This happens with cherries when the more vigorous graft stock (the upright branch with white flowers) grows away at the expense of the grafted scion (the pink flowered weeper). You could cut off the upright branch but it has been growing for a while so your tree will be left looking lopsided.

get rid of the whole tree ... and plant a better one ...

the pink flowering parts... are not as vigorous as the other ...

so in propagating it for fast sale ..... it is grafted onto the more vigorous lesser flowered stock.. for roots and trunk ...

due to some injury ... a side shoot of the understock.. was allowed to take over the top ...

you either remove it ... or it will..eventually take over...

but i think i see some serious prior damage on this thing ...

and for the 3 to 5 years it would take to repair it ... and considering the size of your garden ... i would just go buy a new tree.. and plant it a foot or two over.. where you can dig a hole..

simply cut it at ground level.. and use a stump killer to kill what is left in the ground .. or dig it out ...

which all summed up.. is what flora said.. lol

good luck

ken

get rid of the whole tree ... and plant a better one ...

Harsh, man.

You do have two different trees growing out of the same trunk. That's what can go wrong with a process called grafting. Grafting is the process, commonly used in horticulture, where a vigorous root system is attached to a desired branch, allowing the vigorous roots to feed a prettier tree than it would have naturally. Kinda like taking someone else's head and attaching it to your body ;)

What happened in your case is that the rootstock decided to grow its own natural branch, which is taking over the whole tree. Its as if the body tried to grow a new head. ;)

get rid of the whole tree ... and plant a better one ...

Harsh, man.

It's not harsh at all. When the rootstock attempts to take over on a grafted tree like a weeping cherry, there is little point in trying to maintain the tree. Removing the suckering rootstock will essentially remove half the tree - leaving it in place, it will eventually overwhelm the grafted portion. Either way, the tree looks ridiculous and will continue to suffer problems.

Grafted weeping flowering cherries are pretty much a waste of effort any way you look at.........short-lived, offering a two week bloom period at best, highly disease prone, high incidence of graft failures and one of the most often mispruned ornamental trees in existence. One can make so many better choices if you want a small flowering ornamental.