Summer Flowering Shrubs
Gordon Link, from The Gobbett Nursery, with a selection of desirable summer flowering shrubs for late season colour. - 10 August 2018
While most people use herbaceous perennials as the mainstay of their summer borders there are quite a few interesting summer / early autumn shrubs for added interest. These are a few of of my personal favourites.
On the nursery we grow quite a few different Deutzia. Two of my absolute favourites are Deutzia hookeriana – flowering June and into July, and smothered with dainty pale pink cup shaped flowers. It has a very compact habit, only growing to about one metre.
The other Deutzia I wouldn't be without is Deutzia setchuenensis 'Corymbiflora', which in June & July is smothered in small, pure white star-shaped flowers. This Deutzia has probably the longest flowering period of any of the species. It will grow to about two metres but has taken about fifteen years to reach that height here in Shropshire.
Now while not classed as a shrub but a woody perennial, Amicia zygomeris is a late flowering woody plant with large yellow pea like flowers and heart shaped leaves with purple / red stipules, said to be hardy to -10c but really needs a mulching for the winter as it comes from Mexico.
Another tender shrub well worth the extra trouble of a bit of winter protection are the Anisodontea (Cape mallows). If you have a very sheltered spot in the garden, sunny & well drained or in pots, they will be covered in pink flowers all summer & autumn. Take pots into the conservatory or greenhouse for the winter & they will continue to flower almost all the year around.
Anisodontea hydomandarum will grow to about one metre covered with small bright pink flowers.
Anisodontea capensis - small hibiscus-like pink flowers, or choose the variety 'El Rayo' with larger bright pink flowers with a purple heart. Hardy to about -5c.
Now we have all seen Buddleia davidii with its large pointed flowers, hopefully covered in butterflies in late July into August. Not quite as well known are Buddleia x weyeriana hybrids, originating from crosses of Buddleia davidii with Buddleia globosa. Buddleia x weyeriana 'Sungold' grows to 2 – 3 metres high with clusters of clear yellow flowers, usually starting to flower 2 – 3 weeks after Buddleia davidii but still as attractive to bees, butterflies and other insects. They have a much longer flowering period than Buddleia davidii, usually flowering until the first frost. Like most Buddleia give them a good hard prune in March / early April.
There are other varieties available but not all are easily obtainable, such as 'Pink Pagoda' and 'Bicolour' (syn. Flower Power), which has purple buds opening to shades of pink & orange.
Now a completely different beast is x Chitalpa tashkentensis 'Summer Bells' which is an interspecies hybrid between Catalpa bignonoides (Indian bean tree) and Chilodsis linearis (Desert willow). With six inch long lance shaped leaves, this large shrub or small tree produces masses of orchid-like, frilly pink blooms with a yellow throat in late spring and throughout the summer. It is fully hardy in the UK and flowers from a very young age and is drought tolerant. It grows to 3-4m in any well drained soil.
Clerodendrum are really useful late flowering shrubs or small trees. Of the four hundred or so species only a couple are really hardy in the UK conditions. Clerodendrum bungei has large heads of rosy–red flowers from August until October, it may get cut back in severe winters but will shoot readily the following spring. Growing up to 2m it is happy in full sun or partial shade and is an excellent late nectar source for insects. It can sucker profusely after a few years.
Clerodendrum trichotomum fargesii (Glory bower tree ) is a fantastic late-flowering large shrub or small tree, flowers from early August, has white flowers with purple/red calyces followed by unreal looking metallic blue berries enclosed by maroon calyces. Clerodendrum trichotomum fargesii will grow to about 5m but can be kept pruned to about half that height, and is happy in any reasonable soil in sun or shade.
Gordon and Christine Link own The Gobbet Nursery, based near Kidderminster in Worcestershire. They specialise in shrubs, especially Cornus and Syringa, and in Dierama and Pacific Coast Irises.