Weekly Express-News Article

By Calvin R. Finch, PhD, SAWS Water Resources Director, and Horticulturist

Saturday, October 27, 2007

 “Citrus and Other Garden Tasks”

Many of us with citrus in our landscape or on the patio have fruit with black shallow holes on the surface of the fruit.  Meyer lemons and satsumas seem especially prone to the problem.  The blemish is caused by pecking by grackles and perhaps other birds.  Early in the fruits formation the damage could have been prevented by a fruit net, but now is too late.  The good news is that as ugly as the blemishes are, they do not seem to affect internal fruit quality.

Citrus leaves are very attractive in their own right, but some leaves in our gardens and on the patios are covered by a black mold.  It looks like soot, and is in fact, called sooty mold.  Sooty mold grows on “honeydew.”  Honeydew is the sugary excrement of sucking insects such as aphids or scale. This fall on citrus the “honeydew” producing insect is scale.  Scale are tiny insects that live under protective plates of calcium.  They grow on stems or under the leaves.  Scale is difficult to notice until the sooty mold shows up.

Scale is not a short-term threat to the citrus tree, but is a long-term problem.  Control it by thoroughly spraying the scale with horticultural oil.  Follow the label instructions closely.  The sooty mold will wear off the leaves after the “honeydew” production ends.

Another noticeable condition on citrus trees this autumn is damage by leaf miners on new growth at the end of the stems.  The leaves are deformed and distorted.  The first reaction is that the symptom looks like mildew damage.  On closer inspection the trails left by the insects within the leaf layers can be seen. 

As bad as the damage appears it will not cause long-term stress to the tree.  With fruit on the tree, and the insects within the leaves, or long gone, there is no spray that would be effective and allowed by its label.  Check the leaves, if the little green worm is still in the leaf, it can be squashed with pressure from your fingers.

For more information on citrus pests, visit plantanswers.com.

In addition to harvesting your citrus and dealing with problems on the citrus trees, there are other gardening tasks to consider this month. 

November is the month to plant trees and shrubs.  It is also a month where area nurseries have sales on items.  They only negative is that selection is not the greatest at this time of the year. 

Now is the time to plant pansies, cyclamen, and primula.  It is also not too late to plant snapdragons, calendula, dianthus, and stocks.  The cyclamen and primula require shade and everything else does better in full sun.

Divide iris, daylilies, Shasta daisies, and phlox in November.  Remember, when you replant the iris they must be planted so that the top of the rhizome is on the surface of the soil.  Individual clumps of Shasta daisies do not last long in our soil and weather conditions so it is necessary to create new plants every few years to insure you always have fresh growth.

 In the vegetable garden, plant spinach transplants this month.  Spinach grows very well in San Antonio winter gardens.  It is one of the most nutritious vegetables available.  There is still time to plant broccoli, cauliflower, Brussels sprouts, and other greens.  Also, plant beets, rutabagas, carrots, and turnips.

 It is not too late to fertilize your lawn for the winter.  Obtain a “winterizer” fertilizer with a 3-1-2 ratio of nutrients.  Common formulas are 15-5-10 or 16-8-12.  Despite the wet spring and summer it has been very dry this fall.  It is best if your lawn goes into the winter with a good irrigation every two or three weeks.