Blossom-End Rot: Tomatoes’ Rotten Trick
Question: For 12 years I’ve grown the best beefsteak tomatoes, but in the last few, the fruit has been coming with a flat side on the bottom that is a black crust. I cut off the crust and the rest is fine but they sure are ugly. What can I do to avoid this problem?
--J.S., Venice
Answer: Those leathery scars on the bottom of the fruit are called “blossom-end rot,” and are usually caused by sudden changes in soil moisture or a lack of calcium in the soil.
Switching between either extreme--from too much to too little moisture--can bring on this disease. For example, if you are watering regularly--say every week--and then stop for a few weeks, that sudden change will bring on blossom-end rot. Jim Waltrip, with vegetable seed grower Seminis Garden, says that when daily drip irrigation is used to maintain a consistent soil moisture, there are no troubles with end-rot.
Whether you use drip or not, try to keep the soil evenly moist. Mulch plants so they do not dry out too fast, but make sure the soil drains quickly and does not stay too soggy.
Waltrip also said that certain tomato varieties are more prone to end-rot, especially pear-shaped kinds.
Lack of calcium is the “textbook” cause, he said. Adding small amounts of calcium to the soil may help. Calcium is found in agricultural limestone and in ground oyster shell. One suggested cure is to add 5 pounds of pulverized limestone to each 100 square feet before planting. Carefully mix it into the top 10 inches of soil.
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Q: Three different roses have developed suckers, all of which are blooming with the same velvety-red, floribunda-type flower. Is this weird or are we missing something?
--B.A., Oak Park
A: As mysterious as this sounds, the answer is quite simple. A sucker is a strong sprout that arises from the roots of a plant. Many roses are grafted onto the roots of a different variety, most often a 100-year-old variety named ‘Dr. Huey.’ It is ‘Dr. Huey’ that has the velvety red blooms of medium size, so this growth must be coming from the roots, not the grafted or budded plant on top. You might also notice that the leaves on the suckers mildew easily, another characteristic of ‘Dr. Huey.’
Snap these suckers off with a quick jerk. If you cut suckers, they tend to return with a vengeance. Remove them as quickly as possible so they do not overwhelm the top growth--the variety you want to keep. It’s not uncommon to see roses in gardens that have been overwhelmed by the vigorous ‘Dr. Huey’ rootstock. When future sprouts arise, see whether they are coming from below the graft. Those coming from below the graft are suckers and should immediately be snapped off.
More and more roses are being grown on their own roots, which eliminates the problem of a separate rootstock.
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Q: We’re currently plagued by a white powder sort of mildew on the climbing roses. We’ve tried dozens of sprays and a fertilizer that’s supposed to protect them but it’s an endless struggle. Any suggestions?
--M.P., Los Angeles
A: This question is asked regularly, so the answer bears repeating. The kind of mildew you are describing is called powdery mildew. Some roses are more prone to mildew, and on those kinds it can be prevented--if you apply it before you see any signs of mildew--with the commonly available Funginex. Be sure to reapply it at the intervals suggested on the label. Fungi-Fighter (Bayleton) is another preventive useful on big climbers because it is systemic, so is taken up by the roots and distributed throughout the plant.
Fungicides like these won’t do much good once powdery mildew takes hold, but there are natural sulfur products that kill mildew on contact. These can be mixed with water and sprayed, or dusted directly on the plants. There is also a homemade baking soda spray that quickly knocks it down, though mildew may reappear and need to be sprayed again.
Don’t use the baking soda or the sulfur spray when temperatures exceed 75 or 80 degrees because they can burn leaves. After much experimenting, chemist and rose expert Tommy Cairns came up with the formula shown below.
Baking Soda Cure
To make a spray to cure powdery mildew, add the following to a cup of water:
1 1/2 tablespoons baking soda
1 tablespoon canola oil
1 tablespoon insecticidal soap
After all these ingredients have been added to the cup of water, add 1 tablespoon vinegar, then enough additional water to make 1 gallon of solution that can be sprayed on foliage.
If roses consistently mildew, you might try other varieties of roses, or other locations for the roses. It is said that breezeless locations with stagnant air often bring on mildew, so finding a breezy, sunny spot should help. There are also varieties that are touted as being more disease resistant.
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Q: How does one go about pruning a flowering maple without killing it?
--R.W., Los Angeles
A: According to Lew Whitney at Roger’s Gardens in Newport Beach, you can safely cut back an abutilon, or flowering maple, by evenly removing as much as two-thirds of the growth. Then clean out any spindly twigs that remain. A month or so after this harsh pruning--as new growth begins--do some light trimming to reshape the plant.
Ideally, it’s best to prune regularly--say about every two months--so plants don’t get too leggy. But most of us wait too long and then must whack them back, which means the plant won’t bloom for three to six months while it recovers.
Abutilons are almost always in flower, so there is no ideal time to prune, but early October or early March are probably the best times.
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Write to Robert Smaus, SoCal Living, Los Angeles Times, Times Mirror Square, Los Angeles, CA 90053; fax to (213) 237-4712; or e-mail robert.smaus@latimes.com.
