Weeping Cherry Trees
June, 27th 2010
Weeping cherries are one of the most-requested trees in our nursery,
and one of the least understood. They also have a very high failure
rate; after dogwoods they are our highest warranty cost item. We like to
joke that each weeping cherry is actually two trees in one, so they
have twice as many problems.
What we mean is that each weeping
cherry tree has two parts. The roots and trunk (called “rootstock” by
nurserymen) are actually a fast-growing sweet wild cherry (usually
Mazzard or Mahaleb cherry) like the ones that grow along the roadside,
but trained to a single straight trunk. The weeping part or “top-graft”
is either double-flowering pink Higan cherry (prunus subhirtella) or
“Snow Fountains” white weeping cherry (prunus “Snofozam”). The two
plants are grafted together at the top of the trunk, about five feet
from the ground. The weeping section provides an umbrella effect if it
is pruned regularly, or can grow 25 or 30 feet tall if not cut back.
is common for sprouts or “suckers” to grow on the trunk or rootstock.
If these are allowed to grow they will shoot straight up and take over
the tree, ruining the weeping effect. There is a graft scar at the top
of the trunk, just below the weeping branches. Anything that sprouts
below the graft scar is wild cherry, not weeping cherry, and must be
removed. This can be done at any time of year, the sooner the better.
often ask us for “dwarf” weeping cherry trees. There is actually no
such thing. Any weeping cherry tree will eventually grow to thirty feet
tall and twenty feet wide if not constantly pruned back. The small
weeping cherry trees you see in landscapes are probably still young;
once they grow too large for the space most people remove them and start
over. Clipping the tree each season can limit its size.
weeping cherry trees are typically top-heavy and need staking for the
first year or two to keep them straight. We’ve seen many people try to
prop them up by heaping dirt around the base or planting them deeper,
but this will kill the tree sooner or later (most likely sooner).
Planting any tree deeper than it was growing in the pot or root ball
smothers it and kills it.
Over-watering is another frequent mistake
with weeping cherry trees. Cherry rootstocks are actually very rugged
and will tolerate dryness, but are very sensitive to excessive wetness
and will drown if over-watered. A deep-root soaking (five gallons or so)
once a week is usually enough to maintain newly planted weeping cherry
trees. Once the trees are established they should not need watering at
Japanese beetles and tent caterpillars love cherry trees,
weeping cherries included. Spraying in May and June with BT or fruit
tree spray can prevent this problem. Another fix is applying Milky Spore
under cherry trees, which will control Japanese beetle grubs quite well
over a long period.
People often ask whether the weeping
branches should be trimmed off before they touch the ground. Our answer
is no, unless you like the “bowl around the head haircut” appearance.
Once the branches touch the ground they stop growing, so you get the
effect of a gorgeous fountain by not trimming them off. Anywhere you
trim, weeping cherries will fork. To get the best effect you should trim
within a foot or two of the top graft. This will create more shoots and
lead to a thicker appearance. The best time to trim weeping cherry
trees is just after they bloom in early spring.