Hi Steve,
It's beginning to sound more like drought, as bnd 777 suggests.
Since they are both in shade, there will be competition from the roots of
the neighbouring shade-casting planting, as well as the rain-shadow from all
that foliage.
The damaged leaves will be shed soon anyway, so I would be inclined to water
and mulch generously now. Before you do, inspect the ground around the
roots. If it is compacted, aerate the ground with a fork(as you would for a
lawn) so that the water can more easily reach the roots. It will also help
the roots 'breathe' and expand. In the spring, try a balanced fertiliser
followed by a high potash feed (rose or tomato food) during or after
flowering.
Spider

Steve Harris wrote in message
...
In article ,
(Spider) wrote:

However, the scorched leaf margins suggest it would prefer a bit
more shade.

Neither of the clumps is really in full sun and one os seriously dark.

Steve Harris - Cheltenham - Real address steve AT netservs DOT com