Soils with poor drainage or sites with a high water table may be prone to flooding
Flooding, especially if caused by short bursts of heavy rainfall, may not last long
Flood-prone soils may also experience periods of drought
James Lawrence, RHS Principal Horticultural Advisor, has designed this simple, attractive, and most importantly, sustainable border design for you to try at home with plants that are easy to grow, widely available and look good together.
This planting design recommends a range of plants that, once established, will cope in soils that may experience periods of flooding. A simple planting plan helps to create depth, interest and good coverage in a border.
The pinkish-silvery catkins of the Salix and the yellow-green stems of the Cornus provide interest throughout winter. The Aruncus and Rodgersia provide creamy-white and pale pink flowers during summer, which follow on from the bright colours of the spring-flowering Primula.
Dense planting will help prevent erosion of bare soil. The ground cover can also help to reduce soil surface moisture evaporation during dry seasons, and suppress weed growth. Additional organic mulching , preferably with homemade compost , will improve the structure and drainage of soils.
1 - Salix gracilistyla 'Mount Aso' is a shrub grown primarily for its striking catkins. In winter and early spring, before the leaves emerge, the stems are covered with soft, fuzzy pink catkins.
2 - Physocarpus opulifolius 'Diabolo' is a deciduous shrub with deep purple, three-lobed leaves and clusters of small white, pink-tinged flowers in summer.
3 - Cornus sericea 'Bud's Yellow' is a dogwood with bright greenish-yellow winter stems. The green leaves often develop yellow autumn tints before falling.
4 - Aruncus dioicus is a tall herbaceous , forming a clump of long leaves composed of numerous opposite leaflets that often develop attractive yellow and orange autumn colour. In summer, feathery plumes of tiny, white flowers are held on stems above the foliage.
5 - Rodgersia pinnata is a clump-forming perennial with large, divided, bronze-tinted young leaves that mature to rich green. In summer, tall plumes of small pink to creamy-white flowers rise above the foliage.
6 - Primula Candelabra hybrids are herbaceous perennials with leaves in basal , and flowerheads with layered whorls of flowers in shades of pink, red, purple, yellow, orange, or white in late spring and early summer.
Periods of flooding can be brief and may be caused by heavy downpours, high water tables, compacted soil or poorly drained soil (often clay ). By choosing plants which are well-suited to tolerate periods of flooding , you can keep your border looking good and growing well, because plants that are planted in the right place tend to be stronger and more naturally resistant to pests and diseases. Also, once the plants are established, this will reduce the need for extra inputs that less well-adapted plants would need, such as fertiliser and watering in summer.
Saturated soil limits the ability of plant roots to breathe. Short periods of flooding may limit root growth, but longer periods can cause roots to die and rot. Some plants have evolved to cope with periods of flooding as well as drier soil conditions.
The annual addition of garden or other organic matter will gradually improve the structure and drainage of your soil.
Using the ethos of ‘right plant, right place’ to create a sustainable planting combination is great for the environment. It helps avoid waste and the use of products and practices needed to try and help ailing plants, such as the application of fertiliser. It also creates robust, long-lived planting that benefits soil health and garden . For more information about sustainable gardening, please see the RHS Sustainability Strategy .
