suggested the systemic. it is a minimal amount of chemical and works like penicillin through the body of the tree and is limited to that tree. it is the least chemical of all treatments. not trying to convince you to use chemicals jujst trying to give options to save the tree!! good luck Pierrot
Nothing new there, they always do look ratty by summer. Don't bother with those fertiliser spikes, they are made by the same people that make snake oil. You get a tenth of the nutrients for ten times the price, and applied in a way that doesn't help the tree much. If a soil test shows that the fertility is low, then use a granular broadcast fertiliser (or better, a good organic mulch). But only if a test shows it is needed.
I haven't tried copper before and I have a ladder. When do I apply it? Too bad about the spikes - they seem like a good idea. However, I add a lot of organic material (mostly compost and mulch - sometimes well rotted manure) to my garden every year and judging by the rest of the plants, I don't have a nutrient problem. My Montmorency Sour Cherry in the backyard has similar issues to the pissardii plum but I am less concerned about the appearance of that tree (and it produces well) - however, if I am going to get fixed copper maybe I should spray it as well?
I agree with the group that hates the spikes. they provide localised fertilizer and are not conducive to an expansive, effective root system.
It is hard for me to equate this disease as being shot hole as we first see it in the early Spring even while the leaf has just emerged and is starting to expand. I never see shot hole fungus on our atropurpurea Plums here when I can see the symptoms rather easily on nearby Apricots, Almonds and some but not all fruiting Cherries in the very early Spring after a missed fungicide spray or due to a mistimed spray application. I see the symptoms on these trees and later on the fruit much more readily than I will on Peaches, Plums and Nectarines here. The leaf spot and fruit speckling form of shot hole fungus otherwise known as Coryneum blight here that attacks our fruit trees, may not be the same pathogen that is affecting this Plum and the Cherry as surely if they were the same the symptoms of the disease would be seen long before July on both plants. If the use of copper based fungicide sprays is an issue then you have two choices, either live with it or do a better job of cultural control. Do not allow the fallen leaves from affected trees to overwinter on the ground as the pathogen will be harbored in those leaves and can also be harbored in the compost and the mulch near the base of the tree. Rake up and collect the leaves almost as soon as they hit the ground in the Fall is the best preventative for the ornamental form of the so-called shot hole fungus. Jim
Yes: Probably not actually Prunus shothole, I changed the wording I used (because it was what you called it). The Prunus cerasifera you have may not be 'Pissardii' ('Atropurpurea') either, it looks rather dark in your photo. (Also: The Robinia pseudoacacia cultivar is spelled 'Frisia').
