http://www.pressdemocrat.com/article/20090221/WIRE/902211000/-1/TOPICS01?Title=Citrus-can-survive-even-in-a-drought

HOMEGROWN
Citrus can survive even in a drought

BY ROSEMAREY McCREARY
FOR THE PRESS DEMOCRAT
Published: Saturday, February 21, 2009 at 4:02 a.m.
Last Modified: Saturday, February 21, 2009 at 10:33 a.m.

When friends from the East Coast visited our home last summer, one of the highlights was watching them delight in picking Washington navel oranges from our tree and insisting that these were the best oranges they had ever, ever tasted. We doubt that the latter is true but agree that our tree does produce wonderful fruit.

Surprisingly, even people who have lived for years in the North Bay Wine Country are amazed that citrus can be so successful here. Our family has depended on our orange tree for more than two decades, ultimately taking for granted that, along with other citrus varieties, we have year-round fruit.

Last year was a bumper crop and we gave away bag after bag of oranges. Even today, as the new crop is ripening, we're still finding a few older strays that we hadn't noticed earlier. Meantime, there are plenty of Satsuma mandarins to keep us satisfied for several more weeks.

But these aren't the only citrus in our garden. Thankfully, the Meyer lemon tree is laden with yellow fruits since a young Eureka, along with a kumquat, hasn't yet come into production. And the Bearss lime is prolific.

If you're one of the many who have hesitated to plant citrus trees, here's some encouragement despite the water crunch we're facing this year.

Citrus of all types is beautifully suited to container culture, where less water is required for young plants than when they're put in the ground. As you might suspect, dwarf cultivars are best in containers and there are many to choose from at most nurseries. Container size determines dwarf height. Trees remain small in 12- to 16-inch pots, but in a 24-inch container, 5 to 10 feet is not uncommon.

Our 16-foot-tall Washington navel orange in the ground receives only occasional summer irrigation. It's planted in clay soil covered with thick mulch, but in sandy soil, it would require more frequent watering.

The Bearss lime, kumquat and Meyer lemon are planted in a wide area between the foundation and a concrete walkway set on several inches of gravel. The planting bed itself is clay soil amended with ample compost and covered with 4 inches of mulch. Summer irrigation here is minimal from a quarter-inch drip line circled around each plant, but roots very likely access moisture retained from winter rains in soil under the walkway.

Besides adequate moisture -- never soggy nor bone dry soil -- all citrus demand excellent drainage and air circulation. Give them space rather than squeezing them in with a group of companion plants where foliage is squished and roots face competition. Ample summer heat is needed, which makes for undependable success near the coast.

Provide nitrogen fertilizer according to package directions and periodic applications of micronutrients in a fully balanced product.

Looking ahead

There are a few practical considerations for existing citrus trees in the face of a dire water shortage this summer. If your tree is planted near a lawn, clear away all turf under the spread of the branches and a couple of feet beyond so there is no competition for available moisture. Maintain a 4-inch layer of organic mulch over the surface, keeping it about a foot away from the trunk.

Mulch helps to retain soil moisture even at lower depths. Citrus develops both deep and shallow roots and needs to have consistent moisture at lower levels, but it also tolerates 4-6 inches of dry soil at the surface between waterings.

Citrus are naturally low-branching trees, but if you want to reduce the canopy of your tree so there is less foliage to support or open it for visual effects, wait until May 1 when all danger of frost is past to cut out low or interior branches.

Winter worries

Prolonged deep drops in winter temperatures can damage citrus trees, but they do recover. All of our local microclimates are warm enough to sustain them, though it's always a good practice to waylay freezing air as much as possible.

Locating trees on a slope where cold air flows away is the first precaution.

Others are stringing the tree with a set of Christmas lights to raise the temperature a few degrees, spraying foliage with an antitranspirant such as Cloud Cover, and constructing a temporary frame to hold an insulating cover.

Rosemary McCreary, a Sonoma County gardener, gardening teacher and author, writes the weekly Homegrown column for The Press Democrat. Write to her at P.O. Box 910, Santa Rosa, 95402; or send fax to 521-5343.

CITRUS SURPRISES
Watch for suckers-- vigorous, non-fruiting sprouts from the rootstock -- that can easily overwhelm a small tree; remove them immediately. Suckers sprout low on the trunk below the graft line, usually a diagonal line a few inches up from the base.

Thorns appear on both suckers and on very young branches that sometimes grow rather erratically. Be sure to distinguish between the two so you don't sacrifice fruiting branches. Nip off annoying thorns.

Fruit on young trees may have thick skin, but eventually skin will be thinner.