Gravel Gardens Explained

If you want to start a garden, but you don’t have time to tend to one, turn to a system that’s been growing in popularity for its eco-friendly and low maintenance reputation: gravel gardens. It’s a form of xeric gardening—planting with water conservation in mind—that uses small pebbles in place of soil amendments and mulch.

What Is a Gravel Garden?

As the name implies, a gravel garden is an area of land where mostly native plants grow in a bordered section of gravel. A sustainable alternative to some other gardening systems, gravel gardens require about 80% less maintenance than a typical perennial garden. “When we create these, we want to create a garden that will be good on its own.  Basically, without the input of additional water, fertilizer, and other chemicals that you would use to protect your plants,” says Jeff Epping, director of horticulture at Olbrich Botanical Gardens.

Their ability to flourish with very little water and zero soil amendments also means you don’t need to worry about weed growth. “A lot of weeds that we experience thrive in very rich, moist soils,” Epping says. The dry environment of a gravel garden means weed seeds don’t have what they need to germinate, grow, and thrive.

While it may seem like you need a green thumb to be able to grow plant matter in rocks, even beginners can start a gravel garden. Best of all, the environment you’ll create is highly attractive for perennials, bulbs, grasses, and other types of native plants.

How to Create a Gravel Garden

Anyone can create a gravel garden.  However, they’re especially ideal for people who have a hard time keeping plants alive due to harsh growing conditions.  Conditions like dry soil and full sun. And of course, they’re perfect for anyone looking for a relatively hands-off approach to gardening.

Does this sound like the right fit for you and your home? If so, we recommend starting your gravel garden in the spring, which is the best time to plant and establish greenery. “Start out small and see how it goes for you if you don’t want to jump in full force,” Epping says.

Find the Right Location

Like many gardening projects, you’ll need to be thoughtful about where you place your gravel garden. It can be as simple as a small plot of land in your backyard—or you can make one that takes over your entire landscape. “They’re great for areas that may already be experiencing conditions that make them hot and dry,” says Josh Williams.  He is garden manager at Paul J. Ciener Botanical Garden. He says an area that receives full sun is ideal.

The soil

Also consider the type of soil you’re working with—soils that are harder to grow in (think too rocky or harder clay) would work well for a gravel garden. No matter your dirt’s composition, a successful gravel garden should always have well-drained soil.

The drainage

Select a sunny, open site with decent drainage—an area along a driveway, sidewalk, south side of a home, or front curb is ideal. Remove any existing lawn or plantings, making sure to get rid of tenacious weeds with extensive root systems that may come back to haunt you later. This is typically done with a sod cutter, by smothering with cardboard or plastic, or with a nonselective herbicide. Existing drought-tolerant shrubs can be left and designed into the garden.

Outline the space and note key measurements. Start a wish list of plants including both grasses and perennials. Consider the plant height and strive for a palette that offers a succession of blooms. Next, determine the square footage—then use an online gravel and plant calculator to do the math of what you need to buy.

Install an Edge and Spread the Gravel

Enclose the space with a solid border or hard edge. Medium stones, large boulders, or stacked pavers work well. Also, a foundation of a building, a driveway, an existing sidewalk works well.  Just be sure there’s a rim tall enough to retain a 5-inch layer of gravel. If gravel tapers off at the edges of your garden, weeds will easily find their way into the soil below and germinate.

The choice of gravel matters a lot. Picture marbles in a jar—pieces of stone that are all relatively the same size and shape and retain some movement and air space between them. Pea gravel or washed ¼- to ⅜-inch quartzite or granite-chip gravel are good choices. Avoid larger gravel; organic matter will build up in the openings between stones, inviting weeds. Before pouring in the gravel, drive in stakes every 3 to 5 feet and mark them at 5 inches, to ensure a consistent gravel layer. Too deep, and the plants perform poorly. Too shallow and weed seedlings will take hold in the soil below.

Place Your Plants and Develop an Irrigation Plan

Select drought-tolerant, deep-rooting species in 3½- to 4½-inch pots.  Their 4-inch root balls are the perfect size to be gently molded to match the depth of the gravel layer. Space plants 12 to 16 inches apart. Loosen tight roots if needed, and peel off the top ½ to 1 inch of soil mix to rid yourself of dormant weed seeds. (Put this excess potting soil in a bucket—never mix it in with the gravel.) Dig a hole in the gravel, taking care not to stir up the soil below. Insert the plant, making sure the crown is even with or just below the surface of the gravel. You will have a sea of gravel with dots of green, but don’t despair. In a couple of years, you (and wildlife) will enjoy a diverse tapestry of lush, colorful plants, and the gravel will lie hidden below, doing its job of controlling your weeds.

The key to a good start is water, water, and more water. This seems contrary to the whole gravel garden concept, but the water requirement changes as the plants root into the soil below the gravel. This may mean daily watering on sunny, hot, windy days the first two years. The best way to know when it’s time to water is by monitoring the plants each morning. Consider rigging up a temporary irrigation system the first season with hoses and impact sprinklers.

Spring cleaning

For both aesthetic and horticultural reasons, it’s imperative to do a thorough spring cleaning. Each March, cut back and remove all spent plant material before it has a chance to decompose. Organic debris trapped in the gravel creates nutrient-rich pockets where weed seeds readily germinate. Finish by blowing the gravel surface clean to remove lingering debris and keep the gravel free of organic matter.

Great Plants for a Gravel Garden

Many different types of plants can grow in a gravel garden, including bulbs, perennials, and grasses. Since gravel gardens are meant to thrive with little water, look for plants that are drought tolerant. Also choose varieties that have deep root systems, which can pull moisture from all levels of the soil.

When in doubt, opt for native plants, which are often drought tolerant and attract pollinators, like bees and butterflies. “The best plants for gravel gardens often are our very own native prairie plants because they are very drought tolerant by nature and have deep root systems,” Epping affirms.

Prairie Dropseed (Sporobolus heterolepis)

Little Bluestem (Schizachyrium Scoparium)

Purple Sensation (Allium Hollandicum)

Autumn Joy (Sedum Herbstfreude)

Pale Purple Coneflower (Echinacea Pallida)

Black-Eyed Susan (Rudbeckia Hirta)

English Lavender (Lavandula Angustifolia)

October Skies (Aster Oblongifolium)

Eastern Beebalm (Monarda Bradburiana)

February Gold (Cyclamineus Daffodil)

Gravel Garden Care

While the overarching goal of a gravel garden is to make it relatively low maintenance, extra nurturing is required when you’re starting out to help plants get established. After that, some simple annual care is all you’ll need to provide.

If you embark on a gravel garden, know that the biggest investment and hardest work happen in the first two years, when more watering is required. But after that, your landscape largely takes care of itself.

Source:  midwestliving.com; marthastewart.com

Photo credit:  Jeff Epping

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