On Oct 11, 7:51*pm, Phisherman wrote:
I have a tropical hydrangea (survived by yearly winter leaf
mummifications) that has grown too large and up against my house. Can
these be divided in the fall? * * Zone 7, east TN.

Hello, Phisherman. "Tropical" hydrangea? Are you referring to Dombeya
Hybrids from Africa? Or the evergreen Climbing Hydrangea called
Hydrangea seemannii, which is native of Mexico? Or... something
else....? If you mean regular ole' hydrangeas then:

I have not tried dividing hydrangeas (or any other woody plants for
that matter) but many people report success doing that. Hydrangeas
that develop multiple canes have a better chance of success that those
growing out of a single trunk (climbing hydrangeas and some
paniculatas sold as trees). Think of dividing as if you were
transplanting the shrub, except you are transplanting only a portion
of it. It works with either plants that were just recently purchased,
with old potted hydrangeas or in-the-ground hydrangeas. However, it is
easier to divide a potted hydrangea because the soil has not
compacted.

Timing - I would do this either in winter (when the plant is dormant)
or in early Spring. Try to salvage as much of the root system as you
can since this will ensure a good supply of moisture; that includes
the smaller fibruous roots. You may need an axe, loopers or snips.

Mulch well afterwards and be prepared to water the rootball area only,
until the plant develops new roots in its new location. There may be
water issues during its first year so be on the lookout for soil
moisture problems, especially during its first summer.

If you are just trying to propagate, I suggest instead propagation by
cuttings or by air layering as these methods are easier and less risky
to the mother plant.