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Friday, January 17, 2020

Desert Horticulture Podcast: Verticillium Wilt on Desert Willow, Soil Amendments for Raised Beds, and Planting/Managing Palo Verde Versus Crepe Myrtle

Join me in this Desert Horticulture Podcast where I discuss the possibility of branch die back due to Verticillium wilt in Desert Willow, different soil amendments that can be added to soil mixes and your garden, and planting/management differences between Desert Museum Palo Verde and crepe myrtle. All this and more on this episode of Desert Horticulture.

Thursday, January 16, 2020

Viragrow: Mix Soils Together or Get Rid of Soil Interfaces

Viragrow: Mix Soils Together or Get Rid of Soil Interfaces: Q. I dug an area about  5 feet by 8 feet at around 12” deep. I removed all the bigger rocks and mixed remaining soil at around 70% native di...

Viragrow: Mulch Lying Against the Trunk Can Lead to Collar R...

Viragrow: Mulch Lying Against the Trunk Can Lead to Collar R...: Q.  I've had a problem with a cape honeysuckle. I have two plants that are trellised and were thriving (~5 feet tall) until one of them...

Viragrow: Rosemary Oil Effective against Spider Mites

Viragrow: Rosemary Oil Effective against Spider Mites: This is an interesting piece of research done in British Columbia using Rosemary oil against spider mites.The two spotted spider mite is a ...

Viragrow: Featured Article: Good Irrigation Managers Save Wa...

Viragrow: Featured Article: Good Irrigation Managers Save Wa...: This will appear in Southwest Trees and Turf in November, 2014. Avoid Mayhem with Good Irrigation Managers Bob Morris, Consultant fo...

Viragrow: Some Recommended Vegetable Varieties for Fall and ...

Viragrow: Some Recommended Vegetable Varieties for Fall and ...: Here is a recommended vegetable variety list for the Mojave Desert. Some varieties perform better than others under desert conditions. Thes...

Viragrow: Make Your Own Raised Beds for Vegetables

Viragrow: Make Your Own Raised Beds for Vegetables: You can make your own raised beds. It is not hard to do. Using Viragrow garden soil eliminates the rocks that can cause problems for ca...

Viragrow: Viragrow Vegetable Planting Calendar Available

Viragrow: Viragrow Vegetable Planting Calendar Available: We asked Bob Morris, Extremehort, to update our vegetable information for you. Bob has put together a vegetable planting calendar for s...

Viragrow: Leaf Yellowing and Scorch Could Be Bugs

Viragrow: Leaf Yellowing and Scorch Could Be Bugs: Scorchy leaves and yellowing could be lots of things. Check out your discolored and scorchy leaves. This could be a number of th...

Viragrow: Pepper Leaves Curling. Bugs Again!

Viragrow: Pepper Leaves Curling. Bugs Again!: Leaves curling on pepper. Typical pepper leaf curled on the plant. Flip leaf over and we see evidence of aphids feeding. ...

Viragrow: Replenish Garden Soils With Fresh Compost Each Pla...

Viragrow: Replenish Garden Soils With Fresh Compost Each Pla...: Replenish Your Garden Soil with Compost Compost should be thoroughly mixed into your garden soil for best results. Raw (unamended) D...

Desert Horticulture Podcast: Pears, When to Plant Pomegranate and Controlling Whiteflies

Join me in this episode of desert horticulture where I discuss which pears grow the best in the Mojave Desert, the best time to plant pomegranate and the types of damage that whiteflies do and how to control them. All this and more on this episode of Desert Horticulture.

Sunday, January 12, 2020

Selecting the right citrus for the Mojave Desert

Q. My oranges haven’t ripened on my two year old tree. Some are green and others yellowish with very hard skin and last year’s fruit wasn’t very sweet or soft.  Should I cover them tonight? It will be freezing.

A. The fruit of many oranges are damaged at temperatures of 30°F or a few degrees lower.  The type or variety of sweet orange is highly variable to freezing temperatures. If you think winter temperatures will drop low enough for damage, then throw a sheet over the tree to protect it from cold and wind. Go outside at night and look at the sky. Clear skies are more likely to contribute to lower temperatures than cloudy skies. If there is wind combined with freezing temperatures, fruit damage is worse.
Fully ripe citrus in the Philippines
            They may not be ripe yet. Depends on the variety and time of year. Cold weather can get them to turn orange when they ripen. Oranges in warm climates never turn orange but they are ripe and it is acceptable. My guess from their color is they should stay on the tree longer. Oranges are tropical to subtropical and are not intended to be grown where it freezes. If they are sweet they can handle SOME temps down to about 28F or so. We grow ours in US in Yuma, Az, Corpus Christi TX, south Florida and southern California where it seldom freezes. If it does freeze farmers have crop insurance.
             Ripe fruit handles temperatures a couple of degrees lower than unripe fruit during freezing weather because of their higher sugar content. The sweeter the orange, a couple of degrees lower in temperature is needed to damage the fruit.
            Our desert climate creates winter temperatures too low for growing and producing citrus. You might have a couple of warm winters in a row followed by low winter temperatures that wipe out the citrus.
            Citrus growing areas have warmer winters than Las Vegas; places like Yuma, Rio Grande Valley in Texas, mid to South Florida and lower elevations in California are the US premier citrus growing regions.
            Will citrus grow here? Sometimes, depending on where they are planted and your choice in citrus. Will they produce fruit here? Sometimes, depending on when they flower and the temperatures just before and after flowering and food production.  
            Talk to your neighbors and look around your neighborhood. If your neighbors had luck growing oranges, you might have the same luck. Be suspicious of neighborhoods that have no citrus growing in them at all. There might be a weather and climate related reason for that.
            Pay attention to the type or variety of orange you have. Your calling yours an orange. It has a name or variety besides “orange”. These different varieties of oranges flower and are harvested at different times. Some perform better here than others.
            The “University of Arizona” has published a fact sheet that you can retrieve online called, “Low Desert Citrus Varieties”. Use your favorite search engine and type in what I have here in quotations and look at the last two pages. It will tell you the harvest time for these fruit. Avoid those varieties which should be harvested in the middle of December or later in the winter.
           Take a look at the last page of this document from the University of Arizona. They can be ripe any time from October through March depending on the type of orange and growing conditions. If it gets really cold the fruit can freeze.

Plant Citrus in the Mojave Desert Just Be Smart About It

I receive quite a few questions regarding growing citrus in the Las Vegas Valley. Some people even accuse me of not telling people to plant citrus here. That’s far from the truth. But you should be aware that there are two strikes against citrus growing well here. It’s your job, after you are aware of that, to make the right decisions and care needed by them.
Calamansi fruit in Batangas, Philippines

            First of all, as I tell a number of my students, when we choose plants that are not 100% compatible with our desert climate then it will “cost” you in personal time,  energy and money to grow them here. That isn’t the same as telling people not to plant them.
            The first strike against them is their port to variable tolerance to freezing temperatures during the winter. Plant them in the warmest part of your landscape and keep them out of the way of cold winter winds. This may require establishing a man-made windbreak on your property to prevent these wins from causing damage.
            The second strike is when they flower. Oftentimes they flower in early spring when very light freezing temperatures are possible. If freezing temperatures occur when they are producing flower buds or small fruit flower and small fruit tolerance to these freezing temperatures are practically nil. This is the primary reason for erratic production of a fruit crop by one of our most popular “lemons”, Meyers, even though it’s one of the most freeze tolerant of the citrus.
            All citrus trees are subtropical. Most do very well on our farm in the Philippines where it is tropical. We don’t have the same problems with cold temperatures that wreck havoc on these trees in our cold desert climate.
            Plant citrus in your landscape and have fun and enjoy their production. But do it wisely. Understand the limitations of your landscape. Find or create “warm pockets” or “cool pockets” where you can grow quality food whether it is vegetables or fruit production. Finding or creating these microclimates will produce the highest quality food possible for you.

Harvest time of citrus University of Arizona

Desert Horticulture Podcast: fruit tree pruning can be done other months than January

Fruit trees can be pruned when there in flower, shortly after fruit set, during early summer and other times of the year. Know which tools you can use and how much you can remove in the desert.