Marginal Plants for a Goldfish Pond
What is a Marginal?
A marginal plant is not a species of pond plant; they are a group of species of pond plants that grow in the marginal areas. Marginal plants are semi aquatic plants that grow in shallow waters or in wet soil around the waters edge. They are pond plants that grow mainly out of the water but have their roots or lower halves submerged in water or wet soil. Goldfish pond designers who wish to incorporate marginal plants design a marginal shelf at a depth of 2-12 inches. As the slope of the pond drops, a terrace is added to plant or place potted marginals.
Marginal pond plants serve several functions for a goldfish pond. For one, they make the goldfish pond look nice. With the various species of marginals that grow tall, spread out, fill in or flower, a goldfish pond designer has the potential to create a beautiful space. By placing the tall growing marginals in the back and the low growing marginals that spread out along the waters surface, many layers of depth can be created.
Goldfish predators are another reason for planting marginal plants around a goldfish pond. Many animals including blue herons, raccoons and coyotes will catch and eat goldfish if they can get at them. Marginals create a buffer and eliminate the shallow areas where these predators like to hunt.
In the summer months, an outdoor goldfish pond that receives a lot of direct sunlight can raise the water temperature above what a goldfish prefers. Marginal pond plants can cast a shadow and create shade for the goldfish to seek relief in. Adding more shade to a goldfish pond will help regulate the water temperature of the entire pond.
Outdoor goldfish ponds for several reasons tend to have a lot of nutrients (nitrates) in the water. High levels of nitrates can cause and outbreak of pond algae or cause problems for goldfish. Marginal plants do a great job of using up this excess of of nutrients and eliminating elevated levels of nitrates from the goldfish pond water.
Marginals for Goldfish Ponds
- Sweet Flag
- Asthma Weed
- Water Iris
Care for Marginal Pond Plants
Plant each marginal plant at the depth they prefer to ensure a optimal growth. Marginal pond plants are best grown in pots or baskets to make them easier to maintain and avoid roots rupturing a pond liner. Cut back tall marginals before planting to keep the foliage in proportion with their root structure. Cutting back encourages a marginal to grow thicker and fuller which is a desirable look. Make cuts above the water line on hollow shoot marginals to avoid rotting. Fertilize during growing season for best results. Cut back to one inch above the substrate for winterizing, with the exception of cattails that can be cut back in the Spring. Overcrowded marginal pond plants can be pulled up and divided during spring when they have yet to grow back. Iris are an exception; these can be divided during the summer after they have flowered. When marginals are divided it’s recommended to trim back the roots before re-potting. Each divided marginal plant should consist of at least a substantial bud or shoot and a small cluster of roots.
Reviewed By: Tim Winter
Tim Winter has a strong affection for pets and wildlife. His years of experience caring for various types of pets has led him to share his knowledge with others on the best practices in pet care. Tim holds a Bachelor of Science from the University of Oregon School of Journalism and Communications.