Start grooming plants, vegetables for fair contests

The Clark County Fair & Rodeo will be taking place in Logandale April 8-11. Start grooming your plants and garden vegetables to enter for judging in the horticulture division on April 8. You can enter your vegetables, fruit, container plants, cut flowers or artistic floral arrangements. Go to www.ccfair.com and click on exhibits/horticulture for classifications and rules.

Entries may be delivered to the fairgrounds in Logandale on April 8 or to the University of Nevada Cooperative Extension office in Las Vegas on April 7.

Call the Cooperative Extension at 257-5556 for more information about entry drop-offs in Las Vegas .

Q: I started reading your column in our paper recently and found that you give advice on trees also. I have several Carolina cherry trees that were really nice and full of leaves when I bought them in 2007. Over time, they have been losing their leaves and seem quite bare. Now, about one-third of the tops are either dying or dead. When I broke a tree down to the bottom (good) half, I found a triangle-shaped, whitish worm coming out from the trunk and that tree finally died. Are these trees treatable or should I just write them off?

A: This is most likely due to the flatheaded apple tree borer, which is similar to the description you gave. I will send you a picture so you can identify it for sure. The attacked trees have been weakened from sunburn on the trunk or major limbs. This can happen when they begin to lose their canopy and lose shade on the trunk.

These are relatively thin-barked trees and easily damaged by strong sunlight when they are young. They are also not an easy tree to grow here. They will really suffer if they are planted in a location where they receive late afternoon sun or that has a southern exposure and really suffer if they are planted in rock mulch. They will do much better if they are on the east or northeast side of a home. They also will do better with organic mulches rather than rock mulches.

As they get larger, they need more water. So if they are on drip irrigation, it is really important that more emitters be added to the tree as it gets larger. They need the soil improved when they are planted so it is critical to use compost in the planting hole at the time of planting.

It just depends on how much damage these insects did. I would take a sharp, sterile knife and start excising these insects as well as removing all wood damaged from their activity. Let the tree heal normally after you clean out the damage. If the damage extends more than half way around the trunk, remove the tree and start over. If the extensive damage is in a major limb, remove the limb. Otherwise let it heal.

On fruit trees we paint the potentially damaged areas with diluted white latex paint. I think this would look dumb on Carolina cherry though.

Q: Your article states that heavy waterings are good for fig trees. Please give me an idea of how long to run the hose at the base of my fig tree.

A: I have no idea how long to run your hose in terms of minutes or hours. That is like asking how many minutes of coffee or tea you would like to be served.

I will tell you that a large fig tree may take anywhere from 30 to 40 gallons at each watering, possibly more if it is really big. Equally important is how often to water a fig tree. As they are producing fruit, it is important to water them fairly often.

Right now we are watering figs once a week at the University of Nevada Cooperative Extension Master Gardener Orchard in North Las Vegas. Starting May 1, or earlier if it gets hotter, we will water them twice a week. At the hottest part of the summer we water them three times a week.

We also have wood mulch, 3-6 inches deep, around the trees. This helps conserve water and stretch our watering intervals. We have free wood mulch at the orchard.

Without a mulch you may have to water more often, especially if you start to drop fruit. Figs will drop if the soil gets too dry and if you do not water deeply.

Q: We’ve probably all seen the cherry blossoms on the trees around Las Vegas for the past couple of weeks. What type of cherry trees are these as the fruit is very sour?

A: This is probably not cherry but flowering plum. They produce small numbers of small, sour plums and are valued primarily for their ornamental appeal of spring flowers and summer, purple foliage.

Q: I have a 45-to-50-year-old mulberry tree. It has a hole in the trunk, about the size of a small cell phone. It does have some sap coming out and I try to hose it out every few weeks. When I do, sap and small pieces of wood come out. How do I fix this?

A: Just leave the tree alone. If it is growing well, it will heal itself. Sap coming out is usually not a problem. It could be for a variety of reasons but if you are not seeing any other types of damage or dieback then leave it alone.

Q: Based upon your recommendations for spraying a nectarine tree to prevent fruit scarring, I bought a ferti-lome product containing spinosad in the ingredients. Do I spray when the blooms are present or should I be waiting until the leaves are pretty evident? I don’t want to interrupt pollination.

A: As a general rule, do not spray anything in bloom with a pesticide. Period. Wait until the petals have fallen, then you can start your spray program.

Bob Morris is an associate professor with the University of Nevada Cooperative Extension. Direct gardening questions to the master gardener hot line at 257-5555 or contact Morris by e-mail at morrisr@unce.unr.edu.