Perennial marginal aquatic plants are generally the best foundation for an Aquascape Wetland Filter. Their roots absorb excess nutrients, support biological filtration, and return year after year in climates where they are hardy.
Annual or tropical marginal plants can also be added for seasonal color and additional nutrient uptake, but they may need to be removed, replaced, or overwintered in colder climates.
Recommended perennial marginals
Good choices include:
- Pickerel rush – Strong root growth and good nutrient uptake.
- Water iris – Develops dense roots that help with biological filtration.
- Sweet flag – Hardy with a fibrous root system.
- Cardinal flower – Adds seasonal color while utilizing nutrients.
- Lizard’s tail – Performs well in wet conditions and develops a beneficial root system.
- Marsh marigold – Hardy perennial suited to shallow wet areas.
- Aquatic mint – Spreads through moist areas and utilizes available nutrients.
- Creeping Jenny – Low-growing perennial that helps naturalize wetland edges.
Aquascape notes that marginal plants provide valuable filtration by removing nutrients that could otherwise contribute to algae growth.
Can annual or tropical plants be used?
Yes. Tropical marginals such as canna, taro, and other suitable aquatic tropicals can be planted in a wetland filter during the growing season.
They can provide:
- Additional nutrient uptake.
- Seasonal color and foliage.
- Greater plant variety.
- Additional root surface area for biological activity.
In colder climates, however, tropical marginals normally will not survive winter outdoors. They can be treated as annuals and replaced each year or, depending on the plant, brought indoors for winter.
Are perennials or annuals better?
For long-term wetland filtration, hardy perennial marginals are generally the better foundation because they return each season and do not need to be replanted annually.
Annuals and tropicals are best used as a supplement rather than the only plants in the wetland.
A good approach is to:
- Use hardy perennial marginals for the permanent plant structure.
- Add tropical or annual marginals for seasonal variety and additional plant growth.
- Choose plants appropriate for the wetland's sunlight, climate, and water conditions.
Important planting consideration
Use plants with manageable root systems and control aggressive varieties.
Plants such as reeds, bulrushes, and other strongly spreading marginals may need to remain in aquatic pots to prevent excessive root growth. Aquascape recommends containing aggressive plants when necessary.
A mixture of hardy perennials with selected seasonal plants provides reliable filtration while keeping the Aquascape Wetland Filter attractive throughout the growing season.