Central Growth Bright Yellow in Palm

Q. Hello, I'm hoping you might offer a suggestion for a sick/ugly palm tree.  I have a Mexican fan palm in my back yard in Mesquite that was planted from a 24" box nearly five years ago (in December, by the way).  About this time last year, it developed what I called the "bald man" look, with the top fronds curving down much earlier than normal, leaving only the emerging (newly opened or unopened) fronds sticking up.  When they emerged, they were a uniform yellow color - the older fronds' color is fine, except for the curved stalk. 


When summer came this year, it returned to normal and looked great all summer.  Now, it is doing the same thing again this year.  Coincidentally, last year and this year were the only times it's produced the strands of seeds/berries.  If it's going to look terrible during the cooler months (which is when we are at this home), I'm probably going to have it removed and replaced with something else.  Before I take that drastic step, I thought I'd see if perhaps you could offer suggestions to "cure" this problem.I thought I'd write for your advice and include a photo.  I'd appreciate any suggestions you can make.

A. That sort of yellowing in the growing point of the palm is usually a sign that the central bud is going to die. Once the bud dies of a single trunk palm, the palm dies. The fact that it was yellow and recovered kind of surprises me. It is usually an indicator that the central bud is diseased.

This is a queen palm with new, immature fronds coming from the central bud.

On another note, Palm trees should never be planted during late fall or the winter months. They usually have a higher mortality if planted during this time of the year. The best time to plant them is when there is good weather for a couple of months after they have been planted. Typically palm trees do quite well when planted during the summer months. If you want to try something, you can use a fungicide poured over the top of the central Bud to see if you can arrest the problem.

Another possible problem could be nutritional. I would apply some iron chelate around the base of the tree and water it in now.

Another palm, one of the date palms, with the central fronds coming from the bud yellowing.

Another possible problem might be keeping the soil too wet or the soil might not be draining water very well. Soils that hold too much water can cause this type of yellowing as well. Even another possibility might be that the palm was planted too deeply. If the palm was planted more deeply than it was growing in a nursery then you can develop yellowing like this as well. Make sure the soil drains easily. If the palm may have been planted too deeply or is in a low spot in the yard, you might have to move it somewhere else where the water does not accumulate.

Thirdly, apply a landscape fertilizer in the spring or late winter along with an iron chelate. The iron chelate should contain EDDHA as the chelate in the ingredients.

Rose Leaf Scorch Probably a Soil Problem

Q. I have some roses doing poorly. Any thoughts?

A. If I see it correctly, it looks like rock mulch in the background. No, no, no for roses. This leaf is showing leaf scorch and marginal tip dieback, a sign of fertilizer, soil and water conditions. They are all inter-related.

The first thing we need to consider is soil improvement. In our desert soils they need massive amounts of organic material to bring it up to the bare minimum of 3 to 5 % organic matter for plants like roses. Our soils in Las Vegas are typically around 1/10th of 1% organic matter. Organic matter breaks down over time so to accomplish a 1% change will mean about a 25% volume of compost added to the soil at the time of planting.

Surface mulches made of wood mulch like the kind made from chipping trees will contribute organic matter back to the soil and replenish what is lost over time. Bark mulch will not contribute much of anything. It is decorative only.

Water should be about two to five gallons at each watering. Watering frequency with surface mulch is about three to four times per week, basically every other day. In the winter this might be every ten days.

Fertilizers should be one that promotes flowering, adequate in phosphorus, and balanced with all three numbers present. The first number, nitrogen, should be a relatively high in number. Potassium, the third number would be anywhere from half the value of the first number all the way up to an equivalent number. This would be applied in January or just before or during when new growth commences. Iron chelates should be applied at the same time. Small amounts of fertilizer can be applied every four to six weeks if these are for show. Rosarians suggest the application of magnesium in the form of epsom salt.

You Will Not Protect Bougainville from Freezing by Feeding Them

Q. Before the first freeze here in Las Vegas, probably in 3-1/2 weeks, what may I feed them?  Might there be something simple, without figuring amounts and all kinds of mixing? I have three plants, all in the ground.  They are six years old this year, and I wrap their bases before the freeze. They always come back come March/April, and bloom beautifully in August/September through October – when the real heat hits.

A. I like your idea of wrapping the bases of the plants before any freeze. Unless you have a very warm microclimate in your yard, and there are some of those in Las Vegas, you will see damage to them at the first light freeze with temperatures below 32° F. The harder the freeze and the longer it lasts, the more severe the damage.

Bougainvillea after freezing weather in Las Vegas

Wood mulches will also protect the base of bougainvillea but wrapping it is more effective. This way when it freezes it will kill the top of the bougainvillea to the top of the mulch or wrap and not any further.

Of course this works to temperatures below freezing for short periods of time. If the temperatures are extremely cold, or if these temperatures last a long time, then it will freeze the plant to the ground. How well you protect the base of the plant will determine how strong it will come back, or not, next spring. Having bougainvillea in a spot in the yard which does not have a lot of wind and is very close to a warm, South or even better yet, West-facing wall will improve its chances for survival.

Freeze damage hits the youngest and thinnest plant parts first during a light freeze and the part of the plant most exposed to wind and less protected by warm south or west facing walls

Plants that freeze to the ground will come back like gangbusters next spring because of their established root system. Plants that are first planted have to grow both the roots and the tops and so growth is divided between the two. Plants that have an established root system and freeze to the ground only have to grow the top back. So all of the spring growth is funneled to top growth so we see huge amounts of top growth in the spring.

Spring recover of oleander from a winter freeze

You do not want to feed them anything this time of year. Just make sure they get watered. This goes for any winter tender plant. These plants should get no fertilizer applied to them that promotes growth any time after mid-August. Fertilizers which stimulate new growth will cause the plant to become more succulent and lower its chances of surviving winter freezes. This is not true of plants that have no problem surviving winter freezes. In fact, those plants can receive mid fall applications of fertilizer with no problems. A mid fall application of fertilizer can substitute for a Spring application but not winter tender plants.

Philippines Tragedy

Some of my subscribers know that I have a family farm in the Philippines. The typhoon passed to our south and we avoided major damage. Those to our south did not. We are in the process of aiding and doing what we can to help our neighbors. We will not know the extent of this tragedy for awhile, that is the way it is in the Philippines. Right now power can be "iffy" for awhile.

Filipinos are resilient people and face tragedy on a recurring basis. The Philippine Islands receives 20 typhoons each year and most people are not aware of every typhoon but this one was different. Just last month this same area was hit with a devastating earthquake equaling the energy of 30 of the bombs dropped in Hiroshima that brought the end of  WWII in the Pacific. This typhoon was much, much worse.

I will do my best to keep those of you interested, posted. Thanks for all your emails and phone calls. They are appreciated.

Bob Morris
Extremehort@aol.com

Entrance to MoCa Farm, Bgy. Castillo, Padre Garcia, Batangas, Philippines

Dethatch Bermudagrass Just Before Overseeding or in Mid-Summer

Q. Is it too cold to dethatch my Bermudagrass lawn?  Do I have to wait until next year now? What about overseeding; too late also? If I need to wait, then when?

A. It is not too late to dethatch in Las Vegas. Dethatching, sometimes called power raking or vertical mowing, is the removal of dead, grassy material that accumulates on the soil surface where grasses are grown.

Dethatching machine, power rake or vertical mower

            Bermudagrass is a warm season grass and so becomes dormant or turns brown when temperatures get cold. Bermudagrass produces a lot of this thatch or dead grassy material, more than most grasses. If this thatch is not removed regularly the appearance of a lawn will decline.

            Years ago it was burned in the fall. In some rural areas it is still permitted.

            In place of fire we use machines that pull the thatch from the lawn. This thatchy material is then disposed of. The best time to dethatch is when the Bermudagrass is actively growing in the summer months or just before overseeding.

Thatch

            Overseeding is planting a new lawn of cool season grass, such as ryegrass, in the fall just as Bermudagrass is becoming dormant. Thatch will interfere with the seeding of a winter lawn in Bermudagrass. Dethatching the Bermudagrass just before overseeding is commonly done for a better looking winter lawn.

            Dethatching now won't affect your Bermuda lawn but you are getting a bit late for the ideal time to overseed. As temperatures get lower, it takes longer for cool season grass seed to germinate. The ideal time is mid-September through mid-October. Later than this can be a little chancy because we don't know what the weather will do.

How thatch accumulates

            It is warmer in the city than in the suburbs so overseeding in the city is more successful later in the fall. As you get closer to the desert or higher in elevation overseeding should be done earlier.

            If you miss this time for dethatching, the next best time would be June July and August.

Trees Planted in Grass Need Extra Water

Q. I had a 3 year old mesquite tree in my front yard that just blew over in the wind today.The original landscapers planted a tree without a drip system. I have an area of grass around the tree and they told me in the past that that is sufficient to water a tree. Today the landscapers that came to cut down the tree told me it fell because of the roots being at the surface. Do you recommend putting in the drip line? I can tell you the soil under the tree was very moist from the sprinklers. I have attached a picture of the felled tree. Any suggestions for a tree that would be sturdy to the wind? The original tree planted was a glossy privet that died after the first year. It was replaced by the mesquite. I have to plant something in the 24 inch box size per HOA rules.

Mesquite tree that blew over

A. I am sorry to hear about your tree that blew over. This can be a problem sometimes with trees that are planted in or near lawns and rely only on lawn irrigation. Lawns require shallow irrigation that are frequent. Trees and large shrubs require a larger amount of water applied less often. Be very careful of planting trees that originate from deserts and used for desert landscaping (examples are acacia and palo verde) planted in the lawn. This usually does not work well. Trees that are suited for lawn areas are those that are not desert trees.

Trees and large shrubs getting water only from the lawn will fight for the shallow irrigations of the lawn. If you are an efficient lawn irrigator, the tree will have a difficult time getting the deep irrigations it needs for deep rooting. When trees are planted in large turfgrass areas, such as golf courses or parks, the trees always grow faster and perform better if they are supplemented with water for the first few years. After three or four years of successful growth, you could eliminate the hose irrigations around the trees except perhaps during the hottest parts of the summer.

Mesquite roots can good deep if given a chance. This is a native mesquite in Zacatecas, Mexico, near a river. The roots had found moisture from the river but not at the surface and so were forced to go deep where moist soil was located.

Some golf course superintendents would send out a water truck once every week or two to flood the area around the tree with water. This encouraged deeper rooting and kept the lawn from robbing the tree of its shallow water supply.

You can do the same thing with a hose. When a tree is planted in the lawn area it is best to leave a shallow depression around the tree 3 to 4 feet in diameter. This can be a basin for flooding the area around the tree every week or two with a hose. It also helps, as you have done, to keep that area free of grass and weeds. If you can remember to water with a hose, particularly during the heat of the summer, you can save yourself the expense of installing a new drip line.

Mesquite trees are what we call riparian tree species. Unlike Palo Verde or acacia in the desert, Mesquites are only found near waterways. They grow when water is available and stop growing when water is not. When water is constantly available, they constantly grow. When Mesquites get water they can grow quite rapidly, as much as 8 feet in a single year. 

Honey mesquite with mistletoe in the Mojave Desert in North Las Vegas

This is a problem when they receive constant watering because their tops grow faster than their roots and this contributes to blow over. For this reason Mesquites are not a good choice for a lawn area but are more appropriate for a desert landscape. In lawn areas stay away from desert trees. Trees like many ash, Locust, honey locust, privets, and others are not desert trees and they will survive in the lawn much better.

Personally, I think you are better off without the lawn unless you have a use for it. You can substitute green groundcovers and achieve a similar look to a lawn. When you plant trees and you do not have a lawn make sure that you surround the trees with some smaller shrubs to help keep the trees irrigated. Focus on smaller trees that are in scale to your home. Don't put in 40 foot trees if you have a single story home. 

Take advantage of the shade they give and put them so they shade the south and west walls and provide shade to where you have outside activities. Trees should probably not be planted just for looks in the desert. They should also have something to contribute to your comfort as well. So remember to keep your trees small, use desert adapted trees whenever possible, minimize the use of tall trees and shrubs to reduce your water use and to make sure they contribute to your home environment and your outside living environment.