Struggling with a design for new landscape beds? There's no need to reinvent the wheel. Spikes and mounds — tall, wispy plants and short, dense plants — are a great way to fill up a large, sunny area.
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.
In short, many popular plants with big, wide green leaves such as magnolia tend to constantly be in trouble in the semi-arid climate of south-central Texas. That’s because leaves lose a lot of water through their surface area.
Look around any patch of Hill Country green 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, thin, with minimal surface area. Many are also pale in color, and waxy, fleshy, or fuzzy to the touch, features which help them retain water in hot weather.
To incorporate these bulletproof features into easy landscape design, lay them out in groups of spikes and mounds.
In design, “spikes” are plants with long, thin leaves: muhly grass, feathergrass, sotol, yucca, bulbine, and even society garlic. With long, thin leaves, they’re able to survive in a tough climate without losing so much water. They can be used as single specimens, or in sweeps to add instant architectural impact to any outdoor scene. Generally they’re some of the most ornamental of all xeriscape plants.
“Mounds,” on the other hand, are the plants with little fuzzy or waxy leaves (good for retaining water) and dense, sprawling shapes that shade their own roots: there are dozens of salvias to choose from, along with skullcaps, trailing rosemary and plumbago. Although short in stature, flowering mounds provide a big bang in terms of year-round color, and can fill up a lot of space in a hurry.
Remember, though, a common shortcoming in xeric design is using too many mounds: all those tiny little leaves can get a little monotonous without some contrast — especially the ones that turn brown in winter. To create instant texture, pair spikes and mounds with a few shrubs and trees.
And, finally, remember the rule of threes: when you’re laying out plants, use odd numbers – groups of three, five, and seven — and group similar plants to add pulse to a large area. Just remember to mulch in between.
If you’re looking for examples of spikes and mounds in action, you’ll see them everywhere in the commercial developments north of 1604, where new landscapes need to look marketable!