Category Archives: drought tolerant groundcovers

Plants that Hold up in the Heat

What happens to a plant when the thermometer tops 100 degrees like it did a couple weeks ago? Planning for more hot weather this summer is a requirement for a successful garden. Are there some plants that can survive tough times more easily?

Bees Bliss salvia

Photosynthesis is one of the most remarkable biochemical processes on earth and allows plants to use sunlight to make food from water and carbon dioxide. But at temperatures about 104 degrees the enzymes that carry out photosynthesis lose their shape and functionality. A garden that provides optimum light and water but gets too hot will be less vigorous. Tomatoes, for example, will drop blossoms and not set fruit if temperatures are over 90 degrees. Plants that endure hight heat can be stunted, weakened and attract pests and diseases even if water is available.

Plants do have natural systems that respond to heat problems. Some plants are better at this than others. Plants can cool themselves by pumping water out through the leaves for a kind of swamp cooler effect. They can also make “heat-shock” proteins which reduces problems from over heating. All these strategies do take resources away from a plants other needs like growth, flowering and fruiting.

It’s no surprise that many California natives are adapted to high temperatures. In my own garden I grow several plants that are doing quite well without irrigation and handled the heat wave just fine. One is Bees Bliss Sage, a low groundcover that can reach 6-8 ft wide draping over rocks and walls. It has an extended bloom time from mid-spring to early fall with whorls of lavender-blue flower spikes. Bees, butterflies and hummingbirds all find it attractive.

salvia clevelandii

Another plant that can handle high temps is salvia clevelandii. Right now it has just started its blooming cycle of electric blue-purple flowers. They will last through the summer. This salvia survives without any supplemental irrigation but if I give it an occasional deep watering and wash off the foliage every so often its much happier.

mimulus arantiacus

Who doesn’t like color in their garden? Mimulus or Sticky Monkey Flower blooms are showy and the hummingbirds love them. The Jelly Bean series has added bright pink colors in addition to white, orange, red and yellow but the traditional aurantiacus types are the most tolerant of drought.

As summer comes along the California fuchsia will provide the color in the garden. I like it that they spread by underground rhizomes and self sow. Free plants are always welcome. I have them planted on a slight slope where they tumble over a rock wall. My bees and hummingbirds find this plant irresistible.

penstemon heterophyllus

Other California native plants that can handle the heat with little water include eriogonum, manzanita, artemisia, California milkweed, ceanothus, mountain mahogany, bush poppy, bush lupine, native penstemon, monardella, mahonia nevinii , fremontodendron and holly-leafed cherry.

Other well adapted plants that are known to be more tolerant of heat include butterfly bush, germander, rosemary, smoke tree, rudbeckia, coreopsis, lantana, plumbago, gaillardia, lilac, sedums, oregano and verbena.

These plants can be the rock stars of your garden. Some natives can survive with no water after 2 years many look more attractive with a few deep waterings per summer. And don’t forget the organic soil amendments and wood chip mulch to encourage the soil microbes and keep the soil cool.

Kurapia – The Perfect Groundcover

A groundcover is defined as any plant that grows over an area of ground. They are usually low-growing, spreading plants that help stop weeds from growing and prevent moisture loss. We gardener know that they do so much more in the landscape. Living ground covers add beauty to the garden filling in between plants while holding the soil in place and preventing erosion. They contribute to soil health by encouraging microorganisms. A garden wouldn’t thrive as well without ground covers.

Kurapia_groundcover
Kurapia groundcover growing in part shade

With this in mind I encourage many kinds of ground covers in my landscape. It’s a difficult place to find the best ones because of the lack of winter sun and only 5 hours of good summer sun. Still I’ve found a choice one that I’d like to share. It’s tough and reliable in many situations including hot summer gardens. If it will grow in my yard it will surely grow in yours.

Kurapia is ta deep rooted, low water use, low maintenance ground cover. It’s parent is in the Lippia genus and has naturalized worldwide. However, Kurapia has been bred to have sterile seeds and its growth habit is much more compact and tamed. Though it is sterile with respect to seed production, it does flower and is bee and butterfly friendly, blooming from May to October. This is a good groundcover if pollination of nearby fruit trees is needed or your want to encourage bees in your garden for general pollination. If bees are an issue for someone in your family Kurapia can be mowed once or twice a month to cut the blooms off. Mowing benefits this groundcover making it grow denser which naturally surpasses weeds once it fills in.

Kurapia_closeup
Closeup of Kurapia flowers

Kurapia has been extensively studied at UC Davis and UC Riverside comparing it with No Mow as well as other drought tolerant cool and warm season grasses. Kurapia exceeded them all going 52 days without water and still maintained its green color. An extensive root system that goes as deep as four feet and a dense 2” to 3” tall mat-like top is the secret. The California sod grower recommends more frequent irrigation but it still requires just 60% of the water of a traditional lawn.

Kurapia does not require much fertilization either. One time in the spring for growth and flowering and once in the fall to keep the green color through the winter is sufficient. Mine looks great year round and I have to confess I’ve never fertilized it. Kurapia is evergreen and does not have a dormant period though growth stops or slows does in the winter. It spreads and self repairs by stolons. This groundcover grows in sun to partial shade requiring only three hours of sunlight. However it tends to stay more compact in full sun.

Kurapia will handle light to moderate foot traffic. It cannot take consistent high traffic though it is very walkable. My dog Sherman finds it great for his morning constitutional and I’ve never seen yellow spots as a traditional lawn will get.

Kurapia is hardy to 20 degrees though in tests it has survived temperatures as low as 12 degrees. It’s deep root system is unparalleled for erosion on slopes. Did I mention it takes 60% less water and how much you mow is up to you? Like I said, if it will grow in my garden under less than ideal conditions it will grow in yours.