Spikes and Mounds

If you’re removing turfgrass, struggling with a design for new landscape beds, and fed up with worrying about plant selection, there’s no need to reinvent the wheel. To fill up a big area in a hurry — especially in the sun — remember spikes and mounds. Once you learn this concept, you’ll realize it’s quite common in successful southwestern landscape design.

Look around any patch of Texas greenery and you’ll see a pattern. Leaves that can resist drying sun and wind — the ones you don’t worry about watering every August — tend to be tiny or thin, with minimal surface area. Many drought-tolerant leaves are also waxy, fleshy, or fuzzy to the touch — due to coatings and hairlike features that help them retain water in hot weather.

In contrast, landscape plants with big, wide leaves (like magnolia and caladium) tend to suffer in summer, because their leaves lose a lot of water through their surface area.

So to incorporate bulletproof design features your landscape, just lay plants out in groups of spikes and mounds.

In design speak, “spikes” are plants with long, thin leaves: these include bunchgrasses, sotols, yuccas, nolinas, and many others. With long, thin leaves, they’re able to endure a tough climate without losing so much water. Use them as single specimens or in sweeps to add instant architectural impact to any outdoor scene. Generally “spikes” are some of the most ornamental of all desert plants.

“Mounds,” on the other hand, tend to be the plants with fuzzy or waxy little leaves and a sage-like, sprawling and low growing form. Think rosemary, sage, dalea, lantana and many of the other flowering watersaver plants. Just remember, a common shortcoming in xeric design is using too many mounds. All those tiny little leaves can get pretty monotonous without some contrast — especially if they’re not evergreen. To avoid a sea of brown little leaves in winter, group the mounds with spikes, shrubs and trees to create texture and shade.

Remember the rule of threes: when you’re laying out plants, use odd numbers and lay out similar plants in groups to provide instant texture for a large area. You can even leave spaces in between, as long as you remember to mulch them against weeds.

If you’re looking for examples of spikes and mounds in action, you’ll see them everywhere in the brand new commercial developments north of 1604, where landscapes need to look marketable!

Picture of Brad Wier
Brad Wier
Brad Wier is a SAWS conservation planner. Years in South Texas landscaping and public horticulture gave him a lasting enthusiasm for native plants that don’t die when sprinklers -- and gardeners -- break down. He’d rather save time and water for kayaking and tubing. He is a former kilt model, and hears hummingbirds.
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