Guide to the Best Marginal Plants to Use in a Water Garden

Marginal plants change the appearance of a water garden drastically, so it is very important to include several different varieties in and around your own pond. Because of the nature of man made water gardens, there are several plants that work well in a natural pond, but will not adapt to a homemade water garden environment. Therefore, it is important to choose the best marginal plants for your water garden.

Marginal plants are meant to be near the edge of a pond, growing in small baskets or containers. Several marginal plants also do very well in shallow, slow moving stream. If you have a stream element in your water garden, make sure to include some marginal plants along the edge of the stream to create an interesting landscape.

Here are some of my favorites and the best marginal plants for a water garden.

Marsh marigold
Marsh marigold is often referred to as cowslip, and is a very common marsh flower growing naturally in a huge number of hardy zones. The marsh marigold is a great pond addition because of its huge, bright yellow flowers and broad deep green leaves. The plant multiplies nicely in a controlled water garden habitat, it does not spread out of control, but it will give you enough plants over the years to divide nicely and add to other areas.

Marsh marigold grows best in full to partial sun. I have a shaded portion of my water garden where the marsh marigold does fine-- just with fewer and smaller blooms. Stream locations, with the plant placed towards the edge and among rocks where roots can grab on, are excellent locations. Also, basket plantings along the edge of a shallow garden are ideal.

Water Mint
Like regular garden mint varieties, water mint spreads very quickly in whatever setting you decide to add it to. With a little care though, it is easy to maintain and keep from taking over the rest of your water garden. Plant water mint in closed containers, meaning a plastic pot with no openings, besides the top, and away from any loose soil that may be in your pond. In addition to the tall spikes, water mint flowers and adds a nice fragrance to your water garden.

Sweet Flag
Sweet flag is a great marginal plant to add vertical distinction to your garden, especially when most of the plants that are found in the water are broad leafed or creepers. Sweet flag is an upright spiky plant that has both flowers and berries, later in the season of course, making it a very interesting addition. This marginal plant is very hardy and a perennial, so as long as you take the necessary precautions to prepare it for the winter months, you should see it again in the Spring.

Blue Flag Iris
Because of the way Blue Flag Iris grows, it is best to plant it in a basket and add it to the edge of your water garden so that just the roots of the plant are under water. This is not one of the marginal plants that likes to be entirely submerged, but still enjoys and thrives in the water. Blue Flag Iris flowers so it requires a decent amount of sunshine during the day and if stored indoors over the summer, or replanted in the ground, it will return the following year. If you are lucky your iris will grow additional clumps that can be divided and placed in other parts of your water garden.