Garden Design (2015)
Waterside planting
Successions of aquatic plants positioned on submerged terraces emerge from ever deepening water, fusing the planting design of the pond with the surrounding borders on drier ground.
DESIGN BY IAN KITSON
THRIVING IN DAMP soil or paddling at the edges of a pool, waterside planting lends a colourful fringe around features and invites an abundance of wildlife to the party too. Water lilies and other aquatics add to the drama, their exquisite flowers decorating the glassy surface.
Plants for pools and ponds
One of the most exciting elements in a garden, water is frequently used in isolation to create drama and atmosphere, but features that also include aquatic and bankside plantings have a character all their own. Lush, exuberant idylls, they conjure a sense of surprise in a garden, like stumbling on a desert oasis. The diversity of plants available is as astonishing and rich as for any other aspect of the garden, with plants to suit every style, from large lakes to tiny patio water features. If carefully chosen, aquatics can be used to great effect in formal and geometric designs as well as more naturalistic settings.
If you want to include aquatic planting, design a feature that can accommodate your favourites, with varying water depths and conditions that will suit the different plant groups. Create deep areas for water lilies (Nymphaea), whose rootstocks and stems must be submerged, while their leaves and flowers float on the surface. Marginal plants grow on the bankside: some, like the vigorous flag irises (Iris pseudacorus), are happy with their roots submerged, others, including Iris ensata, prefer to be just below the surface, while a third type, Iris sibirica, thrive with their roots just dipped in water or in boggy soil. Floating aquatics, including the water pineapple (Stratiotes aloides), live a sedentary life partially submerged or floating on the surface. Moisture-loving perennial plants, including skunk cabbage (Lysichiton) and many primulas, are ideal for the boggy areas around a natural pond, where the soil is permanently saturated or wet for much of the year. These bog plants can be grouped to create a lush and leafy fringe around the water’s edge.
“Reflections are extremely valuable in winter and tall vertical structure is essential. Include reeds and rushes, such as the skeletal deciduous forms of Phragmites australis, or evergreens like Carex morrowii. I also plant Viburnum opulus; its cherry-red berries persist in winter, as birds only feast on them when times are tough.”
THOMAS HOBLYN
Designing with flowers and foliage
The largest group of aquatics are the marginal plants, which offer a wide range of flower colours and forms. Choose a range that flowers at different times to maintain interest, starting in spring with Caltha and Lysichiton, and following on in summer with irises, Lychnis and water lilies, amongst others, with the rushes, such as Typha, providing autumn interest. Bog plants can be used to fill lulls in the pond planting. Although many water plants have outstanding flowers, many have equally beautiful foliage, which can be used to create a variety of effects. For example, an imposing clump of a single species, such as the vividly striped sword-like Iris pseudacorus ‘Variegata’ or parasol-leaved Darmera peltata, will provide architectural accents. For a minimalist look, try clumps of a single variety of Japanese water iris (Iris ensata), or mix complementary flower types to create a slight variation in tone, but parity in leaf form. Moisture-loving plants also lend a luxuriance that may not be present in other parts of the garden. Giant-leafed perennial colossi, such as the Chilean rhubarb (Gunnera manicata) and ornamental rhubarb (Rheum palmatum) love moist soil, and produce leaves that are often an arm-span or more across.
PLANTING POND PERIMETERS
The design of a pond and type of planting used exerts huge influence over the character of the surrounding garden. A feature with gently sloping sides will allow bog plants and marginals to merge seamlessly from the damp soil on the banks to water up to 45cm (18in) deep, creating a gradual, dream-like transition. A steeper slope or sudden drop will truncate the effect, creating a more definite edge or line.
An artificial pond will not necessarily have boggy margins but you can create a marshy area. Dig a hole at least 60cm (2ft) deep beside your pond and line it with butyl or similar pond liner. Pierce the liner with a few holes, add a layer of grit, and then refill with the excavated soil mixed with well-rotted compost. Water the bog regularly during dry spells.
CULTIVATION NOTES
When designing your pond, include shelves around the edges to accommodate marginal plants and a deeper area in the centre for aquatics, such as water lilies. For details on how to construct a pond, see p.87.
It is best to fill your water feature with rainwater, rather than from the mains, as it is better for wildlife and the ecological balance in the pond. Levels will need to be maintained during the summer, using water from a butt if possible during dry spells or adding mains water gradually so that it does not change the temperature too rapidly.
You can either create a planting bed at the bottom of the pond with a layer of garden soil, or contain your plants in pond baskets filled with garden soil or aquatic compost - do not use potting composts as they are too rich in nutrients and will encourage weeds. A mulch of gravel will help to keep the soil or compost in place. If you did not create the pond yourself and it does not include shelves or shallow areas, you can still include marginals by planting them in baskets and propping them up on bricks. Include oxygenating plants, such as Ceratophyllum demersum, checking that those you plan to use are not invasive species and causing problems in the wild, some of which are still available to buy. Most aquatic plants need to be lifted and divided every few years to rejuvenate them and maintain flowering.
Waterside plants
BOG PLANTS: Astilbe species; Darmera peltata; Eupatorium cannabinum; Gunnera manicata; Iris sibirica varieties; Osmunda regalis; Primula pulverulenta; Primula florindae; Rodgersia species; Rheum palmatum
MARGINALS AND AQUATICS: Caltha palustris; Iris ensata varieties; Iris pseudacorus ‘Variegata’; Lobelia cardinalis; Lychnis flos-cuculi; Lysichiton americanus and L. camtschatcensis; Nymphaea varieties; Orontium aquaticum; Schoenoplectus tabernaemontani ‘Zebrinus’; Typha latifolia ‘Variegata’, Typha minima; Zantedeschia aethiopica ‘Crowborough’ and other varieties
A stream’s edging of understated perennials, annual daisies and ferns enhances the naturalistic design.
DESIGN BY FIONA STEPHENSON
Rich and diverse poolside planting helps anchor a water feature into the landscape and controls the views across the water surface.
DESIGN BY ACRES WILD
The angle of the bank and depth of water in a pond will influence the range of plants you can grow, with some large water lilies requiring water one metre (3ft) deep or more to thrive.
DESIGN BY JAMES SCOTT
An enchanting partnership of water irises and flowering rush (Butomus umbellatus).
DESIGN BY ACRES WILD
Parasol-leaved Damera peltata and yellow Caltha palustris luxuriate in damp soil.
DESIGN BY ARABELLA LENNOX-BOYD
Boldly-detailed steps and exuberant waterside planting herald a dramatic natural pond.
DESIGN BY THOMAS HOBLYN
In small ponds, plant in baskets filled with aquatic compost and cover with gravel.
DESIGN BY WILSON MCWILLIAM