Trees tolerant of hot, dry conditions
Trees planned for free-draining, south-facing slopes in southern areas are likely to suffer from hot dry summers and prolonged drought in future. The following are suitable;
Crataegus crus-galli: Small spreading deciduous tree to with long thorns.
C. × persimilis ‘Prunifolia’ AGM: A better garden tree and almost as resilient.
Juniperus scopulorum: A small conical coniferous tree, with reddish bark,
and bright blue-green foliage. Almost as robust and better for garden use is J. scopularum ‘Skyrocket’ whose spectacular narrow form is a welcome addition to many gardens.
Gleditsia triacanthos: The yellow leafed cultivar ‘Sunburst’ is best for garden use and has the RHS AGM, with bright yellow young leaves ageing to light green by late summer, and is significantly smaller than the green leafed species.
Catalpa speciosa: Not widely grown but has considerable potential for dry conditions, but has similar foliage and flowers (although more sparse) as the common but not particularly drought tolerant C. bignonioides.
Eucalyptus pauciflora subsp. niphophila AGM: A particularly hardy evergreen tree noted for its attractive flaking colourful ‘snakeskin’ bark. However, eucalyptus have been frequently implicated in subsidence and gardeners should be wary of planting near buildings.
Ginkgo biloba AGM: A robust deciduous tree with striking foliage. Female plants produce fruits which can be a nuisance in autumn. Male plants are trouble free.
Koelreuteria paniculata AGM: is grown for its yellow summer flowers followed by bladder like fruits.
Pyrus calleryana: A very robust deciduous tree widely used in landscaping. The cultivar ‘Chanticleer’ has the RHS Award of Garden Merit with a neat conical habit making it suitable for large gardens.
Cedrus atlantica: A large conifer, conical when young and spreading when taller. The blue leaved form ‘Glauca’ has the RHS Award of Garden Merit and is especially spectacular as a specimen tree for very large gardens and public open space.
Quercus ilex AGM: A large spreading evergreen with attractive green foliage that is suitable for the largest gardens and parks.
Trees tolerant of waterlogging:
Prunus padus: A small decicuous tree with striking flowers and young foliage and shoots. The cultivar ‘Colorata’ has the RHS Award of Garden Merit and especially attractive pink flowers followed by dark fruits.
Salix alba: A compact medium sized tree that is very tolerant of wet soils. Two cultivars that have the Award of Garden Merit are S. alba var. vitellina 'Britzensis' (m) AGM with coal coloured young stems and S. alba var. vitellina AGM with bright yellow shoots.
Acer rubrum: A large spreading deciduous tree with remarkable autumn colour. The cultivar is an especially valuable tree for very large gardens and parks:
Taxodium distichum AGM: A large deciduous conifer that is fairly tolerant of drought as well as very tolerant of waterlogging. This tree has an Award of garden Merit but is really suited to very large gardens or public open space.
RHS Plant Selector