Great plants to filter pond, bog, and water garden water are vast and numerous. The jackpot of these filter plants come from the several plant families who companion well together. The Acoraceae and Araceae families that contain the taxonomically controversial an as of yet unresolved definition of the Acorus genus are among the most effective water filtration plants in water gardens.
For filtration purposes the Acorus Calamus Variegatus companions well with species in the Iris genus such as versicolor cultivars and virginica cultivars.
Acorus Americanus; Acorus Gramineus Yodo-no-yuki [ever green]; Iris (Blue Flag, the bulk common term for all iris genus cultivars of the versicolor species) Versicolor [Herb]; broad leaf ( Typha genus latifolia species) [Herb]; and narrow leaf (typha genus anustifolia species) [Herb]: All work well together as companion plants that filter ponds and water gardens very well.
The Yodo-no-yuki cultivar will add a subtle variegated yellow cream tint that is barely visible in the hue of this filterers light green spears.
This set of water filtering companions grow best in temperatures no lower than 40º Fahrenheit, in as direct sunlight as possible. Shade will not hurt this combination, sunlight just fares the filtering companions better. Theyare also great bog garden filterers also.
Some of the other most recommended filter plants listed by genus then species for ponds are Cyperus alternifolius; Eichhornia crassipes; Glyceria maxima Variegata; Juncus Afro, and Effuses cultivar (variables), Ludwigia arcuta Grandflora, and puruviana; Mentha aquatica; Oenanthe javanica Flamingo; Pistia stratiotes Aqua Velvet; Sagittaria latifolia; Scirpus; as well as those mentioned earlier in this entry.
Many water gardens have bog gardens near by. This is intentionally done so that the dense root system of the bog garden will filtrate both the bog and water garden naturally.
The addition of a pump with a rain garden or bog garden will make the plants in each will create a very effective filtration system.
For stand alone water gardens that are constructed to naturally slow drain back into the earth via a filter directly the plants mentioned and listed above are an excellent way to cut down on algae. The most affective use of these plants happens when they are in the path of flowing water so if you are running flow hoses have them filter threw the bog and back into the pond or water garden. Create a natural filtration system!