Sharon Hull, This Week in the Gaarden: Our Mediterranean climate great for citrus
Sentinel Staff Report
Article Launched: 05/14/2011 1:00:00 AM MDT
If you are a new gardener, or new to gardening in our Mediterranean climate, you will be pleased to learn we live in an excellent area for growing most citrus. Now that warmer, more settled weather has arrived, and with many months for a baby tree to get established before wintry temps reappear, this is the perfect time to plant a citrus tree.
What does citrus need to grow well and produce good fruit? Most need a winter with no frost or only occasional mild freezes. Lemons are the most cold-tolerant. They need well-drained soil on the acidic side, and in low fertility soils or in containers, regular fertilizer containing iron chelate. Though most citrus are fairly drought-tolerant once established, regular deep watering is recommended. They need all the sun they can get; citrus in part shade won't fruit well, if at all, and won't grow normally.
Some of our favorite citrus need high heat to achieve maximum flavor. If you garden near the coast, in Sunset Zone 17, you may have trouble growing good navel oranges or grapefruit because our summers are usually quite cool. There are plenty of citrus that do thrive here, however. You will probably be most satisfied in the Santa Cruz area with the flavor of most lemons, several mandarin oranges, Bearss limes, Trovita and Moro blood oranges. One navel orange, Skagg's Bonanza, tolerates our cool climate quite well, as does a hybrid grapefruit, Oro Blanco a cross between a grapefruit and a pomelo.
After selecting an appropriate site, dig a hole wider than the root ball. Since gophers love citrus roots, insert into the hole a gopher basket, leaving the top 2 to 3 inches of wire protruding above the soil line to discourage a gopher from getting into the root area inside the basket. Some authorities recommend adding organic matter to the soil to be back-filled around the root ball; others suggest that doing so creates an artificial zone that acts like a container, discouraging the tree's roots from growing into the surrounding soil. Especially if your soil is very sandy, I'd add the organic material. And I'd add some granular organic fertilizer at this time also; food such as Dr Earth or E.B. Stone won't burn tender new roots and will release nutrients gradually as the tree needs them. If the root ball has circling roots, loosen them up, then place the young tree into the gopher basket, making sure that the top of the root ball is set an inch or so above the original soil line. Since it will inevitably settle somewhat, this ensures you have not planted your tree too deeply. Then fill in around the root ball with the soil that was removed from the hole. At this time, create a raised soil collar larger than the root ball and surrounding it, to encourage irrigation water to stay in the area where it is needed. Water your new tree in thoroughly, and continue irrigating regularly during its first summer.
Like gophers, snails and to some extent slugs can do extensive damage to citrus, and planting time is the ideal time to prevent access to your small tree. They love to crawl up into the canopy, hide among the leaves and at night eat the tender new leaves, even the skin of the fruit, causing it to rot. They are extremely hard to find once they've reached the canopy so it is best to keep them out from the beginning.
A product that prevents snail access by being placed around the tree trunk is called Slug Shield. Made of woven copper wires, the Shield expands as the tree grows so it will not girdle it. According to the website, snails won't cross it because of the tangled abrasive nature of the metal itself, but also because it creates an electromagnetic field that repels the pests. Of course the shields prevent further infestation on older larger trees, too, though you'll need to find and remove all snails already lurking in the foliage. Look for Slug Shields in local garden centers or at www.slugshield.com.
Garden tips are provided courtesy of horticulturist Sharon Hull of the Pro-Build Garden Center. Contact her at 423-0223.