Protect tender plants during winter freezes

Saturday I will demonstrate how to prune a peach and nectarine tree at the University of Nevada Cooperative Extension Master Gardener Orchard in North Las Vegas. Miniature peach and nectarine also will be demonstrated.

Demonstrations will begin at 9 a.m., and start again at 10 and 11 a.m. The orchard is located just north of the Aliante development in North Las Vegas, 100 yards east of the North Decatur Boulevard and Horse Drive intersection.

Once participants learn pruning methods, it is hoped they will help prune at least one tree under the mentorship of the orchard volunteers.

Also, if you bring your hand shears and loppers, we will show you how to sharpen and adjust them.

Advanced registration is not necessary, but orchard volunteers are asking for a $5 donation to help defray some of the costs for educational programming. If this is a hardship for anyone, please let me know at extremehort@aol.com

For specific directions, call the master gardener help line at 702-257-5555 before Saturday morning; otherwise call the orchard at 702-257-5532 on Saturday morning.

With this cold weather coming in, it is best to watch the weather forecasts closely for alerts to freezing temperatures. Wind, in combination with low temperatures, is more damaging than just low temperatures alone. Put a light sheet over the tomatoes and other tender vegetables before it gets cold. Pull containers inside a protected area or next to a west-facing wall that stays warm during the night.

Before you go to bed, look at the sky. If it is cloudless, then the chance for freezing temperatures is increased. When it is cloudy, there is less likely a chance of frost.

Q: For starters, I am a huge supporter of your work; I am very passionate about desert gardening so thank you for what you do. I will soon be moving to another part of the Mojave Desert in Kern County, Calif., where I intend to grow all my own food and be completely self-sufficient. My only goal is food production so what are the most important things to remember when maintaining fruit and nut trees in the desert.

A: You asked me about maintenance so I will not include site selection, plant selection and planting, which can be a huge mistake if these are not considered.

My top things to remember would be adequate and timely irrigations, adequate and appropriate fertilizer applications, renewing organic mulch regularly, protection from varmints, appropriate pruning and thinning, and insect and disease control when necessary.

Keep an eye on my blog because I will soon post a calendar of operations for fruit trees: what to do and when. I am also posting videos on YouTube, under the name of Extremehort, showing you how to do these things. Eventually they will be linked to the blog and vice versa.

Since you don't seem to be interested in marketing what you produce, I did not include appropriate storage techniques to extend your harvest and post-harvest handling.

Q: I noticed this morning two spots on my mesquite tree where there was a crystalized substance emanating from two different locations on the same trunk. I knocked off the substance to see if I could detect insects and found a small white worm. Also the tree trunk where the substance is located has a slit/crack in the bark. Please advise. Thank you.

A: The pictures you sent indicate sunburn damage and sap oozing from the sunburned area. When mesquite grows naturally, it is more shrubby and has lots of foliage covering its branches. When we prune them to be more like landscape trees and expose these branches to lots of direct sunlight we can get damage from our high-intensity sunlight.

In the future it might be best to leave some of the branches to shade young stems and the trunk until it develops the bark and furrowing of older age. At that point, those parts of the trees are more resistant to potential damage from direct sunlight.

If you notice in the picture, this damage appears to be on the upper surfaces that are more exposed to direct sunlight.

I think they will recover. If you get any new growth that might shade these branches more, please allow them to grow until the tree and those parts of the tree get a bit older.

Q: I am thinking of skinning my Mexican fan palm up a bit more on the trunk. Will that expose the trunk to more possible damage? The second palm I want to do the same thing to, but I don't know what kind of palm it is. They are all 15 years old.

A: There are two types of pruning on palms done here that affect the appearance of the trunk. One is to leave a part of the frond on the trunk of the tree. This gives the trunk a rough, informal or wilder appearance.

The other method is sometimes called skinning. It focuses on removing the part of the frond that remains on the trunk all the way back to the trunk. It gives the palm a smooth, more formal appearance and is frequently done to palms where people congregate.

Usually skinning is done with a sharp knife like a linoleum knife. It dulls quickly when you do this so you must sharpen the knife frequently. The knife cuts the base of the frond very close to the trunk leaving a smooth trunk and no noticeable frond remnant.

There are arguments both for and against skinning a palm. I personally don't see a problem with skinning palms provided you don't cut too deeply into the trunk.

You can skin back any of the fronds that have died totally to the trunk. If you remove any palm fronds that were still green, then I would wait until the remaining part of the frond dies back to the trunk.

Q: I would like to cut back some acacia, Texas ranger and rosemary plants that have grown too large. When is the best time to do so?

A: The basic rule of thumb is that for plants that you are not appreciating for their summer flowers, prune them back during the winter months after leaf drop. If it is very light pruning, then you can do that any time.

On those plants that you appreciate for their spring flowers, prune them as soon as their bloom time is over regardless of the time of year. If the plants bloom on last year's wood (usually very early in the spring), then the time of year for pruning is late spring or early summer just after flowering. This will give them time to grow new growth for next year's spring blooms.

If they bloom during the summer months, this would be on the current season's growth, then prune them in the late fall or winter.

If acacia is not grown for its flowers, then prune it after it drops its leaves. If you want to favor the flowers, then prune right after bloom. Both Texas ranger and rosemary bloom on current growth, summer flowering, so they can also be pruned in the winter months.

Bob Morris is a horticulture expert living in Las Vegas. Visit his blog at xtremehorticulture.blogspot.com.