Heavy soil may only be waterlogged when rainfall is heavy, or it may persist throughout the year. Clay soils are particularly prone to this; their tiny particles stick closely together, trapping water and excluding air. The problem is worse where soil has been compacted, perhaps during building and construction. New home owners often discover this when they come to plant the garden.
This blog is supplementary reading for my Shrubs course. Join me in the online classroom and choose the right shrubs for your planting design.
Of course heavy soil can be improved by adding organic matter or grit to aid drainage, however in many situations it is simply better to plant subjects which thrive with wet feet. Some of the loveliest deciduous shrubs will contribute years of colour when planted on wet soil, most of them coping with the dry conditions which follow in periods of summer drought.
1. The dogwoods, grown for their foliage and colourful winter stems, are reliable favourites. All of the red barked dogwoods thrive on wet clay soils. Cornus alba ‘Sibirica Variegata’ is a great choice for smaller gardens; it grows to only a metre or so in height and spread. The attractive green and white variegated leaves take on shades of pink and purple in autumn, before they fall to reveal dark red stems. Truly a plant for all seasons, it rarely needs cutting back.
2. Cornus sericea ‘Hedgerows Gold’ is a strong growing variety of the red osier dogwood reaching 2 metres or more. The green and gold variegated leaves colour richly in fall, revealing green and red stems that can be pruned hard in spring to control size, or left to grow even taller and broader. A real splash of colour and a great choice where quick results are needed.
3. Deutzia ‘Strawberry Fields’ is a delightful flowering shrub producing clusters of strawberry pink blooms in mid-summer on the arching branches.A reliable performer it thrives on clay, but also in quite dry conditions in sun or semi-shade.Cut back some of the flowered stems when the blooms fade and let the new shoots develop naturally to bloom the following year. It makes a lovely backdrop to a border and will easily reach 2 metres or more.
4. As the name suggests hydrangeas love water and few shrubs give such a long-lasting and colourful floral display. Hydrangea macrophylla ‘Zorro’ has the benefit of black stems which add interest among the lush green leaves. The lace-cap flower heads are held well above the foliage in summer and remain attractive well into autumn.Mauve-pink on alkaline soils, or rich blue in acid conditions, it is at its best on permanently moist ground.Grow it in semi-shade to bring colour to a dull corner.
5. Leycesteria Formosa ‘Golden Lanterns’ is a golden-leaved form of the pheasant berry, a vigorous shrub found naturalised by water in many areas of Europe. The arching, green stems carry hanging clusters of deep red bracts with small white flowers that are followed by shining berries in late summer. One of the easiest shrubs to grow it will thrive in the wettest conditions in sun or shade.The bright foliage makes a welcome highlight amongst green leaves.
6. Physocarpus opulifolius ‘Diablo’, with rich purple black foliage is a lovely form of the North American ninebark. A very hardy shrub that thrives in just about any conditions that will grow quickly to 2 metres or more. Pretty pinkish-white flower clusters develop into small red fruits that garland the arching stems in summer. A good shrub for cutting with the benefit of attractive tan coloured winter stems with peeling bark.
7. Rosa gallica ‘Officinalis’, the apothecary’s rose is perhaps the oldest rose in cultivation and one of the toughest and most tolerant.It only flowers once, for a long period in midsummer, but it is wonderfully fragrant, disease free and much loves by bees.Roses love clay soils and like plenty of water so they are always a good bet for heavy wet ground, providing that you feed them generously.
8. Sambucus racemosa ‘Sutherland Gold’, a golden-leaved elderberry has delightful lace-edged golden leaves on vigorous, upright shoots.Like most of the elders it grows quickly and soon makes an impact. Hard pruning in the first two winters after planting stimulates strong growth and lush foliage.‘Sutherland Gold’ is more sun tolerant than other golden-leaved elders but may scorch on dry soils; wet conditions are perfect.
9. Sorbaria ‘Sem’ is a great choice where space is more limited. It forms a suckering clump of upright stems up to a metre or so in height. The fern like leaves are soft yellow in spring, orange at the tips of the shoots. They fade to green in summer and the fluffy cream flower heads appear. An easy shrub that needs no pruning and grows best on heavy, wet soil.
10. Spiraea ‘Anthony Waterer’ is one of the taller spiraeas. With heads of tiny crimson flowers above dark green leaves in summer, it is an excellent subject to plant in small groups, or repeat through a planting scheme. It grows to less than a metre in height.A light clip with shears in winter keeps the plants compact and removes faded flower heads.
When planting on heavy, wet soil use boards to stand on and avoid compacting the ground further by firming plants in with too much pressure. Grit spread on the soil surface will help to keep soil splash off the lower foliage and really helps young plants in extreme conditions.
Other good shrubs for wet soil include:
Lonicera x purpusii ‘Winter Beauty’
Magnolia x soulangeana
Salix gracistyla ‘ Mount Aso’
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