Hello, I live in Kansas, zone 6b - though in summer, we might as well be zone 9 or 10 - and this is the third year I have tried growing dwarf prunus incisa, the specific cultivar is Kojo no mai, or contorted cherry (there is a new trademarked contorted cherry out there in the past 2-3 years called Little Twist; this is essentially the same plant). I have two 1g sized trees, currently in pots (the location I want to plant them isn't ready yet); they are in the courtyard where they receive either very bright shade or sun most of the day, and I am keeping them moist the way I do my potted Japanese maples, and they are in a well-draining, yet moisture retentive mix of high quality potting soil with perlite, pine bark mulch, coco coir, and turface (again, same as my maples). Each year, it's the same thing: they bloom, leaf out nicely, then start to get burnt edges on the leaves, and drop the leaves. Then, the second set of leaves comes out just as nice as the first, the pattern repeats, and eventually the tree dies, either by fall or over winter. The past two summers have been exceptionally hot, with high 90s or triple digits for most of July and August, and I have noticed that these shrubs seem to be a magnet for mites. Once I've noticed the infestation, I treat them weekly with either the Bayer 3-in-1 Insect, Mite and Disease control or Captain Jack's Dead Bug Brew. With my current two, I am now on my third treatment with the Captain Jack's. Has anyone else found that their ornamental cherries are magnets for mites? How many sets of leaves do the cherries have (I know maples have two)? Any suggestions or recommendations for what I'm doing wrong, or what I could try, would be greatly appreciated. I really like this little cultivar, but if I lose these two, I'm done with them. :(
That could certainly be a possibility, that we're just too hot for this cultivar. Have you heard of mites being a significant problem with the ornamental cherries? As mentioned, this year and last year for sure, and quite possibly the summer before that, it's like I can't keep the mites away from them. Most of my other trees are fine (one of my maples is having some issues, but the others aren't thus far), but the cherries are just loaded.
Mites can be murder on plants coming from more cool and humid areas, when these plants have been placed in a hotter and drier environment.
These particular two came from a nursery in South Carolina in March; I would consider SC likely similar to us in humidity, and quite possibly heat too. (Kansas is actually quite humid in summer)
Yes, it's surprising Toto's fur remained so curly. Wet conditions are so unfavorable to plant-sucking mites that occur during summer that one of the common recommendations for suppressing them is to hose plants down with jets of water.