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Gardening Q&A

May/June 2013 California Bountiful magazine



My yellow zucchini plant called Butterstick has unusual, tightly curled leaves on one of the bigger stems branching off the main plant. The zucchini is bumpy and deformed. The rest of this plant is normal, but this one branch is producing most of the zucchini. I checked the leaves for mites and other insects, but didn't see anything that could be causing it. Is it squash leaf curl? If so, will it affect the rest of the zucchini plants and garden crops?

Susan 

Dear Susan,

It sounds like squash leaf curl, which is a virus carried by whiteflies. They are sap-sucking insects, and have infected your squash plant. There is no cure, only prevention. Often the squash produced by the affected parts of the plant will be stunted or misshapen.

If only a part of the plant is affected, remove that part. Toss it in the garbage. You can harvest the squash from the rest of the plant.

After the season is over, toss the entire plant in the garbage, even if the rest of it does not show signs of the virus. Do not use it for compost.

You can hang sticky traps for whitefly. Also, remove all weeds growing around the vegetable garden so the whiteflies don't have a place to hide or overwinter.

You can call your local University of California Extension office (look under Farm Advisor in the county section of your phone directory) and talk to a Master Gardener.

Best of luck!

Pat

I live in Sri Lanka, and here the daytime temperature is about 85° F. It's a very sunny, dry climate. What are the most suitable flower bulbs to grow in my garden?

Salinda 

Dear Salinda,

I must say, I've never received a gardening question from Sri Lanka! It sounds like a beautiful place.

The problem with growing bulbs in a tropical setting is the weather. Most bulbs like a period of cold during their dormant season. That means they will likely bloom the first year you have them because they are growing and blooming on food stored in the bulb from the previous year. But production declines after that.

For example, here in California, tulips are practically impossible to keep going for more than a year or so without planting new bulbs because we just don't get enough cold weather.

From my research, I see that your climate is warm and dry, except during monsoon season, and without any cool weather. But I see that you can grow tea camellias. That said, I think there are some bulbs that might prosper for you.Some of the choices I am going to give you are actually corms or tubers, rather than true bulbs, but most people lump them all together.

If you can grow onions, chances are you can grow lilies (which are true bulbs). The Oriental lilies are fragrant, but usually come in shades of white or cream. The Asiatic varieties come in bright, vibrant colors, but aren't usually fragrant.

You might also try dahlias (a tuber like the potato). They love warm weather and come in many colors and sizes.

Other good possibilities: iris (a rhizome); crocosmia (a small, iris-like plant that will spread and makes brilliant orange flowers); watsonia (iris-like foliage with tall spikes of pink or white flowers);and amaryllis (spectacular flowers).

Also, paperwhite narcissus might work since they don't need a cooling period, but I'm not sure. They aren't an expensive plant, so it might not hurt to try.

I hope this helps. You might want to see what others you can find and try them. Sometimes plants will surprise you and do well even when the weather is against them!

Pat

I bought a home at a 3,400-foot elevation in Amador County. I have been blessed with a peach tree about 15 feet tall and a DBH (diameter at breast height) of 5 inches. Last summer, it produced about 50 wonderful peaches. I pruned it one-third back and now it's covered with golf-ball-sized fruit! I haven't seen any sign of peach leaf curl. Should I still spray the copper solution at the end of the year? Or am I safe?

You are too late to spray for curl this year, as you already know. The latest best time to spray (and the absolute best time to spray if you can spray only once) is at the pink bud stage—that is, when the flowers are showing color.

You would have leaf curl by now if you were going to get it. Keeping the old leaves cleaned up each year helps prevent the virus from spreading.

I find only the first flush of leaves gets the curl. A peach grower I once knew never sprayed, but picked off the affected leaves each year and disposed of them. The new leaves came out just fine.

If you want to spray next season, be sure to follow the directions as far as timing, but I used to spray only at pink bud and eventually quit spraying completely.

My suggestion is, the fewer chemicals, the better. Plus, it's one less task to do. Your task now is to thin the fruit. Pick away the smallest ones, then repeat.

My crepe myrtle and grapes have a powdery covering on the leaves. What is it and what can I do about it? Will it kill the plants?

It's powdery mildew, and my local nursery told me that in my area of the Northern California foothills, it is a dry-air mildew and that hosing off the leaves regularly would help.

It did: The parts of the plant where the sprinkler hit were free of the mildew. However, it is a fungal disease and can be controlled by a fungicide. You need to check at your local nursery and buy one that is designed for use on the plants that have the disease.

Sulphur is also used to control powdery mildew, and I have used that successfully, too. You can also use neem oil or jojoba oil, both of which are plant-based oils. Always follow label directions to the letter.

My impatiens are planted in the best location: plenty of filtered light, ample water, great soil and fed regularly. But all I get are leaves. What am I doing wrong?

I can tell you without asking any additional questions that the culprit is the fertilizer. Quit feeding them altogether or at least cut it back by two-thirds. The plants are getting too much good food and producing leaves instead of flowers. I guarantee this is the solution.

The winter squash plants have plenty of flowers, but I don't see any squash.

Squash, both summer and winter, first produce male flowers. Their job is to attract the bees that will be needed to move pollen from the male flowers to the female ones. Male flowers have a long stem. Female flowers have the baby squash at the base of the flower. If the flower gets pollinated, it will form a squash. So until the plant produces female flowers, you'll just have to wait.

See how Pat answered your questions earlier this year.

About Pat Rubin, California Bountiful's gardening expert


Pat Rubin

For Pat Rubin, gardening is more than just dirt and plants. "It's about history, romance, adventure and people," she says. "And it should be fun."

California Bountiful's gardening columnist has lived and chronicled this fun, hands-in-the-dirt approach for years—and for additional publications including Fine Gardening, Pacific Horticulture, Christian Science Monitor, Family Circle and The Sacramento Bee. Pat has also volunteered as a Master Gardener, speaks to garden clubs and appears regularly on gardening radio shows.

Need gardening advice? Ask the expert!

Send your questions to gardening@californiabountiful.com


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