On 03/04/2017 13:05, earthstick wrote:
3 years ago I bought a fruiting cherry tree along with an apple. The
apple tree is coming along fantastically but the cherry refuses to
grow any branches.

Do you know what variety of cherry you have bought? And what rooting
stock it is on? That will help determine the right advice.

When it arrived it was shaped like Y and it has remained shaped like
a Y. It gets buds, leave and even a few cherries. The two branches
grow longer but the are no side branches growing.

Last year I tried trimming off every other bud to try and promote
side branches but that didn't work. This year I cut the two branches
down by about a third with the hope that the ends would grow new
branches but it looks like it's just going to bud again. What if I
had let the two branches grow long enough to bend down? Would it
have branched at the bend?

If you aren't sure what to do then "If in doubt do nowt" is a very good
maxim. No point in pruning it until it is a bit too big for the space
(although taking off the ends of lead branches should be one way to make
it branch from the next two buds down the stem).

Bending the branches down a bit towards the horizontal is supposed to
help encourage fruiting rather than vegetative growth.

I prune in early March because I have read they are susceptable to
frost damage if pruned earlier.

It is on a vigorous rootstock in a sheltered but sunny space and I
choose a variety that has no special soil type requirements.

Are you sure about that? A sweet cherry on a vigourous rootstock will
continue growing until it is huge. Semivigorous limits them to 20m.

If the scion isn't doing well and then typically the rootstock responds
by throwing up lots of suckers and robbing the scion of vigour.

One thing I remember is that when I planted it I could not tell where
the soil line had been and guessed. I planted it with the rootball
was a few inches below the soil line. I can see the graft is
probably 4 inches above the soil line now. Could this be the cause?

If you got it wrong by more than a couple of inches it might slow down
the rootstock for a while but if it survives the shock of being buried
too deep then it will adjust its root depth within a year or too.

Is the tree properly staked against wind rock? That would be another
thing that might prevent it from growing away properly.

Are you sure it isn't a slow growing vertical habit cherry variety
intended for a small garden by being slender and vertical?

The classic ornamental cherry of this character being "Amanogowa" (lit
Milky Way) but in American English "Flagpole cherry". But even that
branches - it is just that the branches all quickly become vertical.

RHS has a page on cherries which might help:

https://www.rhs.org.uk/advice/grow-y...fruit/cherries

--
Regards,
Martin Brown