Do Your Plants a Favor. Woodchip (Wood chip) Mulch Available!

 North Las Vegas, Nevada.

Wood Chip Mulch: Fully stocked! open at 8 AM for load-your-own! Please bring your own tools and containers! Drive around the west side of the property to the mulch piles in the back, Please wear a mask if others are around. Pick-up trucks can be tractor loaded from 8:30 -11:30 for a $5 fee. For more information call 702-257-5555.

This is what you see from Horse Drive.

This is where it is located in North Las Vegas.

This is what woodchip mulch will do for your fruit trees. Notice those with woodchip mulch applied vs. those NOT with woodchip mulch applied to the soil surface after planting.

Rose Flowers and Buds Look Terrible in the Spring

Q. One of my roses wilts even though it’s getting watered regularly. It does get morning sun. My other roses do not do that. What’s going on?

Tough to tell because thrips are so small but this looks like Western Flower Thrips damage to roses. of the flowers and flower buds wont open and if they do they look horrible AND its in the spring....suspect Western Flower Thrips (WFT).

A. This sounds like Western flower thrips damage to the rose petals. Thrips are very tiny insects that rip and shred rose petals to smithereens. You cant see them unless you use a magnifying glass. They will spend the winter, waiting, for new growth to come out before they attack. As soon as the rose buds form, they attack the soft petals.

Thrips rip and shred soft plant tissue and “lap up” the fluids released by the rips like a dog “lapping up water from a bowl”. When these insects are in high numbers, they attack rose flowers while they are still in their buds causing them to remain closed, never to open, but damaged. They also attack nectarine fruit when they are very small causing scarring of the fruit.

Western Flower thrips also attack nectarine fruit causing scars and sap dripping in crystals from the fruit. Sometimes the damage is so bad from high numbers that the fruit is inedible.

            The usual remedy is to remove all the flowers and rid the plant of this pest land then spray with a dormant oil if it is early in the season. But Spinosad sprayshave been effective in keeping thrips at bay. It doesn’t kill them like other more toxic sprays do but is a safer alternative because Spinosad is considered a “natural” product.

Sticky Roses in the Spring and What to Do

Q. I have roses with sticky leaves from the aphids feeding on them. I need to get them under control before they start to become a problem. I found some Insect and Disease Control sprays at the nursery that have worked in the past. Any opinion about them?

Aphids in the spring on rose buds, leaves and flowers suck plant "juices". From these plant juices sucking insects like these aphids release a sticky "honeydew" that full of sugar that attract ants and bees. 

A. They do work and if you’re not opposed to using insecticides then use them. If you look at the list of ingredients, those pesticides which control insects and others used for disease control contain both an insecticide as well as a fungicide. You usually do not need both ingredients.

            In climates where the humidity is high (not the Mojave Desert), rose diseases like black spot, powdery mildew and botrytis are prevalent. In these climates, it’s probably a good idea to apply a multipurpose insecticide plus fungicide spray. In our climate, diseases are less of a problem due to our lower humidity. If it were me, focus on an insect control chemical rather than a combination of two chemicals in the desert. Why apply a fungicide if you don’t need to? 

Woodchips Vs. Rock. Which Do I Chose?

Q. You mention woodchip mulch instead of rock on the soil surface for plants, but I find woodchips provide sanctuary to roaches and other pests that cause other problems. For this reason, I prefer to use rock.

The value of woodchips are they rot when wet and provide nutrients to plants. They don't provide any nitrogen. They aren't green but they do provide other nutrients which add organics back to the soil.

A. The main value of woodchips applied to the soil surface instead of rock is to provide “organics” back to the soil as they break down or decompose. Rocks will break down, but they end up “mineralizing” the soil instead of adding organics back to it. This “mineralizing” may take 3 to 5 years after planting, but some plants will become yellow during that time while others do not. Some plants grow best when organics are continuously added back to the soil instead of minerals.

Woodchips rot when moist and change the color of the soil from light brown or tan to dark brown.

Insects like roaches and pillbugs are “decomposers” that help break down woodchips into smaller pieces; earthworms are frequently next in this process followed by microorganisms like bacteria and fungi which further break them down into plant nutrients. If you have a lot of woodchips applied to your landscape, expect to find a lot of decomposers as well. These “nuisance critters” must be managed so they don’t become a problem or they might.

Plastic irrigation boxes attract roaches and spiders when surrounded by woodchips and wet. An occasional insecticide spray in the box will control these nuisance insects.

            These “nuisance critters” are attracted to water, food and warmth. Use your favorite insect spray inside irrigation boxes and keep woodchips from two to 3 feet away from the foundation of the home. Applied water shouldn’t be any closer to the foundation than this anyway. Remember, plant roots follow where the water is applied. No applied water, no root growth.

            Your home is inviting when the outside temperatures are uninviting. During late spring and early fall, apply a “barrier spray” to repel these insects away from your home. Your favorite barrier spray applied to the foundation of the home helps repel “nuisance critters” when they need a change in temperature. The same principle applies to strawberries and other soft fruit like tomatoes touching the ground.

Saving a Favorite Peach by Grafting

Peaches can be grown on their own roots by cuttings or by seed. Of course growing a peach from seed introduces all sorts of diversity that you may or may not want. If this is a favorite peach then vegetative propagation....propagation without sex...is preferred. Vegetative propagation be done through the rooting of  cuttings is probably the best and easiest to do if their own roots are good enough for its natural size or location. Rootstocks may be selected for decreasing the size of the mature plant, disease resistance, high salts in the soil and other reasons. For peaches the most usual reasons are for different soil types.

Grafting and Budding

Sometimes grafting the plant is recommended. Commercially, grafting the old fashioned way (side grafting, approach grafting, bench grafting) is seldom recommended. Instead, a practice called "budding" is preferred. Budding removes (cuts) a bud from the desired tree and inserts it into the seedling of another, the rootstock. This inserted bud is wrapped in stretchable plastic until new growth coming from it is seen. Once you are sure it is growing strongly and will not die, everything above this new growth is cut away....removed. The new plant is a "grafted" peach tree consisting of its rootstock and new growth (scion). 

Wine grape grafted onto a rootstock selected for soil types and disease resistance.

Remnants of this "graft" is called a "dogleg" that may visually disappear in a few years.

Dogleg resulting probably from budding.

Preventing Olives from Forming Using Olive Stop

 This is the label information on Alco Olive Stop.

Please read what I copied from the EPA in 2012 on this label and I will give you a condensation of what it says at the very end. What I tell you here does not replace the information on the label. The label of any pesticide is the legal information provided by the Manufacturer and is the most recent information.

Label Information

For Ornamental Olive Flower and Fruit Elimination For best results ALCO OLIVE STOP should be applied when the olive trees are in full bloom and before fruit set has occurred. During periods of extended bloom more than one spray will be necessary to achieve total flower elimination. When extended bloom occurs the first application should be made between 1/2 and 3/4 bloom with a second spray made 7 to 14 days later. If necessary a third spray may be made 7 to 14 days after the second application. In desert or extremely dry areas all fruit can be eliminated even after fruit has reached pinhead to small shot size. However best results are obtained when olive trees are sprayed during bloom prior to fruit set. Mix 4.0 fluid ounces of ALCO OLIVE STOP in 10 gallons of water. To ensure proper coverage add 1/2 to 1 fluid ounce of any suitable non ionic wetting agent to each 10 gallons of spray mix. ALCO OLIVE STOP can be applied through any conventional spraying equipment. For broadcast use olive trees can be treated at rates up to 96 0 fluid ounces per acre per treatment (up to 0.33 lb of 1 NAA equivalent). Do not exceed 96.0 fluid ounces (0.33 lb of NAA equivalent) ALCO OLIVE STOP per acre per season. 

Rates for Ornamental Pear and Ornamental Plums

For Fruit Elimination in Ornamental Pears and Plums make a single application either at full bloom or during the period up to 5 days following full bloom. Apply to achieve full coverage. Mix 3.0 fluid ounces of ALCO OLIVE STOP in 10 gallons water. To ensure proper coverage add 1/2 to 1 fluid ounce of a suitable non ionic wetting agent to each 10 gallons of spray mix. Spray trees thoroughly wetting all foliage. For broadcast use the maximum application rate must not exceed 32.0 fluid ounces per acre per application (0.11 lb of NAA equivalent) for ornamental pears and plums. Do not apply more than 96.0 fluid ounces per acre (0.33 lb of  NAA equivalent) of ALCO OLIVE STOP per season.

What the Label Says

These directions are only for Alco Olive Stop. The reason for this, other manufacturers have their own labels. The rate or amount of active ingredient may be more or less than Alco's.

Ingredient

The active ingredient that causes "abortion" of the fruit when it is very young is NAA (Naphthaleneacetic acid). It is absorbed into the flowers and leaves where it moves to the base of the ovaries and causes the ovaries and fruit to drop when very small. NAA is a synthetic hormone. It mimics naturally occurring plant hormones called auxins. It is used to abort fruit when they are very young, grow roots on cuttings (propagation), cause flowering to start when it might not, and keep fruit from falling off the tree when it might normally fall off. Olive Stop uses NAA for aborting the fruit when very young. This is the reason it is sprayed on trees when they are flowering. The spray concentration used to do this is very important.

Directions for Use

Determine the amount of water needed by spraying the tree with water before it begins flowering. Spray until water drips from the leaves all through the canopy to be sure all of the leaves (flowers) are wet. Write down how much water is needed for each tree. Wait for the tree to form most of its flowers and then immediately spray when there is no wind or less than 1 mph. Protect vital areas of your body when  spraying by wearing washable rubber gloves, face protection, neck protection, long sleeves long pants, and waterproof shoes or boots. Shower and wash your clothes immediately after applications.

Sprayers

Solo backpack sprayer

On the day the tree is in full bloom, put as much distilled or at least very clean water into the sprayer. When the sprayer is half full, add 0.3 fluid ounces of Olive Stop liquid for each gallon of water. At this time also add a surfactant (sticker/spreader) such as Grow More's EZ Wet, Hi Yields Spreader Sticker, Monterrey's Herbicide Helper or Bonide's Turbo Spreader Sticker. Finish filling the sprayer until the desired amount of finished spray is attained. When the spray is applied, the tree should be in full bloom, i.e., the majority of flowers are open. Spray the tree until the leaves start dripping water.

Hose End Sprayers

Select the spray setting closest to 0.3 fluid ounces of Olive Stop for each gallon of water sprayed. Pour enough of the concentrated Olive Stop into its tank to finish spraying all of the trees. Combine this concentrated Olive Stop mixture with enough spreader sticker to make to make a finished spray. For instance, if you are making three gallons of finished spray then add enough spreader sticker in its tank for three gallons. The amount to use per gallon will be on the label. Gently add the concentration to the spray tank so it is evenly mixed. Spray the tree when most of the flowers are open. Spray until the leaves begin dripping water.

Cleaning the Sprayer

If any spray remains when you are finished, spray the remaining  on the ground over the largest area possible. All sprayers are "triple rinsed" as soon as you are finished. This means the sprayers are rinsed with clean water three times. The rinsate is spread on the ground over the largest area possible. The sprayers are put away after triple rinsing.

Farmer Help on Postharvest Apples in Kyrgyzstan

Recently I did some postharvest work in Kyrgyzstan for ACDI/VOCA, virtually online, with trainings conducted by an experienced local trainer, Azamat Mamytov, through the ACDI/VOCA office head and coordinator Mira Arynova. 

https://www.acdivoca.org/contact-us/

Wbere is Kyrgystan?

https://geology.com/world/kyrgyzstan-satellite-image.shtml

Where in Kyrgyzstan

Picture of Kyrgyzstan and where farms were located. 
https://geology.com/world/kyrgyzstan-satellite-image.shtml

The training was conducted in the area of Kyrgyzstan bordering Uzbekistan and Tajikistan in the Osh and Batken Regions with the capitals in these districts of Osh and Batken, respectively.

Problem

These farmers are producing fruits and vegetables with availability storages due to the perishability of their crops and small size of their farms. Each orchard has an average size of 35 to 100 trees consisting of primarily peaches, cherries, and apples. Farmers are forced to sell their products immediately after harvest even if the price is low primarily due to a lack of cold storage facilities and knowledge how to use it. To add value to their produce, fruit and vegetables must be harvested and stored according to best practices. But farmers have limited knowledge on the best practices to use for the long-term storage of their crops. The lack of storage facilities and knowledge prevent them from increasing their farm income.

Assignment Objective

Workers sorting and grading apples for different markets

The objective of this assignment is to assess the harvesting, grading, sorting, cold storage practices and facilities in two promising villages and provide practical consultations specifically on preserving the longevity of these crops from harvest to market. The US-based volunteer will work with Azamat Mamiyov to prepare trainings on the postharvest practices that best meet the needs of the local farmers and upgrade their current level of knowledge. The US-based volunteer provides technical assistance and aids in the preparation of handouts for these and future participants.

Example of improved storage facility for local farmers.

What was Accomplished?

Because of the trainings made by Azamat and the successes of improved cold storage practices and marketing, approximately 80% of the farmers said they would like to improve their harvesting and cold storage practices. A major roadblock was the size of their operations. Discussions ensued regarding forming informal farmer agreements. Insights were given on what farmers might do to improve the quality of their products being sold. Discussion ensued about forming a formal storage and marketing cooperative among farmers.

For more information on this in Russian contact marynova@acdivoca-kg.org or Bob Morris for the English version at extremehort@gmail.com

Repotting Citrus Trees in Containers

Q. I saw your article in the Las Vegas Review Journal newspaper about renewing soil in a container every few years. I have a dwarf Meyer lemon tree in a large container that's about three years old. It's doing well and I got about a dozen lemons last year. When should I replant the tree?  I suspect winter.  Is that correct?

Citrus can be replanted into larger containers when it gets bigger but the soils should be "renewed" or at least partially replaced every three to five years.

A. It is hard to say when to replant but I should think somewhere between three and five years. Exactly when, I don’t know. It depends on the condition of the soil that was used at planting time and the growth of the tree. 

How to Repot a Citrus

Poor soils should be replaced sooner. Trees with lots of new healthy growth will need soil replacement sooner. Adding fertilizers, only, to the container soil will not improve the soil. Just like in Dust Bowl days it will “wear out” the soil. When the tree shows signs of poor growth or poor color is a good sign that the soil should have been replaced prior to this happening.

Time of year to replant container trees? Right after harvest.

What Kind of Acacia is This?

 Q. I need to replace this acacia tree; in a very shaded area of our yard. Is it a shoestring acacia?

A. Probably not. I posted the Shoestring Acacia flowers below. It is native to Australia and commonly flowers in mid winter in Las Vegas, north of the equator. 

Shoestring Acacia flowers

Most likely it is called Mulga or Mulga Acacia. Check out Mulga aneura from this website in Phoenix/Tempe.

http://www.public.asu.edu/~camartin/plants/Plant%20html%20files/acaciaaneura.html

Bottle Trees Dropping Leaves Probably Water Related

 Q. My purpose for writing is that the bottle trees that I planted last year and until now have thrived, have suddenly been stripped of all of their leave at just the very top. The rest of the trees and the leaves look healthy. I live in a very windy area, and my landscaper suggested that the wind stripped the leaves. I have doubts that this is the case since my next door neighbors' bottle trees which are the same age look perfectly healthy. The trees have been been watered on a drip system twice a day, three time a week for the past month. I have 10 trees that look like this. Any advice will be greatly appreciated.

Bottle trees can drop leaves if they are too wet. They grow along streambanks in the dry parts of Australia.

A. From the sound of it and the pictures you sent it sounds more like a watering issue – the soil staying too wet between irrigations. Bottle trees have sensitive roots to wet soils…the roots will easily suffocate if the soils stay wet. This type of overwatering can be seen in the tree by its loss of leaves. Unfortunately we often see the same results when the tree is not given enough water but I don’t think that is the case with your tree.

Right now (Late spring, April) we should be watering trees and shrubs once or maybe at the most twice each week. When temperatures get warmer in about May or June is when three times a week watering is most common. Depending on the soil and its drainage would determine if watering three times a week is okay now. Watering that often this time of year would be okay for very sandy soils with very good drainage.

You can find out if the tree roots are ready for another irrigation by using a soil moisture meter stuck in the soil.

https://xtremehorticulture.blogspot.com/2018/09/use-houseplant-moisture-meter-to-know.html

https://xtremehorticulture.blogspot.com/2018/04/when-to-change-irrigation-clock-and-how.html

https://xtremehorticulture.blogspot.com/2018/12/moisture-meters-and-rebar-tell-you-when.html

https://xtremehorticulture.blogspot.com/2013/07/bottle-tree-dropping-leaves-could-mean.html

https://xtremehorticulture.blogspot.com/2013/05/bottle-tree-with-dying-branches.html

Consult this expert on Bottle trees growing in the Phoenix area:

http://www.public.asu.edu/~camartin/plants/Plant%20html%20files/brachychitonpopulneus.html

 

Wilting Rose Flowers and Thrip Damage

 Q. I am attaching 2 pictures of my rose. One wilts over even though it is getting watered regularly. It does get the morning sun In Pahrump.  My other roses do not do that. Any information you can give me will be appreciated.

I dont know if this is thrips damage or not but it is common on roses in the spring and it does look like this.

A. I think this is thrips damage to the flowers and probably Western Flower Thrips. Try an insecticide containing Spinosad for control. I think your roses have the very small insect called Western flower thrips. Very common now to see thrips on roses. Spray and contain them before they spread to other flowers.

Older Nectarine Dieback Probably Borers

Q. I have a question about the health of my nectarine tree. I had this tree planted 17 years ago and it has thrived every year since…until this year. Normally it is totally covered with blossoms and new growth. This year there are only a few scattered signs of growth. Most of the tree is barren. What could cause this? Is the tree dying?

Nectarines are close relatives to peach. Peach and nectarine are short lived trees primarily because of borer problems in the Las Vegas valley.

A. The most common reason for sudden tree death is borers. Look for peeling or flaking of the bark usually on the west or south side of the tree. They are actively feeding on the trees right now but the dieback usually shows up when it gets hot. 

I see it is in the lawn. Other reasons can be damage to the trunk from lawn mowers or line trimmers and then attack by borers. You might try a soil drench of a borer control chemical from Bayer. Then the trunk needs to be protected from direct sunlight. But if it is peach, that is pretty old for a peach tree. Anything over 15 years old I consider old for peach due to borers. Peach or nectarine. It's the same DNA just the fuzz is missing. They live about the same length of time.

If you use the Bayer product you cannot eat the fruit from this tree until it is no longer applied. It would have to be applied now.

Listen to My Desert Horticulture Podcasts

I am broadcasting my Desert Horticulture podcast though Buzzsprout but you can also find it on Apple Podcasts, Spotify, Google Podcasts, Stitcher, iHeart, Deezer, and many more. They typically last about 20 to 30 minutes and a must for those wanting more information than my blog offers.

Aphid Control on Apple Flowers

Q. I have a Granny apple and Meyer lemon tree. I just saw that I have a bunch of these bugs on the flowers. I would like to know if I should kill them or leave them alone. I also have bees pollinating the flowers so I don’t want to spray any chemicals that may harm them. If I have to remove the bugs is there any way to do it without harming the tree or the bees?

A. Those are aphids sucking plant juices to feed their young. Their numbers will continue to grow until it gets hot. 

Horticultural oil or dormant oil is sprayed on trees and shrubs during warm and windless days in the winter. It eliminates soft bodied insects like aphids.

You missed the winter application of dormant oil or you would have eliminated nearly all of them. Not much you can spray now without hitting some bees once the flowers are open like that. Wait until the flowers have formed apples and then spray. 

Alternative: You can use an oil spray like a dormant oil or soap sprays if it is below about 90F and the flowers are gone and fruit has started to form. Or pull off the flowers and spray and let the flowers reform again later. They will.

A. 

Which Citrus Should I Grow in My Desert Climate?

Citrus is meant for subtropical and tropical climates. Learn which how to select, grow and maintain this type of fruit in our desert.

Citrus grown in the Las Vegas valley

Long-Lasting Effects of Freezing Temperatures

Join me on this episode of Desert Horticulture. I discuss the long-lasting effects that spring freezing temperatures can have on plants.

Winter cold damage and bronzing of the leaves

Supplemental Lights Might Not Be Necessary for Citrus Growing in a Garage

Q. Because of the winter cold weather, I move my citrus trees growing in containers into my garage where it never gets below 40.  I added three fluorescent lights fixtures with grow lux bulbs per light fixture and they are hanging a few inches above the trees. Will this be sufficient light to keep the trees from being starved for light?

A. Although it’s less intense than outdoor sunlight this will work. I’m guessing you keep these citrus trees in your garage all winter long. But I’m wondering if you even need all that!

Interior of a peach flower showing the ovary. A fresh, good looking ovary after a possible freeze tells you it will probably produce a fruit.

           Winter freezing temperatures low enough to kill flowers normally start around mid-December. Usually by mid-February these temperatures are over. Although rare, sometimes we never experience freezing temperatures anywhere in the valley. Infrequently these temperatures are “patchy” and can start in mid-November (as they did in 2020) and can stretch into mid-March (as they did in 2021).

Recording Thermometer 

Inexpensive recording Taylor thermometer with two temperature probes. It used to run about $12.

Accuweather app for cell phone

Do you see why I recommend putting a recording thermometer in your landscape! I also recommend downloading a weather app on your phone for predicting upcoming freezes.

Different landscapes experience different temperatures. Oftentimes these different landscapes follow different weather patterns. These weather patterns determine your level of success in our climate. It would be much simpler for growing citrus if our climate was colder or warmer. But it’s not.

Low Light Levels Can Substitute for High Light Levels

I’m also wondering if your citrus even need the extra light. If temperatures are cold in your garage then the entire plant goes into “hibernation” and there is little need for light. For many plants this “magic temperature” is around 40 to 45° F. Also, the darkness inside the garage can delay flowering.

Because the intensity of light is so low, I would leave these lights on for 16 to 18 hours every day. Long-term low light accumulation can sometimes substitute for short-term highlight intensity (think sunlight). Because of these long light intervals, you might see earlier flowering in these trees.

 

Citrus in Containers? Maintenance More Important

Q. A horticulturalist suggested to put my dwarf citrus trees in the biggest pot I have room for or can afford and they will be happiest there. A person at a local nursery said to not move a tree from a small pot to a much larger pot and suggested the new pot be no more than 2 inches bigger in diameter than the small pot. The two questions seem to be in conflict. What do you think?

The most important practice comes about three to five years after planting into the container; replacing soil and root pruning.

A. Both answers are acceptable and pot size is not an issue as long as it is big enough. What is more important is the maintenance needed every few years for plants growing in containers. The soil in the container gets “worn out” and the roots need to be trimmed. Perhaps think about these containers like an aquarium; every few years plants in containers need to be removed, fresh soil added, the roots trimmed, and the plant repotted. This maintenance practice reinvigorates the plant and helps it live longer with fewer problems.

Selecting Citrus for Containers

Calamondin, or calamansi in the Philippines where it is native, is a small citrus that is suitable for containers. But it is sensitive to winter freezing temperatures.

When selecting citrus trees for containers make sure the tree is a dwarf or smaller in size. Smaller citrus like lime trees, calamondin, and kumquat, although variable in how much cold they can tolerate, are naturally small in stature. Oranges, lemons and larger citrus on dwarfing rootstock can also work but may be difficult to find. Look for the word “dwarf” on the label.

Containers Get Hot in the Desert

Also important is the transfer of heat from the sunny side of the container to the roots. Temperatures in the summer can be 170°F on the exposed side of the container. Consider growing container plants inside another container so the inside container is protected from direct sun by a fancy decorative exterior container. The shade from the exterior container prevents the sun from heating up the interior container.

Shade Cloth Needed for Lemon Trees?

Q. I just planted a Lisbon and Meyer lemon in full sun. Do I need to put shade cloth over them in the summer? I put shade cloth over my raised bed vegetable garden. They are planted along a northeast facing wall and not surrounded by rock.

Eureka Lemon growing in Las Vegas. Eureka lemon is a true lemon.

A. It’s a good location for fruit trees but I’m not sure how your citrus will perform in your landscape locale. Its touch and go in our climate. Much of their performance depends on the winter and spring temperatures of your landscape location. If temperatures are very low during the winter, Lisbon and Meyer trees might both get killed. Meyer lemon is more cold hardy, but in a very cold location, or during a very cold winter, it can be damaged or worse. If there are spring freezing temperatures, you might see less or no fruit produced on one or both trees.

Probably Meyer lemon which is not a true lemon. It doesnt have that lemon shape, it is round instead, and it shows off its orange heritage when it ripens but still tastes like a sweet lemon.

‘Lisbon’ is a normal lemon tree. ‘Meyer’ is not. Meyer lemon fruit tastes like a lemon but is actually a citrus hybrid with sour fruit. ‘Lisbon’ is 5 or 6 degrees more tender to winter freezing temperatures than Meyer lemon so it may need winter protection in your landscape locale when Meyer doesn’t.

Shade Protection?

Citrus doesn’t need shade protecting it from our desert sun. Citrus grows in full sun in the Yuma area, so it doesn’t need shade cloth here either. However, the first year after planting it might be a little shocked from its transfer from coastal California nursery to the harsher Mojave desert so it may develop some leaf yellowing or leaf drop the first year. Give it a chance to acclimate to this desert area which is no worse than growing in Yuma if the soil is improved at planting.

Minneola Tangelo. Orange, Pomegranate Not Producing Fruit

Q. I've had a dwarf Minneola Tangelo tree for about 4 years that gets morning sun, but I've gotten fruit off it only once. I've had an orange tree for about 1 year and a half that gets full sun; it had blossoms, but they all fell off before the heat of summer even began! I planted a pomegranate tree in full sun this past Mother's Day.  When I bought it, it had blooms on it; they also all fell off.

Unknown young pomegranate variety after maybe two years in the ground. Some pomegranate varieties are precocious...meaning they produce fruit early while other varieties produce fruit the first year. 

A. There are several different issues with your fruit trees. The Minneola Tangelo flowers only once in January and February. The same will be true of most sweet oranges. If there are freezing temperatures during this time at your landscape locale, then you may get little to no fruit when this happens. When your landscape gets winters with no freezing temperatures then each flower will produce fruit.

Late freezes

           It only takes a couple of degrees below freezing for a very short time to eliminate the flower and fruit. Multiple freezes during the spring results in total fruit loss. You may see fruit from these trees in the future, but it depends on the occurrence of spring freezing temperatures.

Be patient growing most citrus here. Citrus is more productive when there are no winter or spring freezing temperatures such as in Yuma, Arizona. Periodically we get winter freezing temperatures that can outright kill different types of citrus trees. The only reliable citrus for producing fruit in our climate are the so-called kumquats. This is because they are very cold hardy and flower all through the year.

Not Old Enough

Pomegranate loss of fruit is a different story. Pomegranate flowers through most of the year because the flowers are produced on “current season wood”; new growth and not last year’s growth. Some pomegranate varieties are more precocious than others and you will see fruit the first year they are planted. Other varieties produce fruit in the second or third year after they are in the ground. Just be patient and they will produce fruit. Plants frequently produce flowers but no fruit when they are young. It is an indicator that next year they may start fruiting.

Check Flowers of Fruit Trees for Freeze Losses

Myer lemon (not a true lemon) fruit ready for harvest. Its orange color and round shape shows off its orange fruit heritage.

Why doesn’t my ‘Meyer’ lemon tree produce any fruit? 

I was reminded of this question when I estimated the fruit production this year in a Las Vegas Orchard. I use a particular variety of pluot called ‘Flavor Supreme’ as an “indicator tree” for predicting the probable fruit load that year. I saw no fruit developing and I saw no remnants of flowers on these trees. I knew there was a late freeze that came through that orchard during the spring, probably two or three weeks ago.

Tearing open a flower soon after suspected freeze damage will tell you if the fruit will fall off dead or it is alive. In this case the ovary inside is green so it shows the flower will most likely produce a fruit.

           How did I know all that and how do I relate it back to ‘Meyer’ lemon? First of all, recognize it only takes a 1 or 2°F difference in temperature between having a tree loaded with fruit versus having a tree with few fruit. If this temperature difference comes along two or three times during the spring when it’s trying to flower, then voilà, there is no fruit produced that year.

All Flowers are Sensitive to Freezing

           The most tender parts to freezing temperatures of any fruit tree is its flowers. When flowers are open is the time when it is most sensitive to freezing temperatures. The tree itself is usually fine but not the flowers. If a very light freeze occurs in the spring only once when the tree is flowering, then fruit production is reduced. If a light freeze happens two or three times, maybe a week apart during the spring, then the fruit is probably eliminated for that year. However, if there is a single “hard” freeze (4 or 5 degrees below freezing or more) as flower buds are “awake” then, most likely, all fruit will be eliminated for that year.

           Flowers are killed by freezing temperatures depending on their stage of development. Flower buds during the dead of winter are very tolerant to freezing temperatures. But in the spring, when the plant begins to “wake up” from its winter sleep, they become more and more sensitive to freezing temperatures as they approach opening.

Open flowers are the most sensitive to freezing temperatures; 1°F below freezing for a very short time kills the single chance it has for fruit. Once a flower dies, it cannot produce fruit. If the flowering time of a fruit tree lasts three weeks, then it has a better chance to produce fruit as more flowers continue to open. If only 5% of the flowers are needed to produce a full load of fruit and all the flowers are dead, there is no fruit for that year.

Pollen Alert and Hay Fever

If bermudagrass flowers like this one are left to release pollen in the air, they will cause "hay fever". That's why common bermudagrass is not permitted for planting in Clark County, Nevada.

Pollen Alert

That’s what we see on our advisories in the early spring regarding pollen from mulberry, ash and junipers. The pollen alert continues through the “pollen season” as we go from mulberry to pine to olive. Pollen season might last until May. Right now we’re in “mulberry season”. Some pollen like mulberry is light enough and can be pushed by the wind and carried by pollinators like honeybees. This type of pollen causes “hay fever” while others are considered “sticky” or “heavy”, too large to travel long distances in the air and not considered allergenic.

Male flowers from the 'Bonita' ash tree. Because this ash tree is male, it produces only male flowers. Great for producing no seed but not if you dont want pollen.

Hay Fever

            “Hay fever” was a misnomer from the start. It was an old historic association with the cutting of hay in the spring and not paired with flowering of plants that cause the release of pollen. Back then pollination by plants was not studied much. Tree and shrub pollen was not considered responsible for “hayfever”. Most allergenic pollen comes from uncontrolled, wild grasses growing where rain was available. These allergies were caused by pollen floating in the air but the idea of “pollen fever” never caught on. Until recently people with severe symptoms were told to move to the desert Southwest where “pollen fever” was never considered much of a problem. Maybe that was the case back then, but they are wrong now!

Common bermudagrass flowering and it will seed next spreading pollen and seed everywhere. When bermudagrass escapes mowing, it creates pollen, allergies and seed.

Desert and Hay Fever

            As people moved to the desert Southwest and started planting more and more “desert trees” like Acacia, Mesquite and Palo Verde, “pollen fever” (aka, hayfever) developed into more of a problem. Typically, trees and shrubs with large showy flowers like oleander do not contribute much to the “hayfever problem”. This pollen is heavy or sticky and did not travel in the air far from the flower and the plants released pollen too large to cause “allergy problems”. Most of the “problem pollen” comes from “non-showy” flowers commonly found on olive, mulberry, pines, ash trees, mesquite and the like.

Oleander flowers are quite "showy". Showy flowers are not typically allergenic because the pollen is large and/or sticky.

Planting Restrictions

            Now we have planting restrictions in population dense Clark County that prohibit the planting of male mulberry trees or olive trees that produce lots of fruit. So, is it “illegal” to plant mulberry trees in Clark County? Yes and no. It is “illegal” to plant male mulberry trees but not the female trees.

Mulberry flowers are called "catkins". Flowers in mulberry are like ash trees; they are either male or female depending on the sex of the tree.

How about olive trees? Yes and no, but for a different reason. Olive trees always have both male and female parts in the same flower so we focus on the so-called “fruitless mulberries” and hope that these trees reduce “hayfever” in large communities. Mulberries, similar to ash trees, are bought as either male trees or female trees. As I have always said, plant sex is much more interesting than animal sex because of its diversity.

Olive trees are both male and female so their flowers, unlike mulberry and ash, contain both male and female parts. 

Making Pineapple Guava Set Fruit

Q. Does pineapple guava need a pollinator plant to produce fruit? The edible flowers bloom in May and have the wonderful taste of cotton candy! Should I get my pineapple guava tree a boyfriend?

Flowers of Pineapple Guava

A. First, let’s talk terms. A pollinator is an insect that helps plants produce more fruit by transferring pollen from one plant to another. Examples of pollinators are honeybees. A pollenizer is the plant that supplies this pollen to another plant to help it produce more fruit. So, I think you are asking for a pollenizer plant for pineapple guava.

A pollinator, honeybee, visiting a peach flower and it will encourage fruit set.

Now let’s talk pineapple guava. If the flowers are pollinated properly by a pineapple guava that is not exactly the same as the mother plant (pollenizer), the flowers will produce fruit. Some plants may be even self-fruitful to a degree. The amount of fruit produced depends on the number of flowers it produces and closeness to a pollenizer plant.

To make sure to get fruit from the flowers, give the plant a “boyfriend” (or girlfriend). The reason for this are because of its genetics. In technical terms, the flowers can be non-receptive to pollination by the same or similar plant (variety or cultivar) depending upon genetics. So to make sure you get fruit, plant two different varieties of a pineapple guava in close proximity, otherwise it might be a trickle of fruit at best. The flowers of pineapple guava are edible and the taste is not affected by a pollenizer.

Pineapple Guava and the Desert

Pineapple guava performs well in desert landscapes. They can handle our heat and they can handle our cold. They can even handle a lot of the rock mulch used in many landscapes. But they are “normal” water users (mesic) and not xeric like many of our native desert plants.

Flowers of pineapple guava with the same genetics are "self infertile"... in other words as much as the honeybee visits these flowers they will not set fruit. Even if the honeybee visits other pineapple guava, if they are too similar genetically then they will not create fruit. But the flowers are still yummy!

Pineapple guava is a good choice for our desert climate in landscapes, but they are not true “desert plants” so they grow better with a little bit of organics like compost mixed in the soil at planting time.