Shape and Size
Once you’re satisfied with the location for your pond, it’s time to nail down its shape and size. Rectangular ponds found in modern or minimalist styles offer a clean, relaxing view and often mesh well with a home’s architectural style. However, water flow around sharp corners can be impeded and allow the main water flow to bypass without mixing. These stagnant areas will eventually create dead spots where anaerobic bacteria and algae can get foothold. If the formal squared corners appeal to you, you might consider adding a pump to maintain a vigorous water flow. Another stylish example is a hexagonal pond. Its shape is close enough to round that water can move unimpeded, but it still features clean lines and a modern look.
Circular or oval ponds are unlikely to develop stagnant corners and will easily enjoy efficient water flow throughout. Irregularly shaped ponds, such as those used for a more natural look, lie somewhere in the middle. A lot of small details and intricate borders create the potential for dead spots, and they may be more difficult to address than a simple rectangle. A natural pond will do fine with an irregular shape, and if you want more intricately shaped borders, consider adding planting shelves and small marginal plants to create the outline you want.
Depth and Shelves
A decorative pond that’s focused on plants and wildlife will need to have some way of providing different depths for a variety of plant zones. If you plan to include fish like koi or goldfish, there are more requirements to take into consideration. Different types of wildlife will all have their own needs. Sounds like a lot, doesn’t it?
Let’s set some guidelines to help you identify what elements you want to include, based on your goals for the pond.
- If you’re planning on hosting fish, especially large fish like koi, you’ll need a pond that’s at least 3’ deep so the fish can hide from predators, escape warmer surface waters during hot weather, and have a safe environment if they’re overwintering where the pond surface will freeze. Plenty of floating plants will help with the shade and warm temperatures, but overwintering depth isn’t negotiable if you live in a cold winter climate.
- A pond without fish doesn’t need to be nearly as deep, especially since the oxygen demands will be lower and you won’t necessarily need to include submerged aquatic plants. In this case, a pond between 12” and 24” will work, but remember that the shallower your pond is, the more quickly the water will heat up and evaporate.
- Submerged plants like water lily or lotus can keep the water cool and counteract a lot of evaporation, but they also have different needs when it comes to depth. Pygmy Water Lily (Nymphaea Pygmaea alba) likes water that reaches 6-10 inches from the top of their pot, while standard specimens prefer a depth of 12-24 inches in order to flower well. Mature lilies, on the other hand, do best between 18 and 30 inches. If you’re planning on growing lilies, it’s probably best to aim for a pond around 2 feet deep.
- Marginal plants prefer to have their roots and the crown of the plant completely submersed under water, so set up your plant shelves to give them about 6” of water over the top of their pot.
- Some emergent plants prefer water as deep as 16 inches, while others are perfectly happy in a boggy space where they grow in soggy soil on the outside edge of the pond. Check with your plant supplier to verify the needs of a particular specimen.
If your goal is to have a pond featuring a wide diversity of plants, be sure to dig your pond with several different planting depths or build supports using pots or stones along the borders of the pond. Include native plants from each growing zone to promote biodiversity and support local wildlife who may be suffering from habitat loss.
Rocks are our Friends
When you’re adding the final details to your pond, try to add a variety of rocks and stone in the pond itself and along the edges. Rocks of various sizes, especially if interspersed with shallow emergent plants and small landscaping plants will disguise the edges of your pond and help it blend more into the landscape. In more formal installations, flagstones are an elegant touch that can also extend into the water.
Rocks, rounded stones, and gravel all provide important habitat for organisms like beneficial bacteria and tiny crustaceans. These are particularly important to maintaining the nutrient cycle in your pond, which is critical to the health of your pond.
In a wildlife pond, stones and logs can also offer a way for small creatures to access the pond for water and food and then safely exit. Turtles can often be seen sunning on rocks that emerge from the water.
