We are all seeing the demand for constructed wetlands in commercial and residential landscape construction. Please don’t see it as a chore that you dread, a requirement by a governmental body that you know you'll have to do. Please consider: Why else?We are all seeing the demand for constructed wetlands in commercial and residential landscape construction. Please don’t see it as a chore that you dread, a requirement by a governmental body that you know you'll have to do. Please consider: Why else?
Storm water can be caught and controlled in an earthen tank. Sediment is the main pollutant in all waterways. Sediment is held and carried by running water. Still water drops its load. Captured runoff water can be metered out over time and thus mitigate flood potential. A simple recirculation pump that shoots the water into the air for oxidation does a lot to improve the quality. If that is enough, Fine. Build a tank around back of the facility, weed-eat it out once a week, and fence it off. This is a way of storm water management but it misses another way out.
If, however, you want to do more than just control the water; if you want to clean the water more than just the sediment; if you want to get at the nutrient loads; if you want to create a landscape attraction; you need an active constructed wetland habitat. You need to design and build a facility with places for flowering, fruiting greenery. You need a functioning eco-system with wildlife. You need intelligent maintenance. These are the ancillary benefits that justify the apparent expenses.
Add in a boardwalks and paths, a pier with a gazebo, benches, and descriptive signage and pamphlets for the people who will be drawn to your new space. The wetland will have flora and fauna to be enjoyed. Commercial clients can have the Zoo people come and give programs to the kids on turtles while Mom shops at the home supply warehouse. You can have retired couples walking, holding hands, and watching Egrets fish every afternoon in their subdivision. You can have wildflowers and autumn color and shade. You will have the simple beauties of sparkling water and the sounds of frogs. This is an opportunity to add value to your project, not a cost item. This can be an asset, not a dread.
Two plants work extremely well in constructed wetlands and that love wet feet are SWAMP TITI Cyrilla racemiflora and BUTTONBUSH Cephalanthus occidentalis:
SWAMP CYRILLA or TITI Cyrilla racemiflora which is a large, slowly-suckering shrub to small tree that throws yellow, orange to red fall color throughout the winter from the inside of the plant and has clusters of finger-like flower racemes that set fruit and persist into winter. Right now in early summer this plant is the epicenter for bees on the honey-scented showy flowers. This plant is NOT for the formal garden. It is best used as a thicket plant, for screening and for stormwater management in natural form designs. Old specimens can reach 25 feet and become more tree-form.
Early summer flowers on Cyrilla
Early fall color on Cyrilla
BUTTONBUSH Cephanlanthus occidentalis a deciduous one with early summer flower balls that invite jealous butterfly territorial wars and lead to the "button" fall fruits. Here again a large loose shrub to small tree clump form with time. Can be pruned to clear trunk form and it holds that grooming.
Grows in standing water.
Buttonbush in flower and the constant butterflies
A natural swamp with Buttonbush in the center
Now some hints to implementation:
The essential part of getting these plants to work for you is 1) create a natural basin with distinct zones in relation to water depth with proper substrate soils and 2) maintain it.
Always include as much area in flat “shelves” in the soil profile, one just above the normal waterline and one just below it. Then select and site plants that are specific to those positions, mixing trees, shrubs and perennials at all levels.
This kind of planting is specialized; not to be bid at the last minute to the average list of landscape architects or contractors and their subsequent material suppliers.
The best way is to start early and do the research to find the people who can assist you. The more time for planning and material assimilation the better!
Please develop the idea of the storm water system as a garden that will benefit the environment through physical and biological methods and it will give the human bystanders a treat as well.
And as I will always close: