Water-Saving Tips from Jerusalem

I never realized how beautiful marigolds could be until I saw them growing in Jerusalem.
In that ancient city, all municipal plantings – which include lots of marigolds during the summer months – are watered by drip irrigation. In public gardens, as well as in parkways and highway medians, rows of brown tubing deliver water to the roots of each and every plant.
Drip irrigation was invented in Israel in 1956. Most of Israel’s freshwater supply comes from Lake Tiberias, also known as Lake Kinneret or the Sea of Galilee, which is located in the north of the country. Water travels from this lake through a national pipeline that reaches all the way to the Negev Desert in the south. Along the way, every drop of water must be used to its full potential.
Drip irrigation places water at the roots of a plant, where it is most needed. This eliminates the wasteful, errant spray we have come to accept as part of overhead or sprinkler irrigation.
For years, the major problem with drip irrigation has been clogged emitters. Emitters are devices which, snapped onto plastic tubing, drip water at a rate that is 50 to 100 times slower than the rate water is sprayed through conventional sprinklers. Put another way, a drip emitter will deliver in one hour the same amount of water delivered by a conventional sprinkler in one minute. But emitters are known for clogging and breaking, which means they require constant maintenance. If your drip emitter system is connected to an automatic timer, you might go away for several days during the summer thinking the watering of your plants is secure, only to return to find that, due to clogged emitters, some or your plants have died. Plastic tubing and snap-on emitters can be found at almost any nursery, garden supply, or hardware store.
Israel’s irrigation technologists have all but solved the problem of clogged emitters; the user no longer has to worry about snapping on emitters because they are already there. The latest drip irrigation tubing, which is about a half-inch in diameter, has no emitters visible to the eye. However, upon close inspection of the tubing, small holes at 12-inch intervals are revealed. There are no breaks in the tubing, yet, somehow, emitters have been hidden within the tubing during the manufacturing process. These seamless in-line emitters rarely clog, unless the water is high in salts or sediment, in which case a small filter is installed at the head of the line.
Aside from saving water, drip irrigation is the recommended way to apply water where the health of certain plants, such as marigolds, is concerned. Marigolds have no tolerance for wet flowers or leaves, and they readily develop fungus diseases where overhead sprinklers are used to water them. The drip-irrigated marigolds in Jerusalem, with their large pompon flowers of yellow and orange and their dark green, lacy leaves, appear to be as safe from fungus as any plants – excepting those made of wax – could possibly be.
Beat vinca fungus
Annual vinca (Catharanthus roseus) is another summer bedding plant the health of which is compromised by overhead irrigation. Many landscapers and professional gardeners have eliminated the pinwheel-flowered vinca from their list of summer annuals because of the fungus that commonly affects it. Often, within a few days of being planted, vinca shows signs of fungal wilt, which is rapidly followed by fungal death. In Jerusalem, the drip-irrigated vinca appears to be made of silk, so shiny are its leaves and so flawless its flowers.
With the introduction of several new cultivars, this is the right moment to renew our attempts to grow annual vinca. Its two well-known cultivars – one with mauve-violet flowers, and the other with white flowers that have red centers – now have red, pink and apricot flowered vincas for competition.
You can grow just about any kind of plant in Jerusalem, whether it requires winter cold or summer heat. Just 2 degrees closer to the equator than Los Angeles, its elevation is more than 2,000 feet. Due to this elevation, snow is not uncommon during the winter. Trees, such as apples, pears and almonds – which require a significant winter chill to produce crops – are frequently encountered. Yet in the summer, Jerusalem feels not just Mediterranean, but subtropical. This feeling is enhanced by the ubiquitous presence of bougainvillea, lantana and citrus trees.
Tip of the week: For some reason, the primary colors – red, yellow and blue – are seldom combined in the garden, but perhaps they should be. Recently, I saw red ivy geraniums, blue plumbago and yellow lantana growing together in a way that showed off each plant to good effect. In another garden, red and yellow cannas planted near blue agapanthus created a vivid splash of full-spectrum color.

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