"Treetops" wrote:

I need to move my PJM Rhodos; too much sun and crowded. They are just
starting to blossom (zone 4) and seem fairly healthy.
What is your opinion on moving them as soon as flowering is completed
and before the full heat of summer?

When transplanting a large plant several steps should be followed.
First, it is best to stimulate a tight root ball by root pruning the
plants to be moved about a year before moving. This is accomplished by
cutting a circle around the plant stem with a shovel to cut off roots
that extend beyond this point. This radius is usually slightly smaller
than half way to the drip line. Second, it is best to move when the
plant is dormant and not stressed. This would be in the spring and
fall when the plant is still dormant but the soil is not frozen.
Moving in the fall before the ground freezes is preferable if you
don't have a problem with frost heaving. Sometimes winter freezing and
thawing cycles can actually lift a transplanted plant out of the
ground where the roots are then desiccated and the plant dies. For
this reason, it is safer to transplant in the spring after the ground
thaws in climates where frost heaving is a problem. Third, take
precautions to preserve the integrity of the root ball. Tie the ball
together and support is so it doesn't fall apart. Finally, pruning the
top helps match the demands of the top to the capability of the roots
after they are stressed by the move. People have been known to cut the
top off wild rhododendron before moving and the plants have come back
with superior shape. This is drastic and not recommended for a plant
you don't want to risk loosing. Rhododendron and azaleas have dormant
buds beneath the bark which sprout to form new growth after severe
pruning, hence severe pruning which removes 1/3 to 1/2 of leaf area is
quite common when transplanting.

In general you can transplant your PJM's anytime, but by not following
the above procedure, you are increasing the set back they will take.
If they are stressed already, they may not recover.

In any case they will need watering for a while until they get
established. Don't overwater, but make sure they get water when they
start showing any wilt.

Visit my Rhododendron and Azalea web pages at:
http://www.users.fast.net/~shenning/rhody.html
Also visit the Rhododendron and Azalea Bookstore at:
http://members.aol.com/rhodyman/rhodybooks.html

Cheers, Steve Henning in Reading, PA USA