The Complete Swell Guide to Planting Your Pond

Before you even consider buying pond plants, the key to success is to first understand the types of pond plants which can be added. There are 5 key types of aquatic plants: Bog plants, Marginals, Deepwater plants, Floating plants, and Oxygenating plants, all which sit at varying depths within the pond as well as have different methods of planting.

Plants make for an excellent addition to garden ponds due to their ability to encourage wildlife to visit your pond, aesthetic qualities in the form of green leaves and bright flowers, as well as having nitrate reducing and oxygenating functions.

For these reasons both old and new ponds will benefit from the addition of plants, as they also provide shade to reduce green water and protect fish as they provide cover from predators.

Aquatic plant selection can seem like a daunting task to begin with, but with our simple guide we make this a little easier when you decide to buy pond plants. Planting depth is the most important factor when it comes to choosing suitable plants to add, as selecting a plant which is ideal for placing on a shallow shelf and placing this on the bottom of the pond isn’t going to produce the results you desire.

Here at Swell, we offer an extensive range of live plants and 'do it yourself' kits to turn your pond into an area of visual interest in your garden.

The easiest way to select the correct type of plant, is to break your pond down into zones depending on depth.

Zone 1 is best described as the edge of the pond, where the ground is damp but not completely waterlogged. Bog plants are ideal for edging a pond as they thrive in a moist soil environment without complete submersion. Species of Iris and Primula are ideal for adding to bog gardens surrounding your pond.

This area is constructed by digging out the ground, so the pond can spill over into an area of aquatic compost. Bog plants can also be potted in an aquatic basket which is lined with a hessian square, filled with aquatic compost and topped with gravel but only having the bottom of the pots covered by water.

Zone 2 can be categorised by an area of shallow water which is up to 25cm (10 inches) underwater. Marginal plants are excellent for providing colour and vibrancy around your pond throughout the spring and into late summer, as native species such as Iris, Bullrushes and Marsh Marigold produce bright yellow, blue and lilac flowers.

Unlike bog plants, marginals are almost always potted in pond baskets which are completely submerged. They also help to reduce nitrates within the pond, which aids with algae control thus contributing to water clarity. This is usually achieved by digging a shelf into the structure of the pond before laying your liner.

Zone 3 is the area within your pond which exceeds 40cm in depth. The most well-known deep water plants are Water Lilies and Water Hawthorn both of which give different looks to your pond, while giving shade to reduce light levels, therefore aiding in algae prevention.

Lilies produce larger, brighter colours such as pink flowers with broad leaves, while Water Hawthorn gives more delicate, small white flowers. Both have the same care requirements; it is purely down to aesthetic preference as to which you choose.

Planting deep water plants is exactly the same as Marginals by placing these in a plant basket on the bottom of your pond. Once placed in a pond basket, it is best to slowly lower the plant instead of placing this straight on the bottom of your pond.

You may need to elevate these using bricks for example to begin with, to initially place the plant so it is at a depth where young leaves float on the surface, and slowly lower this bit by bit as the plant grows. The ideal final depth for larger water lily species is approximately up to 120cm (4ft), with the ideal depth for smaller species being approximately 60cm (2ft).

Zone 4 relates to an area of any depth within your pond, as floating plants never anchor their roots, so are not restricted by depth. They rest on the water surface, so much like a water lilies, floating plants such as Frogbit, Hyacinths and Water Lettuce can provide shade to help combat algae while being excellent at nitrate removal. These require no specialist planting techniques, as can simply be placed on the water’s surface.

Oxygenating plants can fall into a few zones, as there are two main ways they grow: Emersed oxygenating plants grow with foliage above the water level, and submersed grow with foliage below the water level. Both emerged and submerged plants produce oxygen.

Oxygenating plants work through the process of photosynthesis to create oxygen which dissolves into the water, benefiting the aquatic life and feeding the bacteria which help to keep your pond healthy and the water clear.

Examples of British native oxygenating plants include Hornwort, while Elodea densa and Pennywort can be classed as invasive non native plants. Much like marginal plants, oxygenating plants rapidly consume nitrates making these an excellent choice for your pond.