Rose of Sharon (Hibiscus syriacus) can be pruned back hard in late winter or
early spring.
Young plants typically have a habit much like you describe but will become
more shrub-like with maturity. This
plant is very late to leaf out so don't panic when it looks like a dead
stick well into spring.
Dipladenia (aka Mandevilla splendens) is a lax, vining shrub. It too can be
cut back hard as new growth begins in spring.
It will need a cool, bright environment for the winter - a greenhouse is
ideal but a sunroom or unused bedroom will work
as well. Keep on the dry side, watering only to prevent it from fully drying
out. It will need to be re-acclimated before
you move it back into the garden for spring. Watch out for spider mites,
which can be a problem with overwintering.
pam - gardengal
"Ted" wrote in message
ups.com...
OK, I have these two shrubs (I am not sure of the spelling of dipladema
as I don't have its card in front of me, but I was told butterflies and
hummingbirds love them). I notice that on both, the blooms are located
on new growth.
I find the structure of both wanting as both have stems that are a
little less than a metre without branching. It looks like a case of
strong apical dominance.
I have to keep the dipladema reasonably small because I will have to
bring it in each fall (the horticulturalist I spoke to when I bought it
told me to bring it in before it gets hit by frost since it is not
winter hardy here, just north of Toronto - she didn't say what to do to
over-winter it inside or what to expect it to do).
Both are giving a terrific display right now.
Do you have any experience pruning these shrubs? If so, when is the
best time of year to prune them? And when you prune, should the focus
be on thining the plant, or reducing the height? In both cases, how
much should be removed? Can I thicken up the plants by snipping the
shoots just below the growing tip of each stem I want to branch? If
so, how much should be enough to end apical dominance in these plants
and encourage the stems to branch? Am I right in expecting that doing
so will improve their displays next year?
Thanks for your time.
Ted
R.E. (Ted) Byers, Ph.D., Ed.D.
R & D Decision Support Solutions
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