dwarf crown of thorns (Euphorbia millii ‘Splendens’) in front of Marriott Hotel, Sherman Oaks

Question: I’m tired of reading books and articles on drought-tolerant plants featuring just spiny, cactusy plants. I want color and beauty. The idea of living without flowers and color is depressing. It is the jolt of a newly discovered blossom that gives one an adrenaline rush in the morning. Please write a book on this subject.
– Maria Munoz
La Crescenta
Answer: There is an enormous misconception about flowering plants and their water needs.
The main limiting factor to plant growth is cold. That’s why planting zones are determined by average coldest winter temperatures in each zone. Planting zones are not determined by annual rainfall.
Nearly all plants, properly sited and mulched, exhibit a marked degree of drought tolerance. Where gardening practices are consistent and enlightened, few perennial plants require more than two soakings per week, even in the hottest weather.
Let’s define soaking as saturating the soil in a plant’s root zone, whether with a hose or by drip irrigation. Mulch should be 2 inches deep between the trunk and the canopy perimeter line, sometimes referred to as the drip line since this is where water drips off a tree when it rains.
You should also fertilizer perennials at least once a year, in early February, with 2 pounds of actual nitrogen per 1,000 square feet and lesser amounts of phosphorus and potassium. Ideally, the ratio between these three elements should be 3-1-2 (nitrogen-phosphorus-potassium). Fertilization is best achieved by moving aside the mulch around the plant and sprinkling fertilizer over the soil surface. Strong, fertilized plants are best able to withstand dry weather conditions.
There are many drought-tolerant plants that show flowers (or colorful appendages known as bracts) throughout the year. Among these are bougainvillea, crown of thorns (Euphorbia millii), lavender and gazania.
Plants that grow from bulbs and associated underground storage organs (rhizomes, tubers and corms) are also drought tolerant to varying degrees.
Irises should be at the top of this list. Call them backyard orchids since no other plants, except orchids, can rival their voluptuous beauty. In fact, iris blooms have a silky softness that is lacking in many orchid species, whose flower texture is often waxy.
A special word of caution is in order concerning mulch. Where lavender, rosemary, California natives and many other drought-tolerant plants are concerned, the safest mulch is either gravel or decomposed granite. Organic mulches, such as the highly popular shredded cedar bark, hold water and, when used in conjunction with drought-tolerant species, must be kept a good 6 inches away from plant stems. When plant stems or tree trunks make contact with organic mulch, they can quickly rot.
Perhaps the best pictorial website for learning about the blooming possibilities encompassed by California natives is www.laspilitas.com. Among other features, there are pages on the site devoted to plants that bloom in each of the four seasons (February, May, August and November) so that, designing exclusively with leafy, non-cactusy natives, you can see flowers throughout the year and adhere to minimal water use.
But I would not close the door on succulent plants. For example, there is an extremely colorful, delightfully designed garden at Westholme Avenue and Santa Monica Boulevard in West Los Angeles. All of the plants are succulents but each was chosen for its colorful foliage, with the exception of a crown of thorns hedge, which sports scarlet bracts throughout the year. The result is an unrivaled cornucopia of blue, lavender, red, pink, yellow and orange.
There are also some recently planted, mostly water-thrifty specimens, with unusual shapes and textures, worth examining at a medical building on the north side of Roscoe Boulevard opposite Northridge Hospital Medical Center. An attractive mulch of small, flesh-colored stones has been used as a water-saving ground cover for the plants on display. There is a spectacular crossvine (Bignonia capreolata ‘Tangerine Beauty’) at the entrance that, thanks to its tendrils, has the capacity to climb more than 50 feet. It is a desirable selection for covering a tall chain link fence, trellised wall or gazebo.
Q: How and when should gardenias be thinned?
– Catherine Barabas
Granada Hills
A: Gardenias should be pruned sparingly, if at all, and only to remove asymmetrical growth outside the main body of the plant and to remove spindly growth from the inside. This should be done following completion of summer bloom, since gardenias begin producing next year’s flower buds in the fall.
Gardenias do not require pruning for their health. The goal in pruning them is to create a more symmetrical plant and to promote additional blooming on inside growth.
Q: I have lived in the same house (Reseda Boulevard, south of Rinaldi Street) for 29 years. Two years ago the rabbits came. Cute at first, they are eating me out of house and home. They loved the gazanias in the parkway and lots more. Any ideas?
– Steve Goldstein
Northridge
A: Although no plants deter rabbits, and hungry rabbits will eat virtually any vegetation, there is anecdotal evidence that rabbits may avoid some shrubs, perennials and vegetables.
The list includes yarrow, barberry, boxwood, silverberry (Elaeagnus), fuchsia, holly, roses, rosemary, viburnum, yucca, bear’s breech (Acanthus), daffodils, pampas grass (Cortaderia), euphorbia, sedum, geraniums, hellebore, irises, lupine, freeway daisies (Osteospermum), bamboo, celery, tomatoes, onions and parsnips.
The only sure way of keeping rabbits away is with a fence. It should be 3 feet above ground, going down 6 to 10 inches below ground, with a flange of a few inches bent outward at the bottom to thwart tunneling below. The mesh size should be no larger than 1 inch to prevent baby rabbits from squeezing through.
I would consider replacing your gazania with golden sedum (Sedum rupestre ‘Angelina’). This plant is as highly resistant to drought as any other ground cover and is reputedly unappetizing to rabbits. As it ages, golden sedum gradually changes color from yellow-green to deep gold.
Tip of the week
Encino Elementary School parents have done a beautiful job filling up planters throughout the school grounds that had been empty for years. What a pleasant, uplifting surprise for children and staff to see pansies, snapdragons, begonias and gardenias where nothing but dirt had been visible a short time ago. While visiting, I noticed a wonderful hedge along the school wall on Addison Street. The plant is known as long-leafed yellowwood (Podocarpus henkelii). It has charmingly droopy foliage and may be planted either as a hedge or, individually, as a specimen tree.