Valley climate not best for nectarines

: We live in Sun City Summerlin and have a dwarf nectarine tree which was planted about 10 years ago. Each year the fruit is badly blemished so we let the birds have a field day. This year, we decided to cover it with a net so there would be some to harvest. They also were badly blemished but nevertheless very sweet tasting. The blemishes are brown, veinlike, thick-skinned blemishes. Is there something we can do to prevent this in the future?

A: Nectarine quality of fruit is very variable in this climate. Some varieties do much better than others as far as the quality of taste.

The damage to the fruit is due to Western flower thrips. My fruit newsletter addresses this problem; anyone can get it by requesting it by e-mail, morrisr@unce.unr.edu, or calling the University of Nevada Cooperative Extension master gardener's help line at 257-5555.

We use Spinosad (you have to consult the ingredients on the label but I think you can find it at local nurseries). Follow label directions and begin spraying shortly after bloom. You will need multiple applications and use a spreader sticker in the spray mix.

Q: I am writing/asking this for my mother. Her lemon and lime trees leaves are turned yellow-brown this past winter. Is this just because of winter or is this something serious? Also why are the rind colors on the fruit different? The lime rind is yellow like a lemon and the lemon rinds are like oranges? Is this the climate?

A: Citrus leaves will turn yellow in the winter if the temperatures are low enough. This is cold damage and should not affect the plant otherwise.

Are you sure the plants weren't mixed up at the nursery? It is really hard to make a judgment without knowing which trees they are. Limes will turn yellow when they mature (if it is a Mexican aka Key lime), but I have never heard of a lemon turning orange.

The other possibility is that the rootstock survived (which could be a sour orange or mandarin) and not the lemon. Lemons are frequently budded or grafted onto an orange rootstock. If the top dies (lemon) what survives and grows is the orange rootstock. The death could have been in the nursery or in your yard.

Q: I need to know what month is the best to skin a Mexican fan palm and how do you skin it? I have gone everywhere to find a book on the subject and can't.

A: I would wait until early spring, like right about now. You would need a sharp linoleum knife and cut off the base of the palm frond at the point where the frond is attached to the trunk. I think a few attempts at cutting them off and you will discover where this is.

Keep the knife sharp.

Q: We have mostly desert landscape with an area of fescue lawn. We also have dogs and they prefer peeing in the lawn area, which results in brown spots that need to be reseeded. What can you tell me about zoysiagrass in Las Vegas? The ads say I can put plugs in my fescue lawn, and they will spread and give me a lawn that requires less water, less mowing and a tolerance for dog urine. Are the ads believable or are they hype?

A: Be careful of the ads about zoysiagrass. There is some truth to them but the type seen available by mail order are not the best for here. Zoysia grows slowly and so establishes slowly. It has some good salt tolerance (like in urine) but so does bermudagrass.

There is one particular variety that I would recommend if you are set on getting zoysia. The variety is called El Toro, which was developed in California and does have some distinct advantages over some other zoysia types.

All grasses have their pluses and minuses. There is no perfect grass. Zoysia is planted as plugs or sod and it is planted when it starts to warm up until about mid-July. It is fairly slow to establish compared to other grasses, which is part of the appeal, since less mowing is needed. In some cases it can take two years to establish from plugs.

Zoysiagrasses are tough and take a lot of abuse. You cannot overseed it like you can hybrid bermudagrass for winter green color. It will be brown during the winter. Water use is about the same as bermudagrass.

With fescue you can spray it with Roundup about a week before you plant zoysia plugs and then you can plant directly into the dying lawn. It will look ragged for awhile. Water and fertilize it frequently to get it to fill in more rapidly. It has very few pest problems.

Q: I have a mesquite tree that is dropping its leaves. Not being from this area and never having had a mesquite tree before, I don't know if this is normal or not. I think it is getting enough water.

A: Mesquite is only evergreen if the winter temperature stays warm. With too much cold they become deciduous and drop their leaves. It's nothing to worry about.

Look at how much new growth you are getting from the tree. That is a clue to whether it is getting enough, too much or too little water. Too much water and mesquites will grow extremely rapidly with a very dense canopy. With not enough water, it will grow very slowly and have an open canopy.

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.