Irrigation Lessons from Jerusalem

I have just returned from three ethereal weeks in Jerusalem, which has two things in common with Los Angeles: arid, baking summer days and too many cars.
Whatever grows in Los Angeles, from roses to automobile traffic, seems to grow in Jerusalem as well.
The summer weather in Jerusalem, combined with water resources that are frequently in short supply, has restricted plant selection to dry climate species. Sprinklers are virtually absent from Jerusalem’s extensive municipal gardens, road medians and parkways. Drip irrigation is everywhere.
In ancient times, the people of Jerusalem were admonished not to plant orchards, since trees could become the subject of idol worship. Roses, with many species indigenous to the Middle East, were planted instead.
Today, roses provide much of the color in Jerusalem landscapes. Shrub and floribunda roses – the types that flower freely with minimal pruning – are used almost exclusively. Hybrid teas are virtually absent.
One of the most popular ornamental plants in Jerusalem is the red-leaf Japanese barberry (Berberis Thunbergil “Atropurpurea”). This architectonic shrub grows to 6 feet high and 3 feet wide and would make a strong statement in any garden. Its crimson leaves are held tightly to branches that point straight up to the sky. How appropriate that this species should be a signature plant of Jerusalem, a city made great by King David who, the Bible tells us, was of ruddy complexion.
The greatest treasure of Jerusalem’s public landscaped areas is the vast promenade that stretches down from the neighborhood of Talpiot. The promenade adheres to the side of a hill that slopes into a valley, the other side of which is the Old City – the original, walled city of Jerusalem.
A promenade is an area devoted to strolling. What an incredible urban resource! A promenade does honor to human beings. It is not like a public, recreational park; there are no ballfields or basketball courts or jogging paths. A promenade is meant for promenading or strolling, that slow, easy gait that allows people to converse or just enjoy each other’s company. A promenade gives people a feeling of dignity and connectedness to one another because there is not activity going on other than dialogue between human beings.
In a promenade, the landscaping has to be basic, in keeping with its human focus. If the landscaping were too ornate, a person would get lost looking at the plants and forget about the friend walking beside him. In the Jerusalem promenade, the landscape includes large blocks of Mediterranean plants which, even when in bloom, are comfortably unobtrusive; olive trees, rosemary and lavender are everywhere, planted in long rows through which black, polyethylene drip lines are woven.
Drip irrigation was invented in Israel 40 years ago. Its original applications were agricultural and each year, throughout the world, more and more acres of crops, especially fruit trees, are being watered by drip techniques. A drip emitter or mini-sprinkler (a drip derived device) uses less than 10 times the amount of water used by a conventional spray sprinkler.
In recent years, drip irrigation technology has been applied to ornamental landscapes and backyard gardens. The rap against drip has been its look – people don’t like the sight of black plastic tubing winding between their plants – and its maintenance; emitters and mini-sprinklers tend to clog. Use and constant cleaning of filters, together with regular draining of lines, is essential to the smooth running of a drip system.
Carole Stanzione of Valencia asks: “Can you please tell me how to get in touch with my county extension service … and, would this be the place to contact regarding some plants I have and do not know what they are?”
The Master Gardener Hot Line, which is sponsored by the Los Angeles County urban horticulture adviser, can be reached at (213) 744-4863. Your gardening questions will be answered free of charge through this service. To find out the names of plants in your garden, detach leaf or flower samples and take them to a local nursery for identification.
In the Santa Clarita area, your best bet is Green Thumb Nursery on San Fernando Road.
Gardening tip: In Jerusalem, annual vinca (Catharanthus roseus) is the most widely planted summer flower, and it shows no signs of the leaf phytophthora that kills thousands of vinca plants each summer in Los Angeles. The reason is not hard to find: in Jerusalem, vinca is drip irrigated, while here it gets overhead irrigation. To keep your vinca healthy, use drip emitters or carefully soak the soil with a slow trickle from a hose; getting vinca leaves damp is an open invitation to the lethal phytophthora fungus.

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