citrus – Page 3 – Xtremehorticulture

Protect Citrus From Freezing Temperatures Soon

Leave a Comment / citrus, cold damage, orange, winter freezing / xtremehorticulture

Q. When should I begin to protect plants like citrus from the freezing weather that’s coming? A. Some citrus will handle the cold weather better than others. Most of the citrus sold in this area are grafted to a cold hardy root system called a rootstock. Damage or even death results when the temperatures remain low enough to kill the top of the tree, its root system or both. This citrus died from winter freezing temperatures several years ago and the sour orange rootstock grew in its place producing oranges that were too sour to eat. The more cold hardy and reliable citrus here are kumquat, grapefruit and Myers lemon. However, they will not survive the cold if the roots which they are grafted to are not cold tolerant as well. Most plants sold by nurseries in this area have citrus on cold hardy rootstock. This might not be the case if you buy citrus online. Spring freezing weather caused this fig to die back and push new growth from lateral buds along the stem. None of the citrus are severely damaged if temperatures remain above 32° F. The least cold tolerant of the citrus, such as limes, is damaged when temperatures drop below freezing. When temperatures are low enough to damage the top of the tree but not the rootstock, suckers or water sprouts grow from the rootstock the following spring while the top of the tree may be dead or severely damaged. Freeze damage to bougainvillea As we start getting close to 32F, start watching the local weather reports or track the low temperatures online. When you see projected temperatures reaching 32° F or lower, wrap the base of the tree with a blanket or cover this area with mulch. Smaller trees or trees pruned into an espalier may be entirely covered with a blanket. Some people wrap tender trees with Christmas lights on a timer that comes on at night. This may work if temperatures are not extremely low and there is no wind. Blankets should be removed the next day when temperatures climb above freezing.

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Harvest Oranges Before a Hard Freeze

Leave a Comment / citrus, when should I harvest oranges / xtremehorticulture

Q. After 6 years, I am finally getting oranges. They are turning orange and I have been told not to pick them until mid January. Is this right or can I pick them now (mid-December)? A. Different varieties ripen at different times. I would sample one now and if it tastes good to you then harvest the others at the same maturity. If it is not yet to your liking then wait a bit but if temperatures drop to the mid-20’s then the fruit might freeze. In the Las Vegas area we get our coldest weather NORMALLY from mid-December to the end of January. Play it by ear a bit right now but normally they would be ready right about now. You do not want to wait too long because fruit remaining on the tree can interfere with new flower production. I copied and pasted this citrus calendar from the University of Arizona pdf document you can download from HERE. These are the approximate harvest dates (this is for Maricopa County, aka Phoenix area). We are a bit colder so harvest times can be a bit later. However for areas like Laughlin and Bullhead City they would be on the mark. Note: I am recommending citrus in the Las Vegas area in only warm microclimates or protected from winter cold and winds. The chart below I copied and pasted from the University of California Riverside pdf document you can download HERE. This tells you the critical temperatures where you might lose different parts of the tree (flower buds, blossoms, green fruit, ripe fruit).

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No Fruit on Dwarf Orange

Leave a Comment / citrus, flowering, flowers, fruit, fruit production, orange / xtremehorticulture

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 or if the flowers formed but failed to produce 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. Here is a publication from Arizona on citrus varieties. extension.arizona.edu/pubs/az1001.pdf

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Pick Fruit and Check for Circling Roots When Repotting Lemon

Leave a Comment / citrus, container, desert, girdling roots, Las Vegas, Mohave Desert, Mojave Desert, nevada, planting, pot bound, potbound, replanting / xtremehorticulture

Q. I purchased a lovely Meyer Lemon tree in a one gallon pot in middle of the spring. It already had 6 lemons on it. I have the original fruit, have new fruit growing, and still am getting blossoms. Should I transplant it now into a larger pot or wait until after the fruit ripens and is used? A. Remove any mature lemons from the tree. Lemons should not remain on the tree longer than about late December and possibly early January at the very latest. Check for circling roots in the container before planting. This is early enough you might be able to correct it. Leaving lemons on the tree can disrupt the flowering fruiting cycle for the next season. If you are planning on putting it in the ground then I would just wait until you have that spot prepared if it is this spring. If you are planting this fall then you might want to repot it into a larger container and wait for fall planting. When circling roots get to be this far along they can no longer be corrected. If you do repot, check the roots for circling inside the container. This is a common problem in nursery grown trees, called “potbound”, sold in containers. Planting a tree with roots circling in the container and not trying to fix this problem before planting can lead to some serious problems down the road.

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Repairing Lemon Trees From Winter Cold Damage

Leave a Comment / citrus, cold damage, desert, freeze damage, Las Vegas, Meyer lemon, Mohave Desert, Mojave Desert, nevada / xtremehorticulture

Q. Our lemon tree shows damage after our recent very cold spell. Some of the leaves are dry and dropping. Is there anything we can do to assist the tree? A. The damage can take several different stages. The degree of damage depends on the lowest temperature reached, the amount of time at this temperature and the source and condition of the plant. The first stage is slightly below its tolerant range and results in leaf damage and other soft tissue death while the stems remain relatively undamaged. The second stage is at temperatures slightly lower or held for a longer period of time. This results in leaf damage or leaf drop and death of smaller stems. The third stage is complete death of the limbs and trunk back to the rootstock. The rootstock is normally a very hardy citrus grafted on to the more tender citrus. In this third stage the more valued lemon portion of the tree completely dies but leaves behind the more cold-tolerant rootstock. When temperatures warm, the rootstock will sucker into a totally new, but different, citrus tree. You can get some idea now by bending some branches and see if they are supple and bend or if they snap off. But you will not really know the extent of the damage until you see new growth in a month or so. Once you see where the new growth is coming from you can make a decision to keep the tree or remove it and start all over. If you have suckering from the limbs then you might want to prune it back and let it regrow. If suckers just come from the roots then it would be wise to remove it.

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Blood Oranges Not Best Citrus Choice for Las Vegas

Leave a Comment / can you grow citrus in las vegas, citrus, small fruit / xtremehorticulture

Q. Blood oranges. Why are they not growing? They grow to golf size balls and that is it. Why? A. I don’t know which variety you have and how or where in your landscape you planted it. Blood oranges, in my opinion, are a bit more sensitive to our desert climate than some other citrus. Citrus is one of the fruits that doesn’t really respond to thinning very well. Very little difference in fruit size is seen in citrus if it is thinned like you would apples or peaches. So thinning will not make the fruit larger. I think you will have to focus on better tree management. Put them in an area that is not quite so hot and has some shade from late afternoon heat. I would try mulching under the tree with wood mulch and make sure you’re irrigation is adequate. Keep the mulch at least 6 inches away from the trunk to prevent trunk rot. Have at least two drip emitters irrigating this tree about a foot from the trunk. Another sign of a problem in water management can be fruit splitting. Myers lemon and grapefruit would be a better choice. Even Satsuma orange would probably be a better choice than a blood orange. Blood oranges will freeze back in our climate so you will have to protect them from freezing during the winter. Locate them near a warm wall and protected from winter wind. If you are going to try a blood orange see if you can find a variety called ‘Tarocco’. If not, a second choice might be ‘Moro’ but if you are not willing to protect it from freeze damage, then don’t plant it.

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Orange Tree Dropping Fruit

Leave a Comment / citrus, fruit drop, navel orange / xtremehorticulture

Q. My orange has lots of blossoms, they begin to set the fruit, but when the fruit becomes the size of a pencil eraser, the fruit drops off the tree. What is going on? I watered it, and applied fertilzer. A. I have two questions that might shed more light: 1. Is this tree planted less than three years ago? and 2. Is it a Navel type orange? Sometimes it takes a few years for the plant to come into enough maturity to set and hold the fruits. . . . And dropping fruits is a common complaint with Navel Oranges. . . They set fruits and when the heat hits or the first dry wind and they slough off most, if not all their fruits. . . With time more and more will fruits will make it to maturity. . .. Most people are disappointed with the quantity of Navels but not the quality. Terry Mikel

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Watering Citrus in Bullhead City

Leave a Comment / citrus, irrigation / xtremehorticulture

This is an irrigation basin around a fruit tree. The basin keeps water contained near the tree where the roots are. This basin receives its water from a bubbler (upper left inside the basin). This particular bubbler puts out two gallons per minute if the water pressure is adequate or above (it is pressure compensated which means if the pressure is higher than adequate it will still give only 2 gallons per minute) I have three trees planted in a “L” shape with the orange and lime on the bottom of the “L” and a lemon on the top. They are about 6 years old and the trunks are about 5” in diameter. They are almost 6 ft. tall and about 7 ft. in diameter. I have the three on a separate circuit with each having a 1/2 “ p.v.c. bubbler providing water every other day at 6:30 a.m. and 8:30 p.m. for 15 minutes. this fills a water well that is about 4” deep and 4 ft. across for about 10 minutes after the water goes off. The water is then absorbed into the ground. I have tried to let the water run longer but it seem’s to want to go outside of the well and not deeper into the well. I thought about cutting down on the flow so it would run longer and maybe soaked in to the well better but I have not tried that. I have been told to water once every 90 days and let it run for 3 hours. I would have to cut the bubblers just to a drip or it would flood the yard. I don’t know what is the best option. I get a heavy crop of limes now but just a few oranges, and they are half orange and half green. any suggestions? Remember this is in Bullhead City and it gets very hot during june thru sept A. I forwarded your question to Terry Mikel, retired Extension Horticulturist with the University of Arizona out of the Phoenix office who knows your location very well. Here it Terry’s response: I am familiar with much of the Bullhead City soils and conditions but I have yet to hear that watering every ’90’ days . . . I should think, or hope someone might have meant or you meant every ‘9’ days .. . That would be certainly a point of clarification . . Irrigating citrus in Hermosillo, Mexico, at USON’s research farm. This is ditch irrigation which is terribly inefficient but still more efficient than flooding the entire field. Water moves toward the roots from the ditch through the soil. The most efficient would be drip irrigation and would not need a basin or ditch but is expensive for farmers with hundreds of acres. I personally avoid giving calendar or numerical days for watering . . There are too many factors; for example, are you near the river with a heavy clay soil or up on the higher ground where the soil drains much better? . . . It sounds like you are careful and meticulous about watching the growth and you should check the soil in the morning hours and water when it is dry down a couple inches . . .Remember to check in the morning not in the afternoon when the heat will dry all soils there down a couple inches . . In the morning the soil will have the cooling of the night to percolate water up from below thus rehydrating (fancy word for wetting) the upper soil zone . . . If you want to add more water and much more efficiently then change how you add the water . . Set the repeat cycle to whatever time it takes the initial water to move into the soil and then run the set again instead of spacing it out for hours . . This is called surge watering and it works much better than the delay . . . Maybe next summer you can try and see if you can go more days between waterings without impacting the plant . . If you have a fast draining soil it might not work; likewise, if your soil is heavier you might . . . Don’t forget that a nice thick layer of mulch on the soil surface saves a lot of water from being lost into the air through evaporation . . . There are some great Master Gardeners in your area that are both knowledgeable and grow lots of things under your conditions . . With respect to the lime’s yield vs. the orange’s yield: My first guess is the orange is a Navel type orange . . They are notoriously sensitive to hot dry condition and their fruits drop like flies . . The plant itself does well but the fruits you get are great but the number you get is usually a disappointment . . .It’s almost a shame they are sold . . . Terry Mikel

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Yellowing of Meyer Lemon Tree Leaves Hard to Correct

14 Comments / chlorosis, citrus, yellowing / xtremehorticulture

Q. We went and talked to nursery folks a couple times about this tree. First we got the water cycle correct, then iron was suggested which we did as directed. Then a soil amendment was suggested. Online I read possibly the tree suffers from a magnesium issue. I thought these photos would give a better picture. We did as directed and the tree is not responding in fact it is getting worse. I am wondering if it is because of where it was planted which is a confined root growing area. Any insight would be appreciated. Readers lemon tree with yellowing leaves A. By looking at the leaves I have to assume this is a Meyer Lemon (which is, by the way not technically a lemon but an unknown hybrid found in a Chinese back yard by USDA researcher D. Meyer in the early 20th century). Your pictures are all pretty good with the exception of not showing a critical view of the trunk where it is just out of the soil. Just for future reference always look at and show this interface of the trunk and soil. W/o that view I have to only guess that the rootstock/trunk union is well out of the soil and we can eliminate that issue. And, a shot of the soil might show how the plant is getting watered. I have to assume drippers and I would guess they are in the same locations as when the plant was planted. Closer look at readers yellowing leaves The leaves show two distinctive symptoms that often occur in concert: 1. There is some salt burn and 2. The common symptom that comes with salt issues is the magnesium deficiency. Just FYI Iron deficiency only occurs on the new leaves. For the salinity (salt) issue we usually look first at the watering and with watering comes knowing if the water can even be applied uniformly all around the edge of the canopy, sometimes called the ‘drip line’. Citrus are botanically a shrub with shallow and wide spreading roots that are tough to grow to maturity with drippers unless they are closely spaced in a wide band around the canopy’s edge. There is one picture showing the plant is right next to a step wall with no water being applied in that zone of the root system. Clear look at the yellowing or chlorosis problem on readers citrus I would not worry too much about adding any supplements and see if you can begin to manage a watering system of application that would give a long deep soaking water application out near the drip line. The ‘soaker’ hoses could be laid out on the ground out near the drip line and let it run for hours and hours to try and leach out the excess salts that may have accumulated over time with the drip system. Drip systems are fine but, due to their limited water output salts can begin to accumulate thus impacting citrus’ sensitivity to salts. Give it a long deep watering about once every few weeks from now on all during the growing season (May through October) to supplement the regular water to leach out the salts that inevitably are deposited with the limited volume of drip systems . .This leaching watering is also the great time to add fertilizer and get it into the soil evenly all around the active roots near the drip line. -Terry Mikel

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Sharp and Soft Thorns on Rio Red Grapefruit a Problem?

Leave a Comment / citrus, different thorns, should i remove a branch with thorms / xtremehorticulture

Q. I read your answer few weeks ago to questions concerning sharp thorns on branches growing from the base of an orange tree. I have a Rio Red Grapefruit semi dwarf tree which is about 3 feet tall. The main trunk is topped buy 3 branches spreading out in different directions. One of the branches has several sharp thorns on it as well as soft thorns to very soft thorns on it. The other branches do not have sharp thorns. My questions are 1) should this branch be removed or is this a normal occurrence and 2) will the sharp thorns soften in time? A. Robert passed this to me and before an answer can be given we need to make sure of something . . . The branches with thorns, are you 100% certain they are not a shoot arising from the rootstock? . . Follow it back to where its connected to the trunk and if it arises from down low near or below the soil line then cut it off as it is a rootstock sucker. . . Otherwise, many Citrus shoots have thorns that start out soft, become rigid and then, over time most get absorbed back into the plant with maturity. . . . The thorns invariably are on vigorous vegetative shoots that need a period of time before they convert to flowering and fruit producing tissue . . . If the branch isn’t hanging near where people walk by and could get stabbed then let the branches go . . Over time they will change from the vigorous to the more sedate fruit producing wood and the thorns will be but a memory . . But first make sure the branch(es) with the thorns aren’t from the rootstock . . . You do understand the cost for this advice is for you to share those beautiful Rio Reds with friends and neighbors. . . Terry Mikel

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