Cool Mountain

The Hill is Alive: Hardy ground cover plants such as blue daze, liriope and native Hawaiian varieties, akia and pohinahina do well in sunny, dry conditions. They also give this mountain pathway a rustic, wild feel.

This backyard landscape, located on approximately 6,000 square feet of hillside, had struggled under these tough conditions for a little more than 20 years. The homeowner used to enjoy walking along her backyard’s cinder path, which wove its way down a terraced hillside. But two decades of unrelenting sun and little rain had punished her 12 plumeria trees and all but obliterated her small collection of ground covers. She finally raised the white flag and called for help.

“When we first got here, we found a yard full of three- and four-foot-tall weeds,” says landscaper Kevin Mulkern, who was hired to rehabilitate the hillside. “We basically dug through the weeds, found whatever was underneath them and tried to bring them back.”

What Mulkern found were handfuls of mondo grass and blue daze, as well as a few remnants of mock orange bushes at the perimeter of the property. He replanted the ground cover plants in the shadier areas of the yard and added star jasmine bushes and green lariope. In areas that saw more sun, Mulkern installed hardy native plants, such as akia and pohinahina, both of which thrive in hot, rocky areas. To soften the hard lines of the foundation for the home’s elevated pool, he planted a pair of crepe gardenia plants. He placed another pair within the plumeria grove.

To rehabilitate the plumeria trees, Mulkern heavily pruned them, fertilized the soil and gave them plenty of water. He kept the existing irrigation lines, but replaced the sprinkler heads, which increased the range and volume of the watering.

The landscape’s cinder gravel path was also in pretty good shape, relatively free of weeds. Mulkern added a couple of inches of cinder to the path and replaced the plastic edging material that lined the trail.

“When we do a renovation like this, we often severely cut back trees, so that the plant material below has a chance to grow in,” says Mulkern.

“We want the plants to get maximum light and establish themselves before the canopy covers them up.”

When the trees did grow back several months later, their dense, green canopies provided screening from the neighbor’s property and abundant shade, which keeps the property about 10 degrees cooler than the surrounding area.

Today, the homeowner spends countless hours in her rustic yet hospitable yard, pulling the occasional weed, or picking up the few plumeria blossoms that fall onto the path or the mondo grass.

“She really enjoys fiddling around back here, primping, picking up things here or there,” says Mulkern. “Me, personally, I have a Zen approach to gardening, so I like the sight of some fallen leaves in the mondo. But it is just nice to be out here in the shade with a nice, cool breeze blowing through, so I can understand that.”

With temperature and humidity levels near record highs this summer, many homeowners are searching for ways to beat the heat. Air conditioners are great and the beach is never too far away, but how about your own backyard? There is nothing like the soft ruffle of leaves followed by a comforting trade wind to take the edge off a tough, humid day. With proper planning, a little hard work and a lot of patience, homeowners can build themselves backyard oases.

However, the optimal word is patience, especially if you are working on a mountainside landscape such as Mulkern did. If you don’t have larger canopy trees on your property already, they are expensive to purchase and can be difficult to transport and plant. Steve Dewald, of Steve’s Gardening Service, suggests that homeowners make a five-year plan, installing smaller trees and slowly phasing in shade-tolerant plants later.

The Big Blue: The flambego bush has a beautiful blue flower but it is a little unruly. Landscaper Kevin Mulkern combined the plant with a mock orange hedge, creating a fuller more orderly bush.

“The average couple with a new house will have spent all their money on their house, so they aren’t going to have anything left to spend on a field-stock plumeria tree,” says Dewald. “Patience is a virtue, because patience will save you money.”

According to Dewald, this is especially the case if you live in a harsh environment, like on a mountainside, where plant material grows slowly. He also suggests that homeowners look carefully at what is growing in their current landscape, before they start excavating and cutting down existing trees and shrubbery. “Sometimes people don’t realize the value of their plant material,” says Dewald. “That 30-foot plumeria tree in your backyard may be making a mess, but you just can’t buy one that big anywhere, so you should really think about keeping it around.”

Gary Shinn, of Hokuahi Lawns, agrees. The landscaper says that homeowners should pay attention to the plants growing in their yards and other properties in their neighborhood. That observation could save a lot of time and money.

“If you’re building a landscape on a rocky slope or in another inhospitable environment, you should be aware that your trees aren’t going to grow to the full potential,” says Shinn. “They might reach half or even a third of their expected heights, so look around, see what thrives and plan accordingly.”

For those who want to brave the elements and plant a shade tree in a hot, rocky environment, Shinn recommends Formosan koa, red coral and portocarpus. If you’re dead set on a plumeria tree, he recommends the Singapore variety, which is the hardiest of the trees.

Trail Mix: The property's cinder path, which weaves up and down the mountain side, is producted by a small grove of plumeria trees. As a result the landscape is approximately 10 degrees cooler than the surounding area.

Shinn also reminds homeowners that the irrigation needs of a rocky, dry landscape are different from those of a yard on a flat piece of property. To guard against erosion, mountainside landscapes need to be irrigated more frequently, for shorter durations. When the landscape is first getting established, it should be watered as many as five to six times a day. After everything is grown in, homeowners can get by with three or fewer waterings a day.

If the thought of using that much water gives you pause, you might consider a drip irrigation system, which, as its name suggests, slowly and efficiently puts water exactly where it is needed. Normally, Richard Long, of Reliable Landscaping & Sprinklers, avoids the complicated and sometimes finicky systems. But under the right conditions, they are a cost-effective solution: “A lot of times, conventional sprinkler systems will spread the water far and wide, much farther and wider than you want,” says Long. “You end up irrigating areas that you didn’t intend to and suddenly you have a weed problem. Drip irrigation puts the water right where you need it, without the threat of erosion.”

Long also suggests another way to avoid complicated irrigation issues: Install plants that need very little water in the first place. Cactuses, succulents and many Native Hawaiian coastal plants thrive in arid climates. He recommends the firecracker plant, which features explosive blossoms and a full body that can cascade down a hillside. “Citrus trees do well, too,” says Long. “They come in three different sizes—dwarf, semi-dwarf and standard—so you can choose whatever size fits your yard. Depending on its size, it can provide plenty of shade and, of course, delicious fruit, which is always nice.”