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Waterwise Garden Design
by Helen Yoest - posted 06/08/18

The fountain in the author’s garden, “Helen’s Haven.” The fountain is refilled with rainwater collected from the roof. The bed surrounding the water feature is an oasis bed, receiving extra moisture from the splashing water as it spills from one tier to the next.

There was a time when I thought of water as a renewable resource. Deep down, I still want to believe this. Although our water supply is replenished (some years more than others), the distribution of water over my property varies. The gain doesn’t always equal the loss though – some years we take more than nature gives.

Since I come from an area that receives an average of 44 inches of rain a year, you may be surprised to hear me touting waterwise garden design. Out West, this is a way of life. However, on the East Coast, we have experienced long periods of drought in recent years. If Raleigh’s annual rainfall came as 1 inch every week, there would be little need for waterwise design. But it doesn’t. Summers, in particular, can be hot and dry. It wasn’t until we experienced the worst drought in 100 years, with outdoor watering restrictions and no major rain in sight, that I began to take note.

Being waterwise goes beyond plant choices and bed placement.

Think about other garden features as well. A major focal point in my front garden is a 6-foot-tall, three-tiered fountain. It is a fantastic feature – it makes a soothing sound, attracts wildlife and is beautiful to look at. I refill the water with harvested rainwater I capture in a 250-gallon converted food-storage container. These containers are easy to find, since they are intended for one-time use only. After they’ve been used, they either go to the landfill, or clever people find ways to repurpose them. They are great at capturing rain with only slight modifications. My “harvester” sits at the corner of my property, next to the house. The drain spout diverts rainwater into the harvester, with overflow going into an oasis bed. I have a hose hooked up at the bottom of the harvester. When the fountain needs refilling, all I need to do is turn the valve. If I don’t have water, I don’t turn on the fountain. It still provides water for the wildlife when it’s not running. When the fountain is running it’s a signal to all that we are rain rich, for the moment anyway.

Waterwise gardening is not new, but gardeners seem to have drifted away from the benefits and techniques of this design. This strategy is not limited only to gardening in periods of drought, but is a practical and effective way to garden anywhere, while at the same time practicing good environmental stewardship.

One of the major components of waterwise design is grouping plants with similar needs. This design principle has saved me countless hours of watering, plus the cost associated with that. But I soon realized a water-saving design also helped map my garden, thereby simplifying my plant choices.

In the past, before acquiring a plant I would only think of the plant’s sun requirements. If it needed extra water and I loved the plant, I didn’t pay much attention to where I’d plant it. I assumed I would be able to meet its needs. I rarely did, of course. Now when I select a plant, I not only look at its sun requirements, but its water needs as well. I know exactly where the plant will go, based on the map of my waterwise garden. Today, I’ll put a plant back on the shelf if I can’t meet its sun requirements and also find room in the appropriate bed. Although it was hard at first, looking back, I have no regrets. With so many great plants out there, I’ll just keep looking for those that work in my design.

Waterwise design doesn’t limit you to only drought-tolerant plants. It’s a planting scheme that uses all different kinds of plants, from agaves to tropicals, and places them based on their water requirements. The beds in a waterwise garden are divided into three zones: oasis, transitional and xeric.

An oasis zone is an area close to a water source. Sources can be drain spouts, rain barrels or a faucet and hose. The area around your front door is also considered an oasis zone, because you can easily water your container plants with water collected indoors.

Hosta thrive in the oasis bed next to the fountain.

Hardy Begonia edge a transitional zone bordering an oasis bed. It is watered every two weeks.

A transitional zone is an area about midway from the house to the property line. Plantings in this zone should be sustainable, requiring only occasional supplemental water. Typically, these are island beds, alongside driveways or raised beds.

This mixed border at Helen’s Haven is a transitional zone, receiving supplemental water only after six weeks without rain. Even then, only the thirstiest plants are watered with harvested rain.

A xeric zone is at the property’s perimeter. Plants in these zones should be tough and not require supplemental water.

Salvia, lavender (Lavandula spp.) and mugo pine (Pinus mugo) are happy in a xeric zone.

Helen Yoest’s rock garden is a xeric zone with lush plantings among the rocks.

It’s not difficult to be a waterwise gardener. Get a rain gauge to know exactly how much rainfall you receive. Only water when plants need it. Even the thirstiest plants, once established, only need approximately 1 inch of water a week. (However, container gardens may need daily watering in the heat of the summer.) Remember to mulch – its moisture-holding ability is one of your best defenses against drought!

Waterwise doesn’t mean that it can’t be lush. This is a transitional to xeric bed, receiving no supplemental water.

Cleome appear to be happy no matter which zone they’re in.

Tickseed (Coreopsis spp.) makes a great addition to transitional or xeric beds.

A version of this article appeared in Carolina Gardener Volume 26 Number 6.
Photography courtesy of Helen Yoest.


Helen Yoest is the author of Plants With Benefits: An Uninhibited Guide to the Aphrodisiac Herbs, Fruits, Flowers, & Veggies in Your Garden (2014, St. Lynn’s Press) and Gardening With Confidence – 50 Ways to Add Style for Personal Creativity (2012 GWC Press).