Use water plants with contrasting shapes to create appealing compositions
Water, cupped in a container or basin, is a thing of beauty. Its flickering reflections are a welcome presence in any garden. But dressing it up with plants transports the display to a whole new dimension. I like to create compositions that are vibrant and dynamic, so I use plants with contrasting shapes, colours, and sizes. For me, the more contrast, the better.
I like to combine the tall, slender, spiky shapes of an erect, fine-leaved marginal plant like yellow flag iris (Iris pseudacorus) or sweet flag (Acorus gramineus) with the floating foliage of an easy-to-grow water lily (nymphaea sp) or some of the smaller lily-like plants such as Showy Marshwort (Nymphoides spinulosperma) and Nardoo (Marlilea mutica). Bare in mind, water lilies will be too big for most water bowls, so it may be better to stick to the latter 2 varieties and other small floating varieties.
As an especially dramatic accent, I might add a Papyrus or a clump of brightly colored chameleon plant (Houttuynia cordata 'Chameleon'). I especially like using plants that have a story of their own: pitcher plants (Sarracenia spp.), for example, eat insects, digesting small bugs in the recesses of their large, trumpet-shaped leaves.
To finish off a planting, I sprinkle a few small floating plants -- like water lettuce (Pistia stratiotes) or water hyacinth (Eichhornia crassipes)-over the surface of the water. I also might soften the hard edge of the container by letting a cascading plant like water mint (Mentha aquatica), with its fragrant foliage and powder-blue flowers, tumble over the side.
Whatever plants I use, I try to keep them in scale with the container. Huge plants spilling out of a tiny container most likely would not create a pleasing effect. There are no strict guidelines to follow, so I just aim for a plant and container combination that looks harmonious and proportionate.
For a crisp look, use only a few water plants
The first mistake beginning water gardeners make is jamming too many plants into their container. Though a water bowl easily accommodates up to four plants potted in 140mm and 200mm pots and a host of floating plants, there's no need to use that many. An overcrowded container often results in designs that are chaotic. Keep it simple. Especially when you're starting, it's easiest to make pleasing designs with only two or three plants. As you gain experience, you can graduate to more complicated compositions using greater numbers and varieties of plants.
However many you use, how and where you place plants in the container is of paramount importance. The plants should fit as a unit to create the picture you want. First, determine how the planting will be viewed. Designing a container that will be seen from a few directions is a lot easier than making one that's meant to be viewed from all sides.
Unless the container is to be seen from all around, place a tall, spiky plant at the centre rear to create a dramatic backdrop. Then use a broad-leaved marginal or two in front or to one side, where their generously sized leaves will contrast sharply with the whip-like fronds of taller plants. Remember to keep it simple, otherwise you risk diminishing the effect. For containers that will be seen from all sides, I put the tall, vertical-leaved plant in the middle and arrange broadleafs on each side.
For either kind of design, I arrange and rearrange the plants until I get the effect I'm looking for. It's easy to change the height and position of plants by perching them on bricks or empty, overturned containers. Most marginals, whether their leaves are thin and vertical or broad and horizontal, give excellent results when their crowns are placed 6 inches or less beneath the water's surface. Only after the main parts have been positioned do I begin adding accents like floating or cascading plants, or for a special touch, an eye-catching specimen.