Dry & Hot Areas
Over the years we have gained many friends who garden in countries with warmer climates like southern France or even hotter such as South Africa or southern Japan. We are grateful to them for giving us feedback on what does well and what does not in these hotter climatic conditions.
Generally we would suggest the following as a guide to those types that are happier in a warmer climate. However, all individual environments do differ, so we cannot guarantee success in any particular location.
Keeping the clematis moist at the root is key. Ensure that the compost does not dry out, nor become waterlogged from to frequent watering, then most clematis will cope with reasonably high summer temperatures.
Growing them in pots or containers of some sort is often a better way to ensure good soil and moist, yet free-draining conditions. We understand, for example, that the local soil in Madeira and parts of South Africa is not ideal. There is really no need to shade the roots - although it can help to retain moisture, it can also harbour slugs and other pests.
Most general advice is still the same as in England; feed them every two weeks even when they are flowering, and keep pale coloured types that are prone to fading, in shade.
As a guide, based on feedback from customers, you may like to try the following:
Most of the species, such as terniflora, orientalis var. orientalis and rehderiana.
Also consider the Cirrhosa and other evergreens, but they may exhibit summer dormancy, losing their leaves in the hottest months.
The Tangutica Group will be fine in drier soils but high humidity may be a problem.
Montanas generally, although they do need a good supply of water especially as they can become very large.
Most large flowered types, but prune back by half after the first flowering to avoid too much dead foliage building up. They will flower again 6 - 8 weeks later.
The Integrifolia Group and Texensis Groups, but these must be kept moist at the root to avoid mildew problems.