If you haven't been spraying those cherries at least every two weeks with pesticide, each one will have a little white worm inside by the pit. At least that's what happens here in Utah and many other places. I just harvested my first really good crop from my Lapins cherry trees, and they're wonderful! But because I only sprayed once about a month ago (it's been a very busy spring with a new baby in the family and a big vacation a few weeks ago!) about 10% of my cherries have worms. So, we're cutting most of them open before we eat them and discarding the wormy ones. But since nothing beats that great feeling of popping a whole cherry in your mouth and letting the juice squirt all over your tongue, I can't resist just eating some of them without checking! A little worm won't kill me, I suppose! But anyway, I'm not sure you really want a tree that's half Kwanzan and half wild cherry! I'd probably cut off the wild branches and buy a new cherry tree to plant somewhere else nearby. I do have a related question, though: I have four Kwanzans and one is nearly dead. From what I've observed in my garden, the ones getting less water are healthier. They're in an area with a gravel mulch and they only get water from a drip system. The one dying is in an area that is sprinkled with a groundcover around it. Is that your observation -- that these trees are sensitive to watering and like to be a little dry? Also, my dying one has suddenly shot out a bunch of suckers at the base -- so, should I be pretty certain it's on wild cherry rootstock? Would that look attractive as a shrubby, multi-trunked tree if I let these suckers grow and cut out the mostly dead Kwanzan from the middle of the clump?

>Prunus x yedoensis (Yoshino) cherries have an ability to get much larger than the 'Kanzan'......almost double the size< Both are large and vigorous Japanese cherries, which tend to produce generally similar individual crown dimensions. For example a 'Kwanzan' in Sultan, WA was 50 ft. high in 1993; another example, in Sumner, WA had an average crown spread of 55 ft. the previous year. P. x yedoensis has been measured 55 ft. high in MD (1990), and with an average crown spread of 65 ft. in Seattle (1993). More recent (~2005) measurements for Seattle (USDA 8) include a 'Kwanzan' 53 ft. high, another with an average crown spread of 57 1/2 ft., and a Yoshino cherry 57 ft. high. The charm of the Yoshino is in its perfect balance: its dark rugged trunk, often burly and besprouted, makes an ideal contrast for the quintessentially delicate pink blossoms. Nor is the tree so fussy and weak as the winter-blooming Higan cherry, or so bloated and gaudy as are 'Kwanzan' and the other Sato-zakura --Arthur Lee Jacobson, Trees of Seattle - Second Edition (2006)

i had a kwanzan flowering cherry i planted it march of last year. it did great last year, but in april of this year we got 10" of rain and our yard has lots of standing water in it. after that the leaves turned brown and fell off and it died. i think is was root rot. have you had excessive amounts of rain lately?

Lots of similar issues here near central MA too in condo complex. My neighbor's Kwanzan cherry did not bloom and it used to reliably every year. Her Rose of Sharon has not a speck of green on it. Another neighbors ROS is a bit better. Nobody's forsythia bloomed. Endless Summer (bummers) super slow coming up from base. Nothing from stems. Many Jap Maples (probably Bloodgood) are skimpy. another Viburnum has a large section dead. My knockout rose only has a few bits coming up here and there. This pic was yesterday. Last year it was full bloom on 6/11. Trying to decide if I should wait or trash it. Came here to start my thread for the rose, but I'll join here... so we can all commiserate! Oh, another one... a friend in southern NH's clematis Jackmani looks quite dead with just small bits coming up at the base. She said her obelisk toppled over the winter so maybe some stress played into it. My clematis's are fine thank goodness!