Xtremehorticulture

Yellow Leaves on Potted Myer Lemon

Q.  I have a Myers lemon tree in a pot on a south facing patio. The wall near it faces east and there was a large pine tree out front so it receives shade in the afternoon. There are quite a few yellow leaves that just appeared. All the new fruit has turned black. It seems to me that maybe I just need to replace this tree. The lime tree is doing very well in a similar location. A. The picture you sent to me shows a Myer lemon with ready to harvest fruit being grown in a small container with smaller plants growing around its base. Meyer lemon typically flowers sometime in January and February. The fruit can be harvested starting about now (December) with this harvest, finished by January, encourages new flower development for next year’s production. Producing flowers and then fruit in midfall is early for Meyer lemon. Early flower development can be a sign that it is under some sort of stress. Certainly it’s not normal for this type of tree at this time of year.             All fruit trees and vegetables need a minimum of six hours of full direct sunlight. 8 hours is even better. In home landscapes the best sunlight for it in our hot climate in the summer months is during the cooler morning hours. Partial shade may be pleasant for people sitting on the patio but not for many plants that produce fruit or vegetables. If shade is present during most sunlight hours, then I would recommend an ornamental plant for that spot with variegated or colorful leaves, not a flowering or a fruit-producing plant. A non-flowering ornamental handles shade better than a flowering plant, whether those flowers produce fruit or not. Don’t Plant Annuals at the Base of Perennial Trees             Secondly, and perhaps more importantly, are the smaller plants demand for frequent watering compared to the tree. Growing a shallow-rooted plant or plants at the base of a deeper-rooted plant is a big “no-no” regarding how often water is applied. Shallow-rooted plants “signal” they need water applied more often than deeper-rooted plants, so they get water applied more often than the watering frequency needed for deeper-rooted plant needs. This type of watering can suffocate the roots of a deeper-rooted plant. Watering a deeper-rooted plant too often can produce leaf drop, flower drop, fruit blackening, and a tree that’s “loose in the soil”. Trees that develop “collar rot disease need to be staked after just a few years of growth. Does that sound like your fruit tree?             I would replace this tree with a plant that requires moderate to low levels of sunlight. If you want to grow other plants along with it, select plants with a similar rooting depth and need for applied water.

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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.

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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.

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Why Does My Orange Tree Have No Fruit?

Q. I have a dwarf orange tree planted a little over a year ago. There have been no oranges on the tree. I have fertilized and I think I’ve been watering it correctly. The tree appears to be healthy just no fruit. Any suggestions? A. Dwarf orange is not much help to me. The subject of oranges is huge. I need to know what type of orange it is, whether it has produced flowers or not and no fruit, or no flowers and no fruit. Varieties vary from early ripening – about 8 months from bloom – to late – up to 16 months from bloom. There are three main groups: The normal fruited, without navels and with light orange colored flesh; the navel oranges, with a distinct navel development at the end; and blood oranges, with red flesh and juice. There are about 73 varieties but US production focuses on Valencia, Washington Navel, Hamlin, Parson Brown, Pineapple and Temple. For home gardening there are many more than these six available from nurseries. Remember, in southern Nevada growing citrus is marginal. Our winters or just too cold. That is the major limiting factor. The usual reason for not producing fruit are winter freezes. Citrus should be planted in protected areas out of winter wind. They should be protected in the wintertime from cold. There is an excellent publication from Arizona on protecting citrus from cold weather. Protecting citrus from winter cold Arizona

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Orange Tree Flowering Now and Not December

Q. We have an orange tree that did not produce any flowers this last December.  Over the last week in March the tree has started covering itself with buds all over. We inherited the tree when we bought the house last summer so I don’t know much about the tree.  Just that its only a couple of years old and produced a couple delicious oranges in December of 2012. I’d love to have some oranges, but is fruit coming this time of year bad for the tree somehow?  A. No, you are okay with the flowers. They should sail through the summer with no problem. They probably got hit with a couple of freezed we had in December and January. My biggest worry is a late freeze which did not happen so you should be good to go. The best fruit will have some shade covering so it does not get sunburned. If it is in a container try to double pot it or somehow keep the sun off of the outside of the container. Keep it well watered as you would any other fruit tree or nondesert landscape tree. They do better with some surface wood mulch. Depending on the orange you should have ripe fruit some time late fall or mid winter. Hope this helps. You may enjoy reading this publication from Arizona on citrus.   Arizona citrus publication

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Suckering of Citrus Due to Cold Damage

Q. The low temperatures affected our citrus trees from last year.  Most of my new growth is on the suckers.  Should I remove them?  Or just let the tree be? A. If you look at the trunk of the tree you should see a bend in the trunk or “dogleg” where the top was budded or grafted on to the rootstock. I doubt if it is on its own roots which would mean you would see no bend or dogleg. Example of a “dogleg” where a fruit tree (in this case not citrus) was budded previously.             Anything coming from or below this bend should be removed and kept off. Whenever you see any type of growth at all from these spots it should be removed. If you let this growth develop it will rob growth from the part of the tree you want to keep and eventually dwarf or kill the good part of the tree.             Next you want to allow the lowest branches to develop from the trunk at a height you want these branches to remain. The distance these lowest branches are now will be the height they will be in ten years from now. I did not have a pic from the reader and this is not citrus but this will give you an idea of what suckers that are coming from the rootstock might look like. The suckers are dark brown. The trunk is whitish due to painting the trunk two years prior. These suckers need to be removed by digging the soil away from the trunk and removing them as close to the trunk as possible. Replace the soil after the wound from cutting has begun healing, normally at least 48 hours.             If these are too low then move up the trunk to a place where you want the lowest limbs to develop. Remove any of these unwanted lower limbs completely from the trunk by cutting them as close to the trunk as possible.             You can do this now if you want or you can wait until next January or February if there is fruit on them. I am not sure which citrus you have but if it is lemon they should probably be harvested in December.             Try to find limbs to keep which are coming from the trunk going in different directions. Hopefully you will find one limb going north, one south, one east and one west (I think you get what I mean by going in different directions as this will give the tree “balance” and reduce shading of itself).             On the limbs coming from the trunk, remove shoots going straight up or straight down. This leaves shoots that spread out in a fan (horizontally or laterally) but remove shoots that are growing up or down. This allows for better light penetration inside the tree and helps distribute fruit production throughout the canopy rather than just on the perimeter. I hope this helps.

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Yes, Remove Citrus Suckers

Q. The low temps this winter affected my citrus trees.  Most of my new growth is on the suckers.  Should I remove them?  Or just let the tree be.   A. If you look at the trunk of the tree you should see a bend in the trunk or “dogleg” where the top was budded or grafted on to the rootstock. I doubt if it is on its own roots which would mean you would see no bend or dogleg. Graft or bud union creates a “dogleg” on the trunk. Anything coming from or below this bend should be removed and kept off. Whenever you see any type of growth at all from these spots it should be removed. If you let this growth develop it will rob growth from the part of the tree you want to keep and eventually dwarf or kill the good part of the tree. Next you want to allow the lowest branches to develop from the trunk at a height you want these branches to remain. The distance these lowest branches are now will be the height they will be in ten years from now.  If these are too low then move up the trunk to a place where you want the lowest limbs to develop. Remove any of these unwanted lower limbs completely from the trunk by cutting them as close to the trunk as possible. You can do this now if you want or you can wait until next January or February if there is fruit on them. I am not sure which citrus you have but if it is lemon they should probably be harvested in December.  Birdseye view of limbs radiating from the trunk of a young fruit tree to provide balance. Try to find limbs to keep which are coming from the trunk going in different directions. Hopefully you will find one limb going north, one south, one east and one west (I think you get what I mean by going in different directions as this will give the tree “balance” and reduce shading of itself). On the limbs coming from the trunk, remove shoots going straight up or straight down. This leaves shoots that spread out in a fan (horizontally or laterally) but remove shoots that are growing up or down. This allows for better light penetration inside the tree and helps distribute fruit production throughout the canopy rather than just on the perimeter. I hope this helps.

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There is Lots of Salt in Las Vegas Water and It Can Affect Plants

Q. I saw that on August 12th you responded to a question regarding yellowing leaves on a Meyer lemon tree.  My tree has similar symptoms – though the yellowing is more spotty and on tips.  You advised to “give it a long deep watering about once every few weeks…to supplement the regular water to leach out the salts…” (emphasis added).             I realize that soil make-up effects watering needs, but can you give me a ballpark as to how many gallons of  “regular water” per week is needed for these trees in Las Vegas in addition to the leaching you recommended?  My tree is approximately 7 feet tall. Should I spread these gallons out over a few days a week, or is giving it these gallons slowing on a single day once a week? A. That’s actually a very interesting question and we have some research to back up the amount. There is about one ton of different kinds of salts (all of these together make up the “salt” content) in one acre foot of water that comes from the Colorado River (Lake Mead).  Rose leaf with salt damage             An acre foot of water is about 360,000 gallons. Unless you are on a well, this represents about 80% of the drinking and irrigation water provided by water purveyors (Las Vegas Valley Water District in the case of Las Vegas) in the Las Vegas Valley.             This sounds like it could be quite dilute but actually when you water to a lawn from Lake Mead it will carry 4/5 ton of salt for every 360,000 gallons that are applied. This translates to an application of 800 pounds of salt for every 1000 square feet of lawn area each year. Salt damage to pineapple guava from salt in the irrigation water             Bottom line, if this is municipal water it carries a considerable amount of salt. If you skimp on the amount of water that you apply and don’t overwater a little bit, this salt will accumulate around the roots of plants. This “little bit” of overwatering each time you water is only about 15%.             So if you apply 100 gallons you really should apply 115 gallons to help move the salts out of the root zone of plants. If it is 50 gallons, then apply an extra 7.5 gallons. Ten gallons means you should apply 11.5 gallons.             Few people are this precise when they water unless they are watering a golf course and paying $1M each year to irrigate an 18 hole golf course. So when you water you can apply a little bit extra each time you water (15%) or you can flush out the salts around the roots by adding an extra irrigation or two during the hot months to keep those salts moving out. I hope this helps.

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