Choosing Plants for Your Water Feature

Selecting plants for a water feature is a very personal matter, but there are many aesthetic and cultural aspects to consider when making a choice. It is important to make an early decision about the cultural methods to be used. If you grow your plants within the pool in aquatic planting baskets, the options for successful cultivation will be increased, even if it will be marginally more difficult to make the arrangement look natural. Planting baskets will make it much easier to control the development of your plants. Where necessary, such as with the acid loving cotton grass (Eriophorum angustifolium), they also make it possible to create special soil conditions in isolation from the other plants.

 

SELECTING FOR EASY MANAGEMENT

As with most garden features, the management of a water garden can be made simple or complex, depending upon the plants that are grown. By carefully selecting plants that do not creep about or seed themselves freely, caring for the water garden can be greatly simplified.

The most amenable plants are those that remain in orderly clumps, like marsh marigolds, the pendulous pond sedge (Carex pendula) and the more modest growing irises, such as Iris laevigata, I. versicolor and their varieties. None of these creates undue difficulties with self seeding either.

The pickerel (Pontederia cordata) is well behaved, so too is the flowering rush (Butomus umbellatus). Indeed, both are so easy-going and restrained that they are among the few marginal plants that could be tried together in the same basket. They have contrasting habits, but flower in harmony, the pickerel with a blue flower spike and the flowering rush a rose-pink umbel. In general, joint planting is not to be recommended, except where upright spiky rushes would look better with some basal softening, using a creeping aquatic  like the brooklime.

Staking is not practical in most pools, so it is essential to assess the exposure of the plants to strong winds. Resist growing tall subjects if they are likely to suffer from wind damage. In draughty places, tall marginal plants growing in containers may be blown over into the water, unless secured, and constantly look drab. They will often pick up algae and debris from the water and will need careful regular manicuring. Shorter, more stable, plants are the practical answer, although in some situations, this may cause the aesthetics of the feature to suffer through a lack of height.

Pests and diseases are relatively few and far between. Waterlily aphids are probably the worst and are quite indiscriminate, feeding on any succulent plants that take their fancy. Waterlilies are the obvious target, but Butomus umbellatus and the arrowheads, or sagittaria, are also great attractions. Where this pest is a constant nuisance, do not grow butomus or sagittaria, although you may still find it on other aquatics. For the most part, selecting plants upon their susceptibility, or otherwise, to predators is not necessary, as in a well ordered pond, natural controls will be maintained.

 

SELECTING FOR FLOWERING PERIOD

During the winter, the pool will be dead, and the only chance of creating any interest at all will rest with the skeletal remains of the flower heads of plants like the water plantain. These can be most attractive, especially after a snowfall, but their durability cannot be depended upon.

The first flowers in the water garden are usually provided by the marsh marigolds, especially the common Caltha palustris and its double-flowered variety ‘Fiore Pleno’. In the adjacent bog area, Primula rosea produces its bright pink flowers alongside the bold white or lilac-blue drumstick heads of P. denticulate. These are followed by the brilliant mixed colours of the Iris ensata hybrids and, in the margin of the pool, the Iris laevigata varieties.

At about this time, the waterlilies start to blossom, becoming the focal point for the pool and remaining until late summer. Alongside them, the various reeds and rushes push up their brownish flowers, while the yellow musk and brass buttons add splashes of gold. Pontederia and butomus bring up the rear, the water dock (Rumex hydrolapathum) taking the water garden into autumn with its bright red and coppery foliage tints.

 

FOLIAGE EFFECTS

Apart from the water dock with its bright autumn colours, very few aquatics create a leafy spectacle, although among the great diversity of marginal and bog garden plants there are myriad handsome foliage plants. A number of these are quite exotic-looking, while others arc more comfortably natural. Consequently, they may require careful selection if you are to achieve the desired effect.

Darmera peltata is one of the best examples. It is a super plant for a water garden where hostas abound, but a square peg in a round hole when it comes to the wildlife pool. Here, the graceful pendulus sedge, Joe-pye-weed (Eupatorium purpureum) and meadow sweet are more appropriate.

If the pool is small and well manicured, it will never look completely natural. It will always be a garden pool, so you will be able to get away with mixing and matching foliage contrasts, and also use them effectively to disguise the fading remains of early plants. The great shuttlecock-like crowns of the ostrich feather fern (Matteuccia struthiopteris) are perfect for hiding the fading blossoms of marsh marigolds and early primulas, then creating a beautiful soft green foliage effect themselves. They have the added advantage of not only being excellent bog garden plants, but also being tolerant of living in shallow standing water.