A shining example of a successfully planted slope

8-slopeYou can grow just about anything in our part of the world, and Helen Amritraj’s plantings on a quiet street in Calabasas provide a clear demonstration of this sublime horticultural truth.

Up and down her front slope, drought-tolerant aloes and barrel cactuses are flourishing, yet just above this same dry space, a water-needy hydrangea at the edge of her lawn flowers brilliantly. In her backyard, an artichoke plant thrives, while a nearby silver torch cactus in a patio pot produces an idiosyncratic trio of tubular blooms.

In describing her succulent slope, Amritraj wrote by email that it was “planted here 25 years ago” and that there were “lots of complaints from my neighbors.” But “now, 25 years later, some in my neighborhood are telling me how smart I was. It’s evolved over the years, but it is an interesting arrangement on a hard-to-plant small hill in front of the house.”

The blue fescue grass (Festuca glauca) growing at the base of her slope is a fitting complement to the plants above. Ornamental grasses require just a bit more water than succulents, and this blue fescue, situated at the bottom of her slope, benefits from the water that settles there.

Blue fescue is one of the most misunderstood plants around. It requires somewhat moist soil but will quickly rot except where soil is sandy or well-drained. Although touted for drought tolerance, it has a problem with all-day sun exposure unless, as at the base of Amritraj’s south facing slope, soil is adequately hydrated.

Amritraj has an artichoke in her backyard that is showing off several of its edible flower buds. They can be picked, boiled or steamed and then eaten, or they may be left on the plant for ornamental effect. When they open up, those edible buds become large flowers with soft mauve bristles, contrasting well with handsome, deeply-lobed artichoke foliage.

Amritraj has expansive bare, sun-soaked slopes on her property and she asked which plants I would recommend for covering them. Lantana was the first option to come to mind. Lantana blooms in yellow, orange, red, white, lavender and may even have several colors coexisting in the same flower, as is the case with the popular ‘Confetti’ variety, where pink, purple and yellow create a pleasing rainbow mix. Once established, lantana is demonstrably drought-tolerant and seems to be in bloom nearly all the time. I have seen trailing white and trailing lavender lantana effectively alternated for a tapestry effect, whether hugging slopes or hanging out of window boxes or from balcony planters.

‘Flower Carpet’ roses are also candidates for covering sunny slopes. They are available in scarlet, pink, coral, apple blossom, amber and yellow. Unlike most roses, ‘Flower Carpet’ blooms continuously, even without removal of faded blooms. Prune them back once a year to keep them at a desired height. Left unchecked, they will grow into thicket between three and four feet tall.

Here, a caveat is in order: extensive slopes that border undeveloped areas, once they are overtaken by ground cover, may become a haven for snakes. If you want to keep your slopes more accessible and user friendly, you will want to consider building terraces, upon whose flat terrain you can comfortably plant anything your heart desires, from fruit trees to herb gardens. Alternatively, you can dig holes into the side of the slope and plant trees, much like the Getty Center did when it planted hundreds of oaks, clearly visible from the 405 Freeway, on the slopes below.

As for slope irrigation, I would recommend installation of Netafim drip tubing, in order to minimize runoff. My second choice would be installation of the slowest moving rotary sprinklers — again, to minimize runoff — you can find.

Question: I’m not sure whether a small clump of calla lilies at the front of my home were unexpectedly prolific these past few months, or perhaps just normal if I were to give them lots of water every summer, as I did this past year. The first bloom opened during Christmas week, the last one just a couple of weeks ago.

I have lived at the same address since 1978 and these callas were there when I bought the house. But they have never put out more than a very few inflorescences each year. Last summer, I kept a near constant dripping of water near them to keep a large fern from turning brown as it usually does. I’m wondering whether the extra water was all the callas needed in order to produce more blooms in one winter than in all the previous 30-plus years combined.

They were absolutely constant. Whenever I cut back the blooms that were turning brown, more small ones were just developing. Most of the time there were eight to 12 fully opened blooms — and all winter and spring. The tallest stalks of the inflorescences were three feet, and I was surprised that the ones closest to the house were consistently the tallest, then medium-height in front of those, then the shortest in the very front — almost as if a florist had arranged them for a display. Guess I’ll try the constant watering again this summer and fall. Perhaps they will repeat their performance.

— Eldyn Karr, Newbury Park

Answer: Your letter is eloquent testimony to the importance of nurturing a plant throughout the year to maximize its flowering potential. Plants kept free from stress in the summer will flower more during their winter-spring bloom period. This is not only true of calla lilies but of nearly every other perennial plant. I once met an experienced gardener of California natives who told me that extra water and fertilizer application in winter months may significantly increase the flower production of these plants in the spring, even if they would survive just fine without the extra pampering.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.