Bitter Orange a Good Choice for Las Vegas But....

Q. Is it possible to grow sour or bitter orange in Vegas? It’s becoming almost impossible to find at the local markets and we use it in so many recipes. I was curious if that was something that might grow here? When should I plant it?

Bitter orange, sometimes called trifoliate orange, is a good choice for colder climates like Las Vegas where it oftentimes freezes.

A. They aren’t very popular here. I understand why you might want to grow them. We are talking about Citrus aurentium. They are used as a landscape highway plant or landscape hedge in the Phoenix area where it’s warmer during the winter. Here they are mostly used as a low temperature rootstock for citrus when shipped to our area by wholesale nurseries. Trifoliate orange is used primarily as a freeze tolerant rootstock for our area, but sour orange is also used.

Sour orange is used as a rootstock for citrus needing to be cold hardy. If the top of a citrus dies due to freezing temperatures, at least the rootstock will sprout and grow after the top freezes.

I don't have the information on their low temperature tolerance for the winter, but I think it’s around 20° F so it would be a good choice for planting in the Las Vegas area. Meyer lemon and kumquat, two more commonly grown citrus here, will handle freezing temperatures to about 24-25° F. once established. In protected backyards Meyer lemon, grapefruit, and kumquat survive most of our winters. So, my guess a fifteen-foot sour orange will be at least reach those temperatures, if not a bit lower.

This tree should start flowering in about year four to six. You will still lose fruit due to early spring freezes combined with open flowers in some landscapes depending on its exposure to early spring freezes and wind. But the tree itself should survive our annual fluctuating freezing temperatures for about 25 years or more.

Remember ALL citrus are from China and parts of southeast Asia. This means the desert soil needs to be amended at the time of planting, and periodically adding amendments to the soil. No citrus are xeric so they will need about the same amount of water as regular fruit trees of a similar size, about 4 to five feet of water under applied under its canopy in one year.

Just for your information bitter orange does get a deadly disease occasionally but it's usually not prevalent in non-orchard citrus areas so you should be all right. Buy the tree smaller and protect the tree from sun damage through shading itself or providing it shade while it gets established. Buy a tree that is shrublike.

You won’t find it locally. It is not that popular as a tree on its own. I think you will have to order it online. Places outside of the desert southwest don’t have to worry much about sun damage to the trunk so it is limbed up higher into a tree. For this reason, you want to buy it grown into as much of a bush as possible. Limb it up later when it gets older and acclimated to our desert. The best places to order it are from Arizona nurseries such as Whitfill or Greenfield if they will ship it to you. Both are in the Phoenix area.

Plant it when temperatures are cool, but spring planting is best in the case of citrus. Because of digging and availability, most nurseries sell bareroot trees in the spring. Bareroot trees need to be planted as early in the spring as possible. Potted or container trees can be bought anytime but planting them is always best in the spring. If it were totally freeze tolerant, or you were sure it will not get extremely cold this winter and you can find it available, then fall planting is always best.

Branch Dieback in Citrus (Orange)

Q. I have a ‘Eureka’ lemon tree with a branch or two that are dying. Is this borers?

Lemon tree with single branch dying back.

A. Probably not borers but a disease. Look for sap near the location where the branch died.

Single Branch Dieback of Lemon Most Likely Shoot and Twig Dieback Disease

Branch dieback in citrus, particularly lemon, is very confusing. It is not likely to be a borer problem. Most likely it is a disease issue called “shoot and twig dieback” of citrus. A lot of federal funding went to California to answer a branch dieback disease questions for homeowners and commercial growers, with lemon branch dieback found to be quite common.

            If it were me, I would cut the dead branches back and eliminate the dead branch to a place where it was healthy and growing in the direction I wanted. As a precaution, I would sanitize the pruning shears with undiluted 70-90% ethyl alcohol before and after each branch removal. Treat the fresh cuts with copper sulfate (Bordeaux mix) as a precaution.

Citrus in Las Vegas Nevada

            

 I was accused of not wanting citrus in our area. That isn’t true. Nothing wrong with growing citrus here. But I want you to be aware of its problems when citrus is grown here and adjust your expectations accordingly. This is the Mojave Desert. Las Vegas and the high or middle deserts can have cold winters, unexpected early spring frosts and winds. It can survive cold temperatures ranging from the mid to low 20’s all the way to no freeze at all depending on the type of citrus.

Sour orange rootstock grows from the base of this orange tree because the top died when it froze leaving the rootstock to grow and produce fruit that has dropped on the ground.

            Early spring light frosts can be a problem for all fruit trees including citrus. All it takes is a few minutes of freezing temperatures just before sunrise. If flowers are open or close to opening, part or all your fruit is dead. The fruit or flowers drop from the trees a week or two later even though bees were plentiful.

Many citrus are subtropical

Citrus originates from different parts of Asia. This means they prefer growing in soils that have some organics in them. Desert soils don’t have any or very little. When soils are covered in rock, the soil organics are fine right after planting and these organics can last last several years. After several years, the soil “organics” used at planting time are depleted and must be replenished. This can be done by raking the rocks back, applying fine wood chips to the soil, and raking the rock back or applying these same amendments over large rock and watering it in.

Citrus can yellow and eventually dieback if the soil is not improved when it grows in rock.

Citrus can also yellow when grown with woodchips if the woodchips are not thick enough or if planted and watered incorrectly. Most yellow leaves can be turned green again if an iron chelate (I would recommend iron eddha for the chelated iron) is applied to the soil in early spring.

            When purchasing citrus be aware that these are fruit trees that are “iffy” when grown here. Sometimes they work and sometimes they don’t. Adjust your expectations accordingly.

Pruning Navel Orange Tree

 Q. Do you have any recommendations for pruning our poorly maintained ‘Navel’ orange tree?  The main trunk has grown to about 34” from the ground and leafed and branched out.  Last season a “sucker” shoot sprouted from the side of the truck and wasn’t pruned out.  Now it exceeds 8’ but seems extremely happy. 

Get rid of that sucker from the rootstock!

A. That sucker is part of the rootstock and not part of the tree. You don’t want it to stay. It should be removed when you first saw it. See how the leaves growing on it are different looking from the Mother plant? Not only that, the growth from it was so rapid the crotch makes a narrow letter “V”. It will not support the weight of itself, plus its fruit, as the tree gets bigger.

Narrow crotches can support much weight. They make the letter "V" and good crotches make the letter "U".

This type of branch will split from the tree. Not only that, this unwanted growth “robs” the rest of the tree from “food” that it makes as it gets larger and denser. What wasted growth! Remove this sucker now and don’t leave a stub attached to the trunk when you do. It should have been removed when it was first seen. Remember, if growth is a size that hand pruners can remove, then do it anytime!

Early Freezing Weather Makes Fruit Drop Early

            The most likely reason your fruit has fallen from the tree was because of early winter and spring freezes. The flowers froze, unpollinated, the fruit then died and fell off. This result can change from year to year depending on early spring freezing temperatures.

Citrus in General Not a Good Choice for Freezing Climates

            Keep in mind this is a ‘Navel’ orange and not the best choice for our Las Vegas climate. A better choice would be a ‘Satsuma’ orange (tangerine) because of our cold winters. The tree can still lose fruit due to early spring freezing temperatures but at least you won’t lose the whole tree! However, placement in the right microclimate for either orange type, ‘Navel’ or ‘Satsuma’, may make a difference.

For ‘Navel’ orange place it in the warmer microclimate of your landscape such as a south or west side. It needs protection from winter cold to survive. The more cold tolerant ‘Satsuma’ would be placed in a colder microclimate, such as the north or east side, of the landscape. This placement delays the flowering of this tree as long as possible. Your choice with which you want to keep but my vote is for changing to a Satsuma.

Calamondin, or Calamansi, Tender to Winter Temperatures in Las Vegas

 Q. I received a young calamondin tree from a friend in memory of my father’s passing. I would love to nurture and grow this tree successfully. Any tips? Is it likely to bear fruit? How long should a small nursery stake remain?

To start side branching and protecting its trunk from the intense desert sunlight, this tree should be pruned at about knee height. During the next three years, leave it alone.

A. I am sorry for your loss. In the Philippines, where it is a native, it is called calamansi in Filipino or Tagalog. So therefore, it is subtropical, and it will not tolerate freezing temperatures, much below about 28F. If we get a cold winter, it can freeze.

It does not like our desert, so it prefers locations on the north or east side of your home. And lastly, it likes amended soil so plant it either with compost mixed in the soil (one shovelful for each three of desert soil). It grows best in soils covered in wood chips. However, if your soil is covered in rock, then rake back the rock and apply about a quarter of an inch of compost and water it in. Do this every other year.

Never plant in a dry hole. The soil in the planting hole is wet and filled with amended soil. 

When staking fruit trees they don't need a large tree stake unless they are huge. Use the stake that came in the container. After planting, push it deeper and tie the tree to the nursery stake with stretchable nursery tape. Remove after the tree is growing well, usually the next year.

             When planting it, pound the stake into the solid ground beneath the planting hole so that it supports the tree. Then tie the tree tight to the stake with green nursery tape. Remove the planting stake and tape after one growing season. When it gets established but still young, form a small tree by pruning it at knee height. Remove any limbs that are growing along the trunk below this cut.

Don't expect this kind of crop on your tree. This is exceptional and can result from planting in the right climate, providing fertilizer and water when it needs it. 

The fruit is about the size of a large marble or small golf ball and the juice and pulp is tart, like a lime. The tree should start bearing fruit when it is still small and young, perhaps the second year after it is planted. The production of fruit will become more as it gets bigger. It is harvested when the green color of the rind starts to turn from green to light green. Filipinos use it for flavoring fish (by squeezing a cut fruit seeds and all) and also as a beverage like a lime and many other things. 

Orange Tree Problems During and Shortly After Rain

Q. What is wrong with my orange tree? It has lots of oranges, but the tips of the trees are dying in some places.

Any plants, including this citrus, can have problems after a rain in the desert. 

A. Your pictures look like either an insect or disease problem, both I have few skills about. First, I would open the canopy of the tree a bit more by reaching inside of it and pruning the limbs at a joint (where they come together) and remove one of them to make the canopy of the tree more open. That will help air circulation a critical factor for disease control. In some cases, it can remove disease problems when humidity and air movement are factors.

Secondly, after the canopy is more open, I would look at the damaged areas. If you bend the branches that remain you can determine if it is an insect or disease problem. The insects will weaken the branches just below the damaged areas and break. Diseases will not unless the area is dead. Look for insect damage or disease problems just below the dead or dying areas.

Sorry, but there may not be any chemicals of use. Just plant management or wait for a change in the weather.

Homeowner Forced to Water With a Hose

Q. I have emailed you before about having only one watering zone. Our lemon tree seems to be doing worse every year. With only one irrigation zone unfortunately I am forced to water every day in the summer.  We decided we should water these citrus trees by hand. So, we have two questions please: How much water per watering and how often?

Homeowner Forced to Water with a Hose

A. Looks like fake grass was installed surrounding the tree. It is too perfect. This may be a problem in future years due to numerous soil problems, primarily air reaching the tree roots and compaction from people walking near it. Pull the fake grass away from the tree to the size of the canopy. It is important that plant roots breathe air. Some types of fake grass are better at that than others. Make sure enough air is getting to plant roots.

How To Hand Water Citrus

 Start watering this tree now with about fifteen gallons each time (judging its size from your picture). As the tree increases in size it needs more water; probably about every three or four years the area under the tree canopy will need to become bigger to give it this. The tree will max out at about thirty gallons each time it is watered. When an increase in water is needed, remove more grass, to accommodate the amount of water applied. The easiest way to give the tree more water and keep it from falling over will be to increase the size of the area where water is applied to at least half the area of the canopy.

Use Moat or Donut

This is a basin at the bottom of a fruit tree in North Las Vegas. Both basin and bubbler..which this is..and drip irrigation are both efficient at this.

Use a moat or donut shaped basin around the tree for filling each time with a hose. The basin, and the inside being flat, will hold water long enough to get it deeper in the soil. If the tree does not have a moat or donut around it, it is difficult to put enough water in that spot to wet the soil eighteen inches deep each time. Just putting a hose on it will not work unless you water with a sprinkler or let the hose run slow a long time. Using a moat or donut will fill the basin with water in about ten minutes or less and keep it contained.

Correcting Lemon Mistakes Through Proper Pruning When Young

Q. Your Xtremehorticulture blog is an awesome source of information! I live in Phoenix and question why my ‘Lisbon’ lemon tree is failing after two years. It flowers in the early spring as it should, and produces fruit, albeit, its fruit is nasty and dry. The canopy is about 10% of what it should be, and I suspect sunburn has been choking the plant. I think the tree is a goner and thinking of removing it.

'Lisbon' lemon tree grown in Las Vegas and sun damage to the leaves.

A. Yes, I think your tree may be sunburned. Give it a chance still. At two years of age, you might be able to nurse it back to health if you follow some easy directions.

You live in the northern part of the Sonoran Desert. Las Vegas is in the eastern side of the Mojave Desert. All citrus including ‘Lisbon’ lemon are subtropical; this means the tree, unlike ‘Myers’ lemon, doesn’t survive freezing temperatures very long. And in your case our very strong desert sunlight. As the canopy increases in shade and size, giving more shade to the fruit and the tree itself, the fruit will improve. Guaranteed. Don’t let the fruit overripen before you pick it. That’s a no-no.

This citrus tree was limbed up too soon and the trunk may develop sunburn in hot locations.

You might be able to get away “limbing it up” like in the seaside and Mediterranean area of Portugal, where ‘Lisbon’ lemon probably originated, but it won’t work in the desert Southwest. Leave the tree shrub-like the first few years until it gets established and then slowly limb it up, making sure the trunk and limbs stay shaded, as it gets older.

Citrus with a full canopy but exposed fruit still developed sunburn in Arizona.

Make sure the soil has been amended at the time of planting. This is a subtropical fruit tree and requires more organic matter in the soil than we have in most of our desert soils. I would not surround this tree with rock or rock mulch on the surface of the soil. Instead, use a layer of 3 to 4 inches of wood chips keeping the wood chips away from the trunk the first few years of its life. As the wood chips on the soil surface decompose or rot in the presence of water, it will slowly add “organics” back to the soil. Rock doesn’t do that.

The last thing to consider is planting the tree on the north or east side of your landscape, or at least 3 or 4 feet away from a hot west facing or South facing wall. It may or may not need it but it can help the tree. All fruit trees need about eight hours of sunlight each day, but subtropical trees can do without the 120°F heat common in Phoenix. If they are in good health, they will withstand the desert heat.

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.

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.

Leaves Yellowing on Calamondin Citrus Tree

Q. What causes leaves to yellow and black spots to develop on leaves of my calamondin citrus tree? I had them for seven years and they just now developed these yellow leaves with black spots. Nursery information desk advised picking off all affected leaves (but there are too, too many) then spray with cooper fungicide.

A. Combined with leaf yellowing, it sounds like either a nutrient or watering problem or both, not a disease problem. Copper sprays like Bordeaux Sprays, are usually recommended for disease control but I don't think that is it.

This is photinia but you get the leaf yellow idea from this pisture.

Try this:

    1. Cover the soil with 1/4 inch of rich compost or compost plus some fertilizer high in nitrogen

    2. Then cover the compost or compost/fertilizer with woodchips

    3. Apply a citrus fertilizer in January

    4. Try adding an iron fertilizer (I suggest an iron chelate called 133 or iron EDDHA)

This is the most effective iron treatment (EDDHA chelate) but it is more expensive than other iron chelates. Apply it in the spring (February) or no later t
han early summer (April/May) for best results.

If these citrus trees are in rock mulch, then it's a nutrient and drainage problem. Auger four or five holes into the ground, 2 feet deep and 1 to 2 feet from the trunk, to improve drainage. Fill these holes with soil mixed 50/50 with compost and an iron fertilizer.

Citrus fertilizers contain plant nutrients in higher concentrations than other plant nutrients particularly when these fertilizers are formulated for the desert Southwest like Arizona's Best and Grow Well brands.

            

Mix iron chelate with the compost before using it to fill the augured holes. Water once a week through the augured holes, filling them with a hose. Also, try spraying the leaves with an iron chelate solution four or five times, a few days apart. If this is an iron problem, even though it’s caused by poor drainage, the leaves should begin to get darker in color.

Put about four of these holes about 18 to 24 inches from the tree trunk  and 2 to 3 feet deep to improve drainage. If they are filled with gravel or woodchips they will stay open. They act as drainage sumps (French drains) around trees (vertical mulching).

Nutrient problems can be caused by poor drainage. That's why I'm giving a recommendation to improve the drainage using vertically augured holes and combining it with a compost and iron application at the same time.

Sap Is Oozing from My Kumquat Limbs

Q. Unfortunately it appears our kumquat trees may have bacterial blast fungus. Our tree appears very healthy and has given us a lot of fruit, but we recently noticed sap coming from the bottom of main branches. What treatment would you recommend?

Sam is oozing from the limbs of this kumquat.It sounds crazy but disease stress from management issues can cause sap oozing like this to appear. The KISS rule tells me to look at the soil and watering issues first.

A. I usually follow the KISS rules for diagnosing plant problems. Unless we are in a citrus production area, or there is a history of disease on these trees, I first conclude it's a man-made problem. Regardless, we must rule out the simplest reasons first before we jump to more exotic disease problems.

            Root death because soils are kept too wet cause these symptoms on citrus. For this reason, I assume the trees watered too often or there is a water drainage problem in the soil surrounding the roots.

Simple test if watering too often issues

After the first year of growth, all fruit trees, including citrus, should be rooted firmly in the soil. A simple diagnostic tool helps judge whether wet soils should be a concern or not. Move the tree by its trunk, back and forth, while looking at where the tree enters the soil. The tree should be firmly anchored in the soil and not move it. If tree roots move the soil easily, then the soil has probably been kept too wet and the roots began “drowning” or rotting. 

            There is a tendency during hot weather to water fruit trees more often, even daily. Most fruit trees, including citrus, prefer at least one day of no watering between watering days. Unless the tree is newly planted, or planted in sand, never water trees daily. Instead, increase the minutes on the clock when you do water.

Mulch can add one extra day between irrigations

            Anything that shades the surface of the soil during summer helps tree roots function better. Their primary functions regarding tree health are the uptake of minerals and water. They do this better, however, if the surface of the soil is mulched. Woodchips (or even shredded cardboard, shredded newspaper or straw) lying on the soil surface gives fruit trees one extra day between waterings during the summer.

            If the soil is not mulched or covered, soils dry quickly and get hot in our summer sun and heat. When soils are wet, tree roots grow where there is a good mix of air and water. Unless the soil has been amended quite a distance from the tree at the time of planting, most of the tiny roots that feed on water and nutrients grow in the top 6 inches of soil.

Tangerine Leaves Curling

Q. Please help me to recover my tangerine tree leaves curling inwards. Most have very small black spots on them. l observed the leaves and don`t see any insects. l do deep hose watering during hot summer days.

Picture of tangerine leaves curling and dropping

A. There are lots of reasons for citrus leaves curling. This problem is near legendary for citrus leaves but the reason is usually environmental and not from insects or disease. I’m not saying it can’t happen but it’s less likely.

Citrus troubleshooting guide Arizona

Cold weather

            Since this question was sent to me at the end of winter, cold weather comes to mind. Cold temperatures can cause leaves to roll. Some say cold weather can cause leaf spotting as well. If leaf rolling was during the summer, guess what? High temperatures can also cause citrus leaves to roll.

Watering

            Moisture stress can cause leaf roll and leaf drop. When timing irrigations, make sure the soil is no longer wet when the irrigation water is applied. In the same token, make sure the soil does not get too dry between irrigations. Dry and wet soils can cause leaf rolling.

            What’s more important, in my opinion, is overall tree health. Plants in poor health are more susceptible to problems than those that are healthy.

Soil problems

            In the picture you sent, I noticed the condition of the soil surrounding these trees. The soil looked pretty bad, even by Las Vegas standards. Poor soil conditions leads to poor plant health in the future.

            Good soil health begins at the time of planting. I realize your tree has already been planted but soil improvement surrounding the roots at the time of planting is a huge future investment in plant health for years to come. In the future, excavate the planting hole 3 to 4 feet in diameter and 18 inches deep at the center. Mix good compost with your excavated soil at a rate of about 1:1; for every shovelful of soil, mix one shovelful of compost.

What to do?

            What can you do now? Put a half bag of compost on the soil surrounding the tree. On top of this, put a 4 to 6 inch layer of woodchips and water it in. Woodchips, where irrigation water is present, improves the soil health where most of the feeder roots of your tree are living.

Spreading good quality compost at the base of trees for its fertilizer content

            Improving the soil improves water, fertilizer and nutrient uptake by these roots which in turn improves the overall health of the tree. Soil improvement using this method helps remove some irrigation problems that could be causing leaf rolling. Overall, this means fewer problems for your citrus in the future.

Community mulch pile at the University Orchard North Las Vegas

            Get these woodchips free by visiting Cooperative Extension locations south of the airport or in North Las Vegas at the University Orchard in the Aliante community. For more information about these free woodchips call the extension hotline at 702 – 257 – 5555.

Lemon Not Meyers, Remove Fruit?

Q. My lemon is not a Meyers lemon but the tree is starting to flower. I didn’t want to pick them this early because they are still getting sweeter. Does the "remove lemons before the tree flowers" rule apply to this variety as well? 

Ponderosa lemon ready to pick on the left and immature on the right. On the tree at the same time.

Rough lemon grown in Las Vegas

A. Yes it does. It applies to all fruit trees. Try thinking like a lemon tree. The reason the tree produces fruit is to reproduce. When the fruit drops to the ground, the fruit rots and releases nutrients that feed developing seedlings.

            The tree “knows” if there is fruit attached to its branches or not. It can’t see anything but there are other types of communication that trees have perfected. When the fruit has been picked, the tree “knows” the fruit is no longer there.

            The reason for picking fruit before the tree begins flowering is to send “signals” back to the tree that it no longer has fruit attached to its branches. When fruit is missing, the reproductive or flowering cycle of the tree is encouraged.

            The beginning of flowering is the beginning of the reproductive cycle. The normal flowering cycle of trees is at certain times of the year. If this time for the normal flowering cycle to begin has passed or is delayed, the tree may not flower at all or flower very lightly.

Lemon turning yellow but hasn't quite got there yet. The color change can happen faster in the presence of ethylene gas. Ripening bananas give off lots of ethylene gas and can be used to improve coloration of citrus.

            You are right. Most citrus are considered non-climacteric, or, in other words the fruit doesn’t increase in sweetness after it is picked. It is best to wait when picking lemons to improve its sweetness, but you don’t want to leave it on the tree long enough to interfere with flowering.

            Other fruit which don’t ripen or ripen little after picking include figs, grapes, pomegranates, cherries and apples. As a consumer this means the sweetness of non-climacteric fruit does not increase much, if at all, after picking.

           If citrus is left too long on the tree fruit quality is reduced because it becomes “pithy”; it starts drying out. Remove all fruit from trees before they begin their next flowering cycle.

Damage to Citrus Leaves Varies with Seasons

Q. Someone I know is having problems with something eating the leaves on his citrus tree.  I cannot think of what animal would do this.  Can you?

Feeding damage by insects can vary with the maturity of the leaf

A.  If this damage occurred to citrus leaves earlier in the season when temperatures were warm, it could because the by insects or even snails. If this is happening now, while temperatures are cold, then think of warm blooded animals such as rabbits, ground squirrels or even rats.

Ground squirrels hibernate when temperatures are cold but you may see them active when temperatures are still warm but it is winter time.

Citrus leaves will probably drop when the temperatures get cold enough and so that problem will be gone. I would not worry about it too much at this time of the year. It would be more of a problem if leaves started disappearing during warm weather when the plant is relying on the sun for its source of energy. If it's caused by warm-blooded animals, they will move on to something else.

Fertilizers: Pay for Convenience or Do-It-Yourself?

Q. What are the year-long fertilizer requirements for landscape plants ranging from acid loving to desert lovers such as cacti, palms and other plants to beautify home landscapes.

 

Many cactus lovers swear byproducts such as cactus juice but most cacti do quite well with a variety of different types of fertilizers

A. Desert gardening and horticulture is more difficult to practice than traditional horticulture talked about on most blogs, information sheets, YouTube videos, books and other places. Most information in the media is derived from “traditional horticulture” and these practices may or may not work in the desert.

This powdered fertilizer meant for dry or liquid applications has combined fertilizers that create more acidity than some other types. But it has other fertilizers in it as well good for acid loving plants.

            When applying fertilizers to landscapes in desert climates and soils, consider soil improvement and irrigation beforehand. Soil improvement, where and when needed, solves many fertilizer issues.

A good citrus fertilizer that can be mimicked by combining other fertilizers less expensive. But it's convenience and knowledge that make the sale for most homeowners.

            The biggest mistake made by desert horticulturists and gardeners is a lack of soil improvement to desert soils when and where needed. Desert soil improvement solves 90% of the fertilizer and irrigation issues in residential landscapes. Because the majority of plants grown in desert landscapes are NOT desert plants.

Compost is a great all around fertilizer for most plants. It contains dozens of different minerals and elements not found in commercial fertilizers. Besides that, good compost is biologically active and help stimulate microorganisms better than commercial fertilizers.

            Spend more money and effort on improving the soil than buying and applying specialty fertilizers. Improving the soil and using organic surface mulches around non-desert plants reduces the need for chemical soil amendments, fertilizer applications and pesticides.

Called a starter fertilizer because it is high in phosphorus, the middle number. Excellent fertilizer when planting for the first time or seeding in the garden. You can mimic this fertilizer and save a little bit of money but is it worth it?

            With proper soil improvement, here are my recommendations for fertilizer applications, either conventional or organic:

·        nitrogen and potassium is needed by all plants on a regular basis

·        apply phosphorous fertilizers when planting: seed, transplants from containers or bare root, rhizomes, bulbs or any plant just getting started

·        plants grown for their flowers or fruit require at least one fertilizer application of nitrogen plus phosphorus during the growing season and applied 2 weeks before flowering and fruiting

·        fertilize vegetables and annual flowers monthly; lawns every 8 weeks

·        fertilize prized landscape plants more often than “ordinary” landscape plants

·        use specialty fertilizers on rare occasions for very specific reasons