Catch & release

As restrictions continue to limit customers’ ability to water their landscapes, and a record setting drought has hit the U.S., rainwater catchment systems are growing in popularity.

This summer, Julie Evans, vice president of The Fockele Garden Co. in Gainesville, Ga., and facilities manager David Williams, earned their accreditation from the American Rainwater Catchment Systems Association. Here, she offers her advice on getting into this sector. “The design involves so much more than just putting a tank in the ground and putting a pipe in it. If you were only an installer, you’d want a horticulture person to talk to about what’s happening in the garden,” Evans says.

She stresses the importance of understanding the nuance and cross-discipline that these systems demand.

“Typical irrigation systems that are installed are not really tuned into exactly what a plant needs. They’re more broad-stroke,” she says. Evans says that Fockele, with a strong background in plant knowledge, brings all three disciplines together – water management, plant health and construction expertise.

“If you have a landscape where you have a lot of stormwater runoff or a wet area that holds water, those are all parts of water in a landscape. Rainwater harvesting is one part of a system,” she says.

Designing the system. You can’t just install a tank with a pump and run water into it. Instead, Evans says to considers what the customer wants from the system.

How many and what kind of plantings do they have? How much water do they need? How much does it rain, and how often? Where will you draw the rainwater from? “You start at the end and go backward,” she says.

Most rainwater systems only hold enough water to reliably run dripline or small spray zones, so the rain tanks will probably run empty in the summer before they refill. “If you put rotors on an irrigation system, you’d run a tank dry.”
 

Evans says clients – and contractors – need to understand that these systems do save water, but they don’t pay for themselves. A typical commercial installation could run as high as $60,000; a smaller single-family home system would run about $2,500 she says.

Selling the system. A main selling point for Fockele is the ability of these systems, which make up about 10 percent of the company’s design/build revenue, as an integrated part of a larger construction project. to protect landscape investments even during water bans. “The city or county can be under outdoor water bans, so what are you supposed to do? How do you protect your investment?” Evans says. “The last big drought pushed people. Everybody knows water restrictions are a reality and they want to be able to keep their plants alive.”
 

A plant-based solution

Use smart plantings to capture and store rainwater in wet areas.
 

Whatever you call them -- bioretention areas, detention/retention basins, rain gardens or swales – stormwater structures all do the same thing: capture and clean water. 

And where the traditional approach to stormwater was to get it off site as fast as possible, contemporary designs aim to hold onto water – for as long as 48 hours – to avoid overwhelming natural and manmade infrastructure. 

“How do we clean the water, how do we touch the water before it gets into a pipe or natural stream?” says Eric Sauer, ASLA and principal at CYP Studios, Centerville, Ohio. “How do we get it to slow down or hold it on site?” And these structures do more than just hold runoff. They also improve water quality, improve drainage for a property, offer a place to store snow in the winter and attract beneficial wildlife. 

Design. Sauer stressed that a rain garden filled with native plantings does not have to look like a wild, unkempt prairie. In fact, the best designs are the ones that don’t look like a rain garden at all. 

“That’s a perfectly acceptable style, but a lot of people don’t like that look,” Sauer says.

His other main point to attendees was that a rain garden isn’t designed much differently than any other landscape installation. The same factors – drainage, soil pH, solar exposure, planned use – all are still relevant. “You can’t go dig a hole, plant some plants and except things to be successful,” he says. “Trial and error is not a good way to do this. You have to give it some thought.”

Here are a few questions to ask when designing a rain garden:

What’s the drainage area the system needs to handle? Is it a downspout, or a parking lot or entire subdivision?

How much water are you going to get? Try to design your system to handle the largest storm your area gets in an average year – anything larger becomes cost prohibitive.

What’s the soil like? Are you using native soils, or imported? What the garden sits in will determine your plant palate.

Where is the system installed? “Most of our failures that we see are when these are brand new.

The root systems haven’t taken hold and you get a big storm,” Sauer says.

“You’re dealing with water that the system can handle after a year, but how do we handle that until the system is established?”

Use core mats, erosion control blankets or temporary silt fences.

What’s the salt exposure? If you’re building near roadsides, or parking lots, you’ll need to take this into consideration. The right plants can tolerate high exposure to salt.

Maintenance. Just as the design of rain gardens follows traditional principles, so too does their maintenance.

You have to cut back growth in the spring, remove debris and mulch.

Areas to watch include the plants’ absorption of chemicals used on the property.

Plants used in these systems are designed to suck up a lot of water, and they’ll take up anything else, too. 

Also, the systems need a bit more attention after their initial installation.

Topsoil erosion and plant establishment are very important to make sure the system takes root successfully. 

“Erosion control is critically important on all of these,” Sauer says. 

Eric Sauer, principal at CYP Studios, Centerville, Ohio, gave the following list of trees, shrubs and perennials that perform well in rain gardens.

Trees
Swamp White Oak – Very tolerant. A street tree that is rough at first like ginkgos, but becomes very attractive. It’s tolerant of moist and dry conditions, does have acorns.

Bald Cypress – Not for pocket rain gardens, but an overall large scale development-wide system, this tree is a beautiful tree, can grow standing in water and turns red in the fall

River Birch – They don’t like to dry out; will drop leaves in the summer.

Sycamore – Does fruit, but the bark texture as it ages is very attractive. Works as an urban tree, and is underused.

Black Gum – Slow growing, hard to transplant and hard to get big specimens. Good especially in parking lots, great red color in the fall.

Small trees and large shrubs
Sweetbay Magnolia – Flowers off and on in summer

Pagoda Dogwood – Remeber, not everything has to be native; it can be adaptive.

Serviceberry – Delicious fruit

Witch Hazel – Almost blooming right now, great shrub

Shrubs
Winterberry and Chokeberry – Red fruit in the fall, tolerant of wet feet

Virginia Sweetspire itea – Not happy dry; likes moisture to perform

Arrowwood Viburnum – Blue muffin doesn’t mature so large (5-6 feet); white flower in summer, blue fruit in fall, full shade to full sun, and it tolerates from wet to dry.

Perennials, grasses
Rush (juncus spp.) – Good seed heads, 12-36 inches in height and semi-emergent on the side of a pond.

Switchgrass (Panicum spp.) – Makes a monoculture stand in grass prairies. It’s 3 feet tall, and softer with a blonde color in the fall and likes wet feet. It is aggressive, so be careful.

Bulrush (Scirpus spp.) – grows 12-18 inches to 6-7 feet tall, woody stems in some cases, becoming more common in perennial nurseries

Sedge (Carex spp.) – Thrive in full shade; interesting color in a woodland environment

Perennials, flowers
Iris (Siberian and Flags) – Like an ornamental grass with a bloom in summertime; flag leaves can go 36 inches and be aggressive in wet environment

Daylily – How can you go wrong?

Liatris – Drier growing, but a magnificent plant that attracts wildlife.

Milkweed (asclepias) – Great butterfly attractor

Cardinal flower (lobelia) – Love wet feet, bright red color

Ferns (royal and cinnamon) – They can do rain gardens in the woods and work with the shade that you’ve got.

Plants not to use
Invasive species – Check with your state’s Department of Natural Resources for its noxious weed list. Also avoid plants with aggressive root systems (like willows).

Dry-loving plants (Taxus spp., sedum)