It's probably the heat. Cherries don't do well in the heat. It should start to get better by the end of September if you keep the tree consistently watered. If you really wanted to go out of your way to tend to the tree, you could mist the leaves during the middle of the day (sometime between 12:00 to 4:00 ). I've even heard some people have very lightly sprayed their trees with mineral oil, or lightly rubbed some petroleum jelly onto the leaves, to help keep them from drying out. It's the height of summer right now, and a little browning is to be expected. San Jose has clearer skies than San Francisco, so less protection from the sun. In short, what you are seeing is perfectly normal for the climate you are in. There's a reason most commercial cherry orchards are based in Michigan and Eastern Washington. Also, in San Jose (all the paved surfaces in the surrounding area has an effect on temperature) it's quite likely your kwanzan trees are not getting quite the degree of winter chill that they would prefer. This results in slightly reduced vigor, and that is also associated with browning of the leaf tips. Your tree should fair better in future years when the roots have become more established (and they can provide a more adequate water supply to the leaves).

Have you grown any ornamental cherries before? Let me just say..........they have issues, some more than others :-) In my area, Prunus subhirtella 'Autumnalis' has more than most. The late season bloom period is very sparse, usually producing 10% or less of the more typical spring bloom, so the 'autumn' part of the tree's appeal is underwhelming at best. It is also prone to the same host of disease and insect issues other flowering cherries are. Most trees in my neighborhood appear more dead than alive as a result. YMMV As to how to prepare for planting and how to plant, your local Tennessee Arboretum has an excellent planting guide. I'd suggest you read it carefully and follow it explicitly for best results. Planting a Tree or Shrub

Looking for white or pink cherry blossom trees. Have you seen them around? I looked at HD & Lowe's.

baby scale move only at a certain moment in time ... and you have to kill them right then ... before they develop the hard cover that protects them .... you might contact your local county extension office.. to find out when they are active in your area .... once they get where they are going ... they attach themselves to the tree and start sucking vital juices ....... and can be killed by the proper oil treatment ... the down side is.. they dont disappear ... so you have to scrap a few off.. and see if they are already dead.. or still alive.. and then act accordingly ... what i trying and failing to get to.. is that it is possible.. they are all dead .. and we would suggest you not continue treating.. until you figure out if further treatment is necessary ... gently scrape a few off... and see whats underneath ... if it is just an ornamental flowering tree ... no fruit to eat.. you might be able to treat the soil with a systemic so that it will kill all the sucking scale ... and a lot of other bug problems .... if you move toward a more powerful resolution.. make sure you use a product labeled for scale .... not all insecticides will work ... thats a pretty nice young tree .. i dont see any reason to get rid of it... IF you are willing to do what is necessary to solve your problem ... ken ps: last year plague is not related to this plague ...