Continuing our weekly editorial on the various soil conditions to which shrubs are suited, this piece is devoted to the care, cultivation and establishment of shrubs in predominantly alkaline soil content. Soils of this nature are generally described as chalky, although they can vary considerably from stony and shallow, to clay-like. The only way to tell is by doing a soil test. Alkaline soils will be PH7.1 or above.
Floral & Hardy’s Top Ten Shrubs for Alkaline Soils:
While slow growing, this unusual, large, evergreen shrub will show an abundance of leathery, dark green foliage accompanied in autumn by both the flowers and, at the same time, edible, but sadly flavourless, strawberry-like fruits. No pruning is required, but try to grow it in full sun.
Ceanothus ‘Italian Skies’
The ‘Californian Lilac’ is another evergreen cultivar whose glossy, emerald foliage will be festooned with wide cones of tiny, rich blue flowers in the later weeks of spring. This cultivar isn’t as tough as the Arbutus however and as such should be planted in a sheltered position with, as its name would suggest, plenty of sunlight.
Cistus pulverentus ‘Sunset’
The ‘Rock Rose’ is a low growing species of shrub and continues the run of evergreens on our list, but with magenta pink, saucer-shaped flowers possessed of bright yellow stamens in early summer. Once again ‘Sunset’ needs a sheltered position in full sun.
Deutzia ‘Pride of Rochester’
The ‘Pride of Rochester’ enters the running as the first deciduous cultivar. It is a medium-sized shrub with an upright habit, its pea- green foliage grows on long arching stems, and this will be coupled with dense clusters of small pink flowers running the entire length of the stems in June. To keep it flowering well, prune back shoots which have flowered once flowering has finished.
Fucshia magellanica ‘Riccartonii’
Among the more exotic-looking species mentioned we have the ‘Riccartonii’ – another upright deciduous shrub, though this cultivar is hung with complex, beautiful ,crimson and purple flowers from summer to autumn. In harsh winters frost may kill off the top growth, but don’t worry, cut the stems back to within a few centimetres of the ground in March.
Kerria japonica ‘Pleniflora’
‘Plenifora’ is a tall, vigorous shrub with arching stems and toothed green foliage. The cheerful, double, golden-yellow, pom-pom-like flowers appear from April to May. In June prune back the shoots which have flowered.
English Lavender is a fairly common sight so I won’t bore you with a description, except to say that ‘Hidcote’ has particularly deep purple flowers over a long flowering season. It needs a moderately fertile soil with full exposure to sunlight and make sure you deadhead the obsolete flowers every autumn to ensure healthy growth.
This aromatic small shrub has evergreen foliage and a compact growth habit. The foliage is a soft grey-green and will be offset by the plant’s yellow, button-like flowers in summer. They are susceptible to strong winds and should therefore be provided support or shelter. Also, trim over once flowering has finished in order to maintain a neat shape.
Syringa ‘Charles Joly’
An upright and elegant variety of Lilac, ‘Charles Joly’ is a deciduous cultivar with heart-shaped green foliage and scented, purple flowers from May to July. Lilacs are a very hardy species and will only require a minimal amount of maintenance in the form of cutting out any untidy branches once the flowers have faded.
Weigela ‘Wine and Roses’
Finally we have the ‘Wine and Roses’, in the titular sense anyway, whose deep pink, trumpet-shaped flowers will be on display from May to August, complemented well by the deep purple foliage. Despite their bombastic blooms, they’re also surprisingly hardy and will tolerate more or less any soil conditions. Once again, give them a prune once all the flowers have gone over.
Next week we’ll be covering another plant that prefers an alkaline soil – Clematis – and looking at a number of different varieties which, when grown in unison, can bloom in sequence providing a year-round source of vibrancy.
By Josh Ellison