Possible Fireblight Again

 

Although not confirmed this is what fireblight disease can look like on pear.

Dead or dying branches can appear in April or May.

Ah, Yes the Memories

Do you remember the outbreak of fireblight disease about 10 years ago? Fireblight disease can be brutal to many of the landscape and Orchard trees in the Apple family (pome fruit) in an orchard if it’s not caught right away. The hardest hit trees were Asian pear (Hosui, Shinseki, 20^th Century and many others) then the next hardest hit were many of the European pears (Bartlett in particular) and a few apples such as Mutsu and Pink Lady. This disease is extremely virulent. Please check in the landscape Pyracantha, loquat, cotoneaster, Photinia, flowering ornamental pear such as the Callery types.

 

Fireblight disease may not be this obvious to the casual onlooker.

How Does It Spread?

This deadly bacterial disease to plants is spread from plant to plant in the spring when the flowers are open or through open wounds after late pruning. However, this disease is frequently not easily seen until April or May. 

This picture is the common description of fireblight disease; black like it was hit with fire and the prominent Shepard's hook. 

How to Control It

Just because this disease seems to be in remission, don't trust it. It will be back like gangbusters. Prune out the dead wood 12 inches below where the infection seems to be active. When you're done making the cut, sanitize your pruning blades within 70% solution of isopropyl alcohol. Do this after every pruning cut. Then when you have all of your cuttings together, bag them, tie the bag shut and put it in the dumpster far away from the infected plants. Wash your hands, your tools and treat them with a isopropyl alcohol I last time before you put them away.

This disease was tweeted by me. So if you don't subscribe to my twitter account, get it! 

Robert Ll Morris @Extremehort

Update: Fireblight disease is still popping up in May on fire blight pruned Asian pears and their hybrids, many European pears like Bartlett, some apples, quince, ornamental pear, pyracantha and cotoneaster; not on citrus, just the rose family. Where did it come from? Anybody’s guess but it could be your neighbor or at least from the neighborhood. The most effective treatment is pruning it out. But just like removing any systemic disease you have to make deep cuts to get all of it. Cut or prune out 8 to 12 inches below where you see it. Sanitize your pruning blades with alcohol.

Difference Between Algerian and Dancy Mandarin Oranges

Q. I just bought a dwarf ‘Algerian’ and dwarf ‘Dancy’ mandarin orange. The Dancy is doing fine but the Algerian’s leaves are getting brown spots and falling. Is this a pest or disease? I don’t want it to spread!

'Algerian' mandarin (tangerine) with spots on its leaves. One person in Las Vegas growing citrus claims the secret to growing citrus here is soil drainage.

A. Our humidity is so low that I doubt it’s a disease problem. The reason for the difference in leaf brown spots could be its landscape location, adequate soil prep at the time of planting, or the genetics of the plant. The spots are most likely cultural, management; something you have done, or should be doing. Since it happened after transplanting, I’m guessing it has something to do with how it was planted, where it was planted or how the tree was irrigated.

Citrus Origin

            Both trees grow in the subtropics to tropics so make sure the tree was planted with a mixture of compost and soil in a planting hole about three feet wide and about 12 to 18 inches deep. The additions of organics in the soil should darken it. Cover this planting with a layer of woodchips to keep the wood chips rotting, full of organics and moist between irrigations. Make sure it is staked after planting in case there are strong winds.

Landscape Location

            If planting in full sun on the West or South side of a building and it’s showing signs of sun or heat stress, consider shading the tree’s canopy for the first year of growth. Shading doesn’t require shade cloth. It can be done with anything that provides some late afternoon shade. It is probably a good idea to shade the plants from the afternoon sun the first year.

Cultural

            Do not water trees daily except immediately after planting. Daily irrigations are meant only to settle the soil around the roots, not to give the tree a daily “sip” of water. Make sure it’s staked during its first season of growth. During the hot summer months, water as infrequently as every other day if two days of water is applied all at once.

            With a newly planted 5-gallon fruit tree, the tree should receive 4 to 6 gallons of water each time it’s watered. This water should be distributed through three , 2 gallon per hour emitters or four, 1 gallon per hour drip emitters under the canopy of the tree at about a foot from the trunk. As the tree gets larger over time, it needs more water applied over a lager area. Plan for it. Add additional drip emitters (not extra minutes) further from the trunk under the expanding canopy to give it this extra water. When the tree is fully grown at 20 to 25 feet, it should need about 30 gallons of water at each watering.

            Plant these trees at least three or four feet from hot walls and they should handle the reflected high temperatures okay if the soil is amended and they are watered before it gets hot. Fertilize the trees right after harvest with a citrus fertilizer. Prepare the soil with compost and make sure it has good drainage.

Dwarf Types

            Dwarf versions are grafted onto different rootstocks than the standard sized trees. This will impart a slightly different flavor to the fruit. The dwarf version of mandarin orange should get about 12 feet tall and 12 feet wide if unpruned. ‘Dancy’ mandarin oranges (sometimes called tangerines) are the most popular mandarin orange fruit in the world (sometimes called “cuties” in the supermarket). 'Algerian' mandarin oranges are noted for their winter cold hardiness.

What Do "Infrequent" and "Moderate" Mean?

Q. I’ve checked the internet and have some information from our state, but I still can’t compare the terms “infrequent" and "moderate”. Does “infrequent” mean once every two weeks?  Once a month? And what does “moderate” mean? 1 gallon per watering?

Root depth of plants has to do with their size, genetics and the kind of soil. The deepest roots are with large trees, from an arid climate and growing in a sandy soil.

A. I agree those terms are misleading. I think those terms are used by people who don’t understand the differences themselves or they would explain them. "Moderate" amounts of water refers to the amount of water a plant is given. "Infrequent" referst to the frequency of water or how often water is given. These are the two major concepts related to irrigation and are used to schedule any irrigation controller. It sounds like a topic for my audio podcast, Desert Horticulture.

Big Plants Need More Water

            Two concepts should be understood. Bigger plants have deeper roots. Deeper roots are encouraged with "infrequent" watering. This is about how often to give water. Plant roots extract water from the soil deeper and deeper as the soil at the surface gets drier and drier. The surface roots are the first to “suck up” water after an irrigation. The roots take water from the soil deeper and deeper as the soil gets progressively drier toward it’s surface. As we water plants “infrequently”, the roots extract water and grow into deeper and deeper layers of soil. Deep rooting of plants is the main reason good gardeners say, “Water plants deeply but infrequently.”

Get Away from Daily "Small Sips" of Water

            The major reason we do not give plants “tiny sips of water” daily is because this type of watering practice encourages plants to grow their roots more shallow. There is a second reason; tolerance to heat. Plants with deeper roots have a better chance of withstanding the heat of summer.

            “Moderate” amounts of water relates to the amount given to the plant. It usually means enough water to “wet the roots growing in the soil” and little or no more. We learned that the depth of plant roots depends on the size of the plant; bigger plants frequently have deeper roots than smaller plants. The depth of plant roots also varies with the genetics of the plant and the type of soil.

Water "Infrequently"

            The deepest roots are with those plants that are large, have the genetic potential to grow deep roots and grow on sandy soils. The shallowest roots are found on small plants that don’t have the genetic potential for deep roots and grow in a heavy clay soil.

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Ash Trees With Bark Lifting

Q. Our ash trees have “bark drop” as they got older. Should I worry that the light tan areas of bark are peeling in long sheets four feet long, and this bark seems to be coming away from the tree in small chunks?

Bark coming off or lifting from readers tree.

A. Worry only if your ash trees had the bottom branches recently removed and they were planted on the south or west sides of a building or wall. Try to leave the bottom limbs attached to the trunk as long as possible so the trunk is shaded by the limbs. Once the tree has gained some height and age, some of the lower branches can slowly be removed.

Beginning of ash sunburn after it was recently planted. The orangish-red color of the trunk or limbs is not normal for this tree and it was facing the sun. 

            Your job will be to discover if the trunk has been damaged either by the sun or by borers or both. Before you begin, establish which side of a wall or building the tree was planted on and make a mental note. South and west sides of walls and buildings are the hottest and most damaging.

Ash borers in the trunk of a young ash tree. Removing the loose bark will reveal their nasty work.

            Next remove any loose bark including those strips you mentioned. Use your hands first two pull off any loose bark. It won’t hurt the tree. Finally use a sharp and sterilized knife blade about 5 inches long to make the trimming cuts to undamaged wood just below the bark. The undamaged wood should be white or light green. The purpose is to hasten the healing either of the trunk or limbs and discover what did the damage.

Even though this is fruit tree it still demonstrates how to correct borer damage with a knife.

             It’s always a good idea to leave the lower living limbs for shading the trunk as long as possible. This shade helps protect trunk and limbs sunburn. Once these areas are sunburned, they will attract boring insects because these insects are attracted to damaged trees and shrubs. The sun burned areas are in the trunks and limbs where there is the most intense sunlight. This is usually the West or South facing sides or the tops of limbs and branches.

Texas Mountain Laurel Can Make a Medium High Landscape Screen

Q. I had Texas mountain laurel planted in my yard since 1998 and have not trimmed it at all; leaving it to look more shrub-like to act as a privacy screen, between the golf course and our pool.  It blooms profusely, leaving clusters of seed pods.  Would the tree benefit from having the pods removed, or is it best to leave them? Would I get more blooms if I trimmed off the pods?

Texas mountain laurel seed pods are objectionable to some and look fine to others. Prune them off if you dont like them. It will not hurt the plant.

A. Yes, the pods can be removed, and yes it makes more flowers when removed but the trigger for flowering is mostly in the early spring. Many people like the pods formed from the flowers as as well. The primary reason for removing the pods are looks; some people dont like their looks. Some do.

Texas mountain laurel with spring flowers.

            Texas mountain laurel is a Chihuahuan desert native plant so it can make a good heat tolerant 15 foot tall hedge after it is established. It would require about 2 to 4 feet of water applied under its canopy when mature. Remove only crossing branches to give it a full appearance and be careful about “limbing it up”. Let only knowledgeable landscapers prune this plant since it recovers slowly if mismanagement. Plant them no closer than about 8 feet apart. 

        They are relatively slow growing so it makes a privacy hedge that will be slow to fill empty spaces between them. Apply a fertilizer like 16-16-16 once in the early spring to get more and bigger blooms, prune it laterally so that it fills in these empty spaces faster.

What Does Light, Medium and Heavy Mean?

Q. I am confused by the terms, “light, medium, and heavy”?

Desert soils can be confusing. Even though this soil may be difficult to dig, it is a sandy loam soil; a mixture of sand silt and clay but the clay is not present in high enough amounts for it to be considered "a clay soil".

A. These terms usually describe soils, but could also be used to describe watering, such as a “light watering”. A light soil is a sandy soil. A medium soil is a soil has a mixture of sand, silt and clay but still drains water in a few hours to overnight. A heavy soil is a soil that is dominated by clay. It drains very poorly. These “heavy” clay or sticky soils hold water and don’t drain well. Oftentimes planting in these soils is a disaster for xeric plants because of the amount of clay and they hold water for a long time. 

This soil has a fair amount of clay in it. The type of clay makes it "expansive" or not. Expansive soils like this one are considered to have a higher than normal "shrink/swell potential" and cause problems when building or construction. Montmorillonite clay is an example of an expansive clay. Some clays are not as expansive as others.

To make a heavy soil “lighter”, about 90% more sand (v/v) is needed. The other option is to grow plants higher than the surrounding soil so their roots can “breathe”. Small plants need about a foot of soil higher (about 12 inches in diameter) than the surrounding soil. Large trees may need two or three feet tall mounds that are 6 to 10 feet in diameter.

What is a light watering?

            A “light” watering is an irrigation that wets the soil only 3 or 4 inches deep. It might be good for very small plants. This type of watering encourages lots of shallow roots to flourish and makes this plant less tolerant of hot summers. Shallow rooting oftentimes happens with “hose” watering; watering with a hose or a “breaker” at the end of a hose. 

Hose irrigation of corn in raised bed. Water not penetrating deep enough.

Hose watering raised beds and apparent adequate water until examined closely. Water was applied so quickly that it was only getting three or four inches deep but appearing wet, enough for shallow rooted crops but not deep enough for deeper rooted crops like corn. Drip irrigation is a better choice.

To water deeper (a.k.a. medium or moderate) requires watering the same soil about 10 to 20 minutes later but while it’s still wet. This drives the irrigation deeper in the soil and can wet the soil to a depth of 6 to 8 inches. A “deep” watering usually requires some sort of “moat” or “donut” around the plant to capture the water and cause it to go deeper. A third watering like this frequently doesn’t work but requires a “moat” or “donut” instead. Drip irrigation can release the water slowly, so it travels deeper. That’s one of the reasons why single emitter, nonadjustable drip irrigation is preferred in home landscapes and raised vegetable beds.

Giant Argentine Cactus Dying

Q. I have two Argentine giant cactus bought from a big box store last summer. I planted them in the garden soil after I amended it with sand, pumice, and vermiculite to improve drainage. Recently, I saw them with the tell-tale darkening associated with root rot. When the plants were new from the nursery, all branches were firmly set in the pot and upright. Is it usual for the limbs to feel flimsy?  Or, are the remaining limbs soon to rot and bend as well.

Giant Argentinian cactus from reader

A. Argentine giant cactus is a sprawling cactus that gets about 3 feet tall. You can read more about it by googling “Argentine giant cactus” and “ASU”. It’s possible that you might expect erect stems and get sprawling stems instead. Once they are out of their confining container and surrounded by open garden, they tend to sprawl.

Sometimes pumice is used as a soil ingredient for cacti and other succulents.

Root Rot            

It’s obvious to me that your cactus has root rot. It’s either from watering too often or poor drainage or both. In my experience adding too little sand, pumice and vermiculite can cause problems. Most of our soils benefit from additions of at least 80% sand. The vermiculite is another problem. Unlike perlite, it holds water and may make the problem worse. Bottom line, you have to add a lot of sand when you added and use perlite instead of vermiculite if you want to improve drainage.

What to do? 

If you want to improve drainage for cacti then plant them higher than the surrounding soil. These type of cacti require deep but in frequent irrigation. What I mean by that is when you water them make sure the water gets at least 18 inches deep and don’t water very often; maybe twice during the summer and only once during the winter.

Get a working soil moisture meter. 

Inexpensive soil moisture meters made in Asia are sometimes defective. Consider them to be disposable. Check it in the store to make sure it’s working before you buy it. Push the probe in the soil about 3 to 5 inches deep in several locations and water it when the soil moisture meter reads an average of two or three on the scale.

Use Your Eyes

            My observations of cacti tell me when I can water and I don’t use a meter. When their outside “skin” starts shriveling, it’s time to water. Just like any xeric plant, watering them causes them to grow. If you want cacti to grow, water them more often. If you don’t want them to grow much, then don’t water them as often. Always make sure that you’re not watering them so often that it causes root rot. Opuntia from the Sonoran desert I water every three to four weeks for fresh vegetable (nopales) and fruit (tuna).

Reduced Fruit Set Due to Spring Freezing Temperatures

Q. Did you see a reduced fruit set in plums, pluots, and pluerries this year or if it was just mine? I have 3- to 5-year-old trees and this year I just did not see many flowers at all. Not so much lack of pollination, but a lack of flowers. I fertilize with compost and try to keep an eye on how much growth I get each year. I want “fruit production”, not “wood production”.

Lightly squeezing the base of a flower AFTER the petals drop will tell you if there is a fruit present or not. The light squeeze will feel a small BB-sized fruit beginning to develop. Doing it this early tells you if the freeze killed the ovary before the fruit formed.

A. I look at fruit production from now forward to judge how much thinning (or none) should be started in about one or two weeks. Fruit removed should be about the size of your thumbnail. Sometimes late freezing weather removes fruit for me. Right now, early flowering peaches have fruit about the size of a large pea. A reduced number of flowers, however, usually means poor pruning practices. It’s best to be observant!

Youtube if fruit was killed by a late spring freeze.

            Fruit production varies where you live in the valley and in different microclimates. Some places in the valley (and landscapes) are warmer than other places. At The Orchard at Ahern, we have about 70 varieties of fruit trees producing fruit from late May through December. Our 25 – 30 varieties of peaches finish producing fruit toward the end of July and into the early parts of August. There are varieties that produce peaches in September or October but for me it’s no longer “peach season”. September through December is “apple or pear season”.

            The same holds true for apricots, apples, pears, plums but not citrus. Generally, early flowering fruit trees produce the earliest crops of fruit. These early flowering varieties are also the varieties most likely not to produce fruit because of late spring freezes. If you want to be sure to get early production of fruit, live where it’s less likely to freeze!

            About mid-March I observe the fruit remaining on earliest flowering varieties of peach, plum/pluot, and apricot as indicators for this year’s harvest. Right now, the earliest flowering peaches have fruit that are the size of a large pea. They also have dried up flowers and fruit dropping from the tree because of late spring freezing weather causing them to die.

Summer Pruning Can Be an Important Management Tool

 Summer pruning focuses on removing or robbing the tree of its "invested" new growth. It can help keep tree smaller and reduce the pruning workload in the winter.

Summer pruning would control the size of this tree and reduce the pruning workload during the winter months.

Hedge Needed for Dog Area

Q. I need a hedge to block the dog area from view. Are there any drought tolerant, full sun bushes that can handle extra nitrogen in the soil from the dog urine, or something I can add to the soil to balance that kind of nitrogen? I saw additives that claim to increase the beneficial microbes or bacteria or something like that to help the nitrogen cycle.

A. All plants are damaged if the urine from a dog (male or female) is in contact with any part of the plant. Water to dilute the urine or urea is what is normally recommended. You just have to catch it in time which means following the dog with a hose. 

Roots are the most tender parts of plants

Generally, plant roots are more tender than the stems. Usually leaves of plants are about as tender as the roots. The plant grows back from damaged stems if dog urine is sprayed directly on the leaves or roots. Having soil around the roots makes them less susceptible when in direct contact with dog urine. How much less susceptible depends on the plants. But nearly all leaves are damaged. Stems will grow new leaves when damaged. Roots will grow new roots when damaged.

Differences in Varieties of Texas Rangers

Any of the Texas Rangers will work (aka, Texas Sage). ‘Green Cloud’ or ‘Grey Cloud’ varieties of Texas Rangers get about 10 feet tall and should be planted no closer than 8 feet apart or 8 feet from a solid wall. There are shorter varieties of Texas Rangers, like ‘Compacta’ (5’x5’ and 4 to 5 feet from a solid wall) and ‘Cimmaron’ (3’x3’ and 2 to 3 feet from a solid wall) that use less water because of their size and have a height more appropriate for some sites. They are still Texas Rangers so how often they are irrigated is the same just give them less water each time they are irrigated.

All plants use water. Big plants use more water than little plants. The more plants you have, the more water is needed.

But there are two caveats. Remember ALL plants use water and the more plants of a larger size you have in your landscape, means it can cost more (in water or pumping costs) to irrigate them. The second caveat is that “people schedule when to water plants, plants don’t.” It begs the question, “Are plants responsible for water use or are people?” You can give low water use plants more water than they need, and they won’t care.

Marketing?

Be careful of marketing claims of products. Sometimes they are correct and sometimes they stretch the truth. In your case, I think you are talking about rejuvenating or renewing the soil rather than the plant. Soil renewal is a totally different issue than plant renewal. Protecting the soil won’t protect the plant from urine damage.

Practice Watering and Managing Plants with a Hose and Lopper? Try Jojoba.

Jojoba (Simmondsia californica)

Do you want practice managing a plant that does not need much water by pruning it? Try this Sonoran Desert native plant, Jojoba, and see how you do. I was introduced to this plant in the mid-1980s when it was getting popular as a source of oil. It’s again popular but this time because it doesn’t use much water. Like most desert plants, it responds to watering by growing.

This was a picture of Jojoba taken by Andrea Meckley and posted on my blog in 2014.
https://xtremehorticulture.blogspot.com/2014/09/desert-plants-jojoba.html

You can read more about this plant here in a post by Andrea Meckley I published on this blog in 2014.

Details about Jojoba

Growth of this plant is tied very closely to watering frequency; 1 to 2 inches of water, 3 to 5 times each year. It has the potential for saving water in the landscape if you know how to water and prune it. Most fruit trees require about 50 inches of water each year. This plant grows with 5 to 8 inches of applied water.

If you water it with your controller this is what you are likely to get. This is a jojoba on an irrigation timer.
https://www.public.asu.edu/~camartin/plants/Plant%20html%20files/Irrigated%20jojoba.jpg

·       Unpruned height is nearly 20 feet tall. It grows this tall slowly. Height can be kept 5 to 6 feet tall if pruned once a year or every other year. Don't prune it from the top with a loppers or hedge shears. Get on your hands and knees and prune it with a loppers or hand shears at the base. 

Can it be grown taller and pruned into a small tree? Perhaps. I haven't tried it. Pruning the lower limbs from this giant shrub(above) might make a nice small patio tree.

·       Evergreen plant unless it gets very cold (lower than 20F) and then it drops its leaves and becomes deciduous. At very cold temperatures (below 15F) the top of this plant may die to the ground.

·       Cold temperature limits: 20°F

·       High temperature limits: 125°F +

·       Irrigation: 5 to 8 inches of water each year. Give it 1 to 2 inches of water in the spring, do that twice in the summer months and once in the fall. Apply this water in a basin or donut surrounding the tree to contain the water and reduce water waste. Do not put this plant on an existing irrigation system or you will be sorry because of it’s growth.

·       Planting location: east side of a building or wall is best but tolerates full sun (south or west sides) if planted at least 5 feet from a hot surface. Tolerates planting of rock mulch on the surface of the soil.

·       Spacing from each other or walls: depends on plants mature height. If grown 20 feet in height than planting distance is no closer than 15 feet apart (8 feet from a wall). If pruned to 6 feet height, then plant them no closer than force feet apart (2 feet from a wall).

Male and female plants are wind pollinated much like date palms and corn. If they are propagated by the nursery from seed, then you get 50-50 male and female unless there sexed. If plants are vegetatively propagated (no sex involved) then they will be either all-male or all-female if they came from the same plant. Male plants may cause a pollen problem. Female plants produce the fruit and oil. If these plants are watered too often or the soil has poor drainage, watering frequently on the controller may cause root problems, yellowing and plant death.

Directions for planting Jojoba:

1.     Pick a location for planting, preferably on the east side of your home. The north and south sides are okay as well but the east side is preferred. Pick a spot that is at least half the distance from a wall equal to the height you want it maintained at.

2.     Plant Jojoba (Simmondsia californica) without any drip or supplemental irrigation. It’s okay to put it into a rock landscape. Build a level basin or donut around the plant 4 feet in diameter that can hold 2 inches of water. When watering with a hose, fill this basin or donut only once. Reestablish the irrigation basin when it no longer holds enough water.

3.     Make the hole for it wide and the same depth as the container or roots. The roots of this plant need places to spread horizontally easily.

4.     Stake the plant to establish the roots without wind for one growing season and then remove the stake.

5.     After planting in the spring or fall, wet the soil thoroughly to remove air pockets and establish the roots.

6.     Fertilize this shrub lightly once a year in the spring or fall or when needed.

7.     Manage this plant’s growth by watering its basin.

8.     Prune this plant at its base or bottom. Never prune this plant at its desired height. Prune this plant from your knees. Prune this plant by removing long stems (usually 2-4) near its base (renewal or rejuvenation pruning). Do not prune once a year. Usually not necessary unless it's being watered too often. Every two years, or whenever needed.

Where to get Jojoba?

Check with your local nurseries and see if they haven't first. They usually have some sort of guarantee if it fails. Don't forget to check Lowes or Home Depot as well.

Online nurseries
California online native plant nursery, Las Pilitas

    Arizona online nursery, Desert Horizon Nursery

Listing these online nurseries is not an endorsement of any specific nursery. I don't know them. It's just a suggestion.

Buying and Planting Citrus in the Las Vegas Area

 Buying and planting citrus, subtropical and tropical trees, in the Eastern Mojave Desert can be a challenge. First is finding a good location then amending the soil, staking the tree and watering it. Learn how it is best done in this episode of Desert Horticulture. 

Citrus selection can be tricky in the Las Vegas area due to our winter cold temperatures. Citrus with a think rind can indicate a potassium deficiency. Always use a citrus fertilizer once a year in the spring.

Why 'Improved Meyer' Lemon instead of 'Eureka' Lemon in St. George Utah

Q. I am writing regarding the purchase and planting of a ‘Eureka’ lemon tree. Of main concern to me is where to plant the tree, where to purchase the tree, what sized tree should I purchase, how often should it be watered and fertilized, and how big should I make the planting hole?

Meyer lemon tree growing in a container in Las Vegas.

A. a ‘Eureka’ lemon is not a preferred lemon for our area due to its low tolerance of our colder winter temperatures. Meyer lemon begins its cold winter damage at about 25F or a bit less, but ‘Eureka’ lemon starts getting damage at freezing (32F). That’s a 7°F difference in cold tolerance not even considering wind damage! ‘Meyer Lemon’ is not a true lemon like ‘Eureka’, but the flavor is very close.

Eureka lemon in Las Vegas

            If freezing weather threatens, wheel the tree and container into the garage until the freezing temperature is over then wheel it back out. You can try covering it with a frost blanket. This gives the tree about 5°F of added protection (to about 27°F depending on the wind). You can try Christmas tree lights that radiate heat (it may help a few degrees) but again it depends on the wind.

Large unknown lemon grown in Lake Havasu, AZ.

            The rest of the information you asked about is the same regardless of the variety. Depending on which variety you want, you may have to purchase it from an online nursery. Select an average sized tree, about 5 gallons in size, and plant it in the warmest microclimate you can find surrounding your house (usually it’s on the south or west side). Amend the soil with compost at planting time and dig the planting hole three times the width of the roots. Plant it 8 to 5 feet from a warm wall and protect it from the wind. Stake it for at least one year if it is a 5-gallon size or larger. Plant wet. Cover the soil with woodchips when finished. Protect it from rabbits.

Controlling the Wind Is an Important Part of Desert Horticulture

In this episode of Desert Horticulture learn that visual and nonvisual types of damage that occur to landscape plants, (vegetables, fruit and ornamentals) and how to control it.

Wet the Soil First Before Digging the Planting Hole

Q. I'm finally having my empty backyard landscaped. It's the typical subdivision super hard "soil". Should it be amended somehow before the new plants are added? More than just in the hole where the plant goes, I mean.

Wet the soil first a few days before digging. Moist soil helps to make it softer. Mix compost with the soil taken from the hole by about 25 to 33%.

A. Some of the landscape soils are hard, hard, hard! Wet the area to be planted with an hour of sprinkler water from a hose and sprinkler a few days before digging. This water will help make it softer to dig. I would recommend amending the soil in the planting hole with compost or another amendment a few days after it is wetted. Amend it between 25 to 33% with compost (one shovelful of compost to 3 or 4 shovelfuls of soil). The hole for the plant should be dug and amended to a width three times the size of the diameter of the container or roots. Then check it for drainage. The hole should drain water overnight. Wet amended soil should be at least chocolate brown in color.

Holes located where fruit trees are to be grown are wetted and amended with compost by about 25 to 33%.

            The hole does not have to be dug deeper than the container but should be dug three times the root width of the plants. Amend that soil taken from the hole. The only time the soil needs to be dug deeper than the container is when the soil is very bad at draining water. If a planting hole is filled with water and it drains this water overnight, then the drainage is good enough; three times the width of the roots/container is enough soil preparation.

Younger trees are planted in wet, amended soil, covered in woodchips and staked to prevent them from blowing over in strong winds.

            If the water does not drain from the hole overnight, you should plant on top of an embankment or a small hill. If you are planting a medium sized shrub (6 to 10 feet tall) in this spot, then the soil in the amended mound or hill should be 12 inches tall and about three or four feet wide. If the tree or shrub is 20 feet tall then the soil mound should be 18 inches high. Cover this soil with a mulch of some sort, either woodchips or rock depending on the type of plant.

Wind is Damaging to Plants

Windy Weather

Windy weather, like we had over a past weekend, is very damaging to plants. (Notice I said “is” and not “can be”?) Light winds cause very little damage. Moderate winds cause moderate amounts of damage. Strong winds cause lots of damage. Why? I can think of at least two reasons; extent of damage and water use.

Shallow rooting of tree because of annual flowers planted at its base.

Vegetables and Wind

            Vegetables grow the best when located closest to the downwind side of a windbreak. Plants don’t care if the windbreak is living or not, they just want the wind slowed. For this reason, the best windbreaks are not solid walls (e.g., block walls) but perforated walls (e.g., chain-link fence with slats inserted in them). Solid walls cause the wind to swirl. Perforated walls cause the wind to slow. Science has shown us the best windbreaks are about 80-90% solid, not 100% solid.

Windbreaks for orchard in a canyon

Wind Damage and Fruit Trees

            Examples of damage include leaf and flower damage with small fruit ripped from the tree with some types of fruit trees. Plants grown in windy spots are smaller than plants grown in protected areas. In strong windy locations I have seen fruit trees that lean away from the wind. Wind damage to fruit trees is the worst on trees closest to the wind. Wind damage lessens on the second and third row of fruit trees. Plant fruit trees in blocks so they give each other wind protection. Locate fruit trees that tolerate wind damage the most on the windward side of the block. Examples of wind tolerant fruit trees are pomegranates, apples, and pears. These trees will protect the less wind tolerant fruit trees. Fruit trees less tolerant of wind include citrus, plums, apricots, and peaches.

Wind and Water Use

            Plants during windy weather use more water. If the winds are strong and continuous, they use more water! Wind is a strong predictor of plant water use. In fact, along with how bright the sun is shining it is one of the strongest predictors of plant water use. 

Pay Attention

Go outside in the morning. Look at the weather. Is it bright and sunny with very few clouds in the sky? Winds is a major predictor of high-water use. Look at the trees. Are the leaves moving? Look at a flag flying on a flagpole. Is the flag barely moving? Is the flag flapping a lot? Is the flag rippling because of the wind? Those are indicators of wind strength. Bright, cloudless skies and strong winds equals high water use in our desert climate. It’s time to water during bright windy weather.

Will a Caper Bush Grow in Las Vegas?

Q. Will a caper bush (Capparis spinosa) grow in Las Vegas? Where might I buy one? I called a local nursery and got nowhere.

A. Briny capers are the unripened flower buds from a wild spiny plant that grows in the Mediterranean region and parts of Asia. Immature flowers from these plants are dried and then put in a brine solution for preservation. Their lemony, floral hints might remind you slightly of green olives since they are added to food as a condiment.

More on Capers from Wikipedia

            The plants are usually started from seed but I’m sure some entrepreneurial online nursery grows them as plants to sell. They are about 3 feet tall and wider than they are tall since the stems tend to lay down if given a lot of water. 

I have never tried to grow them in our climate. They have enough cold tolerance and they are Mediterranean. I would try it on the Eastern side of a building with soil improvement and additional water at the time of planting. I’m no expert but if this plant grows in the dry, hot Mediterranean region, it has a good chance of surviving our desert climate as well.  The information I saw maintains they are good down to winter temperatures of about 20°F when they get older and larger. If temperatures get in the low 20s this plant suckers from its base. Think Bay Laurel, oleander, Italian Cypress, and you’ll get an idea of the climate and soils they like.

Finely Ground Eggshells are Okay for Desert Garden Soils

Q. I read somewhere that putting crushed up eggshells is good for the garden, so I have been doing that. I also throw tea leaves and coffee grounds on the garden which I know is good, but I was wondering about the eggshells. Are they helpful and I should continue or forget it and throw them out?

Eggs and bananas at our farm in Batangas, Philippines. Ground up eggshells are better chemically for the soil in out tropical, high rainfall soil than in the desert where there is plenty of calcium. Banana peels release more nutrients than the eggshells. 

A. They do two things; organics improve the structure and texture of the soil and add to its chemistry. Warm wet soil decomposes the smallest stuff first. Put eggshells and tea leaves in a blender with some water before composting or adding them to a soil. Coffee grounds are already “ground up” so it’s not necessary to use a blender. 

Any kind of “organic” breaks down in the soil through the action of organisms where it turns into “Black Gold”, improving soil structure and slowly releasing the chemicals they contain. There is a lot of information available on the chemicals released by eggshells, tea leaves and coffee grounds. But get them small if you want them to be released quicker. When adding stuff to the soil it is better to add a whole bunch of different stuff than just one thing like all eggshells or all banana peels.

Eggshells are mostly calcium, the same kind used to increase alkalinity in soil  It is better for soils that are more acidic such as higher rainfall areas. But still eggshells are not bad for the soil. 

Garage of Old Fertilizers - What to Do?

Q. What do I do with all the partially used chemical fertilizers in my garage?

Chemical storage.

A. Most mineral fertilizers can be applied as the fertilizer bag recommends. They dont go bad unless they get wet. 

Some fertilizers that contain pesticides must be disposed of properly. If your fertilizer does contain a pesticide then ask me how to get rid of it. If permitted and you no longer want or need these types of fertilizers, give them to your non-organic neighbors for application. It’s best to use them up as normal applications rather than put them out as garbage.

            The mineral fertilizers considered “hazardous waste” usually have a weed killer or insecticide that is no longer permitted to be applied by homeowners. These fertilizers should be considered hazardous waste and disposed of according to county regulations that are intended to protect our water supply. Other types of mineral fertilizers can legally be applied. But ask to make sure.