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Saturday, November 12, 2022

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.


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Tree Planting Requires Proper Hole Preparation in the Desert

Q. I had a boxed mastic tree planted recently. I didn’t like how it was planted. It was planted with the trunk not straight, the top of the roots exposed, the soil in the hole was dry, and I had them remove the bottom of the box. They were going to plant it with the bottom of the box still under the root ball.

Mastic tree planted too shallow. Also the area is very small for such a large tree.

A. I looked at the pictures you sent to me, and I agree it was not planted well. Sloppy planting. The hole was dug too small, and it was not planted deep enough. About 30% of the soil should be amended for drainage and moisture retention. Out of sight, out of mind. The soil surrounding your tree may or may not have enough amendments added.

Watch this video on planting trees in Arizona that I thought was pretty good.

Mastic (Pistacia lentiscus) trunk was planted with the trunk at an angle which is less of a problem than the exposed rootball (above).

            Mastic is related to pistache (Pistacia lentiscus). Like all pistache trees, it is mesic in its need for water. This tree is Mediterranean in origin rather than western Chinese or Central Asian. Water requirements for both are similar and both develop red fall color. It grows well in a lawn where it gets plenty of water or surrounded by other mesic shrubs for the same reason.

            When planting on a slope, the lowest side of the hole should be used for judging the hole depth. Add water at the top and sides of the hole, not the bottom. This tree is fine growing in soil covered in rock. If this tree shows signs of poor growth in a few years, add a layer of compost on top of the soil and water it in. Water should be applied on the “uphill” side of the tree but three feet at least from the foundation of the house.

Dry Hole Problems

            The problem planting in a “dry hole” is removal of air pockets. Dry soil pushed into the rootball (and using the butt end of a shovel to shove it further) may or may not remove them. Usually not. When planting in a slurry of soil the air pockets are removed at planting time (look for the bubbles), less “transplant shock”, and less concern about tree stability (staking) after planting. Air pockets in the soil will not do that.

Wet the Soil

            Making a slurry is easy to do. Just use a hose during planting. Sometimes a dry soil can be compensated in the first few months by circling a moist rootball with a “moat” or donut on top of the rootball when planting and wetting the soil after planting. Either that or apply water slowly or several times to get it to soak in.

            This tree grows about 25 feet tall with about the same spread when fully mature. Pay attention to branch direction and the house when planting. Dig the planting hole at least three times the width of the plant container. Amend the soil removed from the planting hole with “organics” of some sort to keep the soil loose, friable, and well drained after planting.

How Close to the Home?

            I wouldn’t plant it any closer than 8 to 10 feet from a house to accommodate the watering and branch growth. Trees should be planted as close to vertical as possible. When trees are planted from a wooden box, usually the bottom of the box is removed first, and the sides are removed after lowering it into the hole. Fill the hole half full and then ADD water to make a slurry. Never add dry or hot soil to a planting hole.

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UNR Extension Tours of Southern Nevada Gardens

 


            Join the Master Gardener Docents, starting Saturday, November 12, for guided tours of the beautiful and interesting Extension gardens (corner of Paradise and Windmill) as well as its interior courtyard. Lots of different plants to look and learn about. Learn which plants performed the best and why? Learn which plants use the least amount of water and, finally, where you can get them! Dates vary to make it convenient for you! The tours are seasonal, so our fall series of tours is happening now, but the tours will stop in early December and will resume again in the spring, usually from April to June. 


            Tours are conducted two to three times a month from until April. Register in advance on Eventbrite by typing in Garden Tour in Eventbrite’s search bar. Future tours start mid-mornings and oftentimes last one and half hours. The tours are scheduled on Eventbrite and attendees need to sign up there.


            The Extension Botanic Gardens feature over 1500 species of plants, including many found nowhere else in the Las Vegas Valley! Docents lead attendees through highlights of the gardens and answer many different and tough questions about these plants and where you can get them.

            Please wear comfortable walking shoes! Tours are fun, informal, and full of exercise. Come join them! For more information call Lauren at 702-940-5432.

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Thursday, November 10, 2022

Location for Planting Meyer Lemon

Q. I have received two Meyer lemon trees. I want to know the best place to plant them. My house faces southeast, the sides are northeast and southwest, and backyard faces northwest. Due to very hot summer days is it best to plant on northeast side if house gets morning sun and shade in afternoon or in the backyard that gets more sun during mid-day to evening? Does direct hot sun harm trees during summer?

Meyer lemon fruit is ready to harvest from late December and into January. The orangish yellow fruit is more round than a true lemon and can grow about the size of a baseball. You better like lemons alot because when it gets older you can have lots.

A. All these places have their limitations. Probably the most damaging is direct late afternoon sunlight. Plant it where it will get some relief from the late afternoon sun. Plants in orchard are protected by other plants. In our hot desert the intense sunlight is very damaging. It can damage an open area (unshaded) of a fruit tree in less than 20 minutes. Then there are wind problems particularly, side yards where wind can “channel”. 

Leaf footed plant bug on citrus. Yes, they can be a problem on citrus.

            Meyer lemon (not a true lemon) is hardy to about 25F. Select a plant that is bushy with lower limbs as low as possible to shade the trunk.  It needs at least 6 to 8 hours of sunlight each day.

            Citrus will not like to be surrounded by rock unless the soil is amended. At planting time dig a hole deep enough for the container and three times wider. Make sure at planting time the soil is amended with compost or at least small pieces of wood that will rot with water and fertilizer.

            It is okay to surround it with rock but make sure the soil gets a surface application of compost or wood chips once a year. This may mean raking the rock back, applying it, water it in, and then raking the rock back. Or applying the compost/wood chips over the rock and watering it in if the rock is big enough so it does not become an eyesore.

            Be careful when pruning it. I would let it get established first as a bush and then remove lower limbs only as needed. Shade the trunk as long as possible. Sun, wind, and cold are the three things to worry about.

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Nutrgrass in Lawns Good Riddance!

Q. We have had nutgrass in our lawn (Tiff type Bermuda) for many years. There used to be a solution that would kill it or keep it at bay.  I haven’t seen it for the last 3 plus years.  It seems unless we can pull out the root and little “nut” at the end, it just keeps spreading. Any suggestions?

Nutgrass in a Tiff-type bermudagrass

A. Used to be that nutgrass, also called nutsedge both the purple and yellow types, were common problems in nursery soils. Once established in landscapes they were both tough to get under control because of the “nut” you mentioned. If the top was killed, the nut would regrow new “blades of grass”. The top, which looked like a lawn grass at first glance, would grow faster than the surrounding grass, or a light green color, and became a problem in well-manicured lawns or other stands of grass.

Nutgrass with an attached "nut" which oftentimes breaks from the mother plant when it is pulled. Leaving behind the "nut" is the most common way for this weed to spread.

            The best chemical control is with a product containing “Halosulfuron-methyl”. Look for this in the ingredients of the product. It may be called a trade name like “Sedgehammer” or others. That’s why its important to read the ingredients of a chemical and not just the trade or product name. This product may be hard to find so it may require buying it online from Do My Own pest control.

            It will require more than one application to kill the “nut”. The top will die, and you think it is dead, but the nut may regrow new “blades of grass” in a few weeks so watch for it. It is important to follow the label directions for these products exactly. In the past the problem has been the resprouting of the nut after the top died. It is very important to reapply this chemical as soon as regrowth is seen, or the spreading of the nuts will make the problem worse.

            The hybrid bermudagrasses are a good choice for lawns in our area. They can use about 25% less water than tall fescues lawns and typically have few weed or disease problems. Just for your information, the “Tiff-type” hybrid bermudagrasses come in different varieties such as ‘Tifdwarf’, ‘Tifgreen’, ‘Tifway’, and others. Tiff type bermudagrasses are used on golf courses and isn’t the same grass as our weed, Common bermudagrass.

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Toyon Can Develop Fireblight Since it is in the Rose Family

Q. Does this look like fireblight disease to you on established toyon? Toyon is in the rose family of plants.

Toyon can catch fireblight bacterial disease in the spring and summer months.

A. Toyon is a California native plant in the rose family and related to Photinia. Both plants are susceptible to fireblight. When the plant is dead it can be hard to say. Sometimes susceptible plants only lose their flowers and sometimes the entire plant dies. With prolonged wet weather this disease can be vicious. Sometimes plants “linger” with this disease, and it can lie dormant until cooler and particularly wet weather.

Fireblight bacterial disease on new spring growth.

            Look for bacterial “ooze” coming from wounds. This “ooze” are wet spots on tree limbs or the trunk. During wet weather this ooze may attract insects. Observing this plant can be a good way to know otherwise you have to send it to a plant pathologist and know for sure. Best way, when in doubt, is to assume its fireblight and remove it and get the dead plant off the property before it has a chance to spread. Be sure to sterilize any pruning equipment when you are finished.

Fireblight on Asian pear in early summer


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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.

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Monday, September 12, 2022

What Happens When USDA's National Organics Program Standards are Not Met?


The USDA organic regulations allow the AMS National Organic Program to issue proposed notices of suspension or revocation to certified organic operations that do not comply with the organic standards. If the operation does not appeal a proposed notice, NOP issues a final notice of suspension or revocation, which end the operation’s ability to sell, represent, or market product as organic.   

Oversight Update:
Certifier Exits and Appeals Process

Organic operations that are denied certification from a certifier or that receive a proposed notice of suspension or revocation may appeal that proposed notice to the AMS Administrator.  The AMS Administrator may sustain or deny an appeal, or AMS may choose to enter into a settlement agreement that achieves the goal of compliance.  If the AMS Administrator denies an appeal, the operation or certifier may request a hearing with a USDA Administrative Law Judge (ALJ).

The list below includes Final Notices of Suspension or Revocation issued by the National Organic Program, and AMS Administrator Decisions resulting from appeals. For each Decision, we have indicated whether a hearing has been requested with the ALJ. Operations  and certifiers that have requested a hearing remain certified pending the conclusion of their appeals.

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Sunday, September 11, 2022

Intercrop Plants With Roots That Grow to a Similar Depth

Q. I planted asparagus at the base of my fruit trees. I can send you pictures if you want.

Asparagus is short when harvested. But allowed to grow tall in recovery. Some asparagus will grow 5 to 6 feet tall.

A. Asparagus is a good thing to interplant with fruit trees, but it should be planted between the fruit trees, not at their base. They have similar watering needs, and their frequency of watering is very similar. That’s important.

            There are three things to concern yourself when planting at the base of fruit trees; increasing the amount of water needed, height interference with lower fruit tree branches, and a decrease in light for the asparagus growing under the tree’s canopy. That decrease in light directly affects asparagus production.

Intercropping between fruit trees requires light, water, and space. Here sesame is intercropped with fruit trees.

            Now onto where it should be planted. Plant intercrops between fruit trees rather than around their base. If you do, they will get an increase in the amount of light they receive, and they can grow as tall as they like without interference from lower tree branches. Intercropping like this works well with melons, squash, perennial herbs, perennial fruit, and artichokes.

Plants intercropped with fruit trees should have a deeper root system, require light and water.

            Unless you are using drip tubing you will have to add emitters if grown between trees. Drip tubing (built-in drip emitters) allows the roots of trees to “follow” the water and provides a wet soil for interplanting until the trees start to shade the area. When grown between trees asparagus height won’t be a problem later in the season. Asparagus is allowed to get taller after the spring spear removal for fresh vegetables.
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Figs an an Oasis Tree. They Need Water When Producing Fruit

Q. I planted various fig trees that were very good producers in southern California, Los Angeles County to be exact. Here they have been planted for over 10 years and I have yet to pick and eat any fruit from any of the trees! The problem that I am experiencing is fruit drop off. The figs grow to a fifty-cent piece and then they drop off.

Figs need water when they produce fruit even if the tree looks fine.


A. At the University Orchard and elsewhere I grew nearly 12 varieties of figs, and all have done very well. As long as they get enough water. Figs are what I call an “oasis” fruit tree. They handle the heat and do well and produce fruit if water is available.

Hot, Then Water More Often

            However, this is the desert. Our desert has two major problems when growing fruit trees like figs: soil improvement and water. Figs produce basically two crops of fruit. These are classed as the “briba” crop and “main” crop. The briba crop is the earliest because it produces figs on last year’s growth. This is also the crop that fails each year if there is a late spring freeze.

Figs produce fruit in different stages. First is the early or 'Briba' crop. The second crop of figs are produced on growth from this year and called the 'Main' crop.

            But figs also produce a “second” crop later in the year called the main crop. This main crop of fruit starts growing late enough in the season that freezing weather has gone. It starts to produce figs early in the season when it starts getting hot. It gets hotter so the tree needs more water to produce its figs. It is confusing because the tree shows no signs it needs water because the leaves look fine! But the figs drop off because the tree needs water. Very confusing!

            Those are the keys to successful fig production. Give it a productive soil and apply a two-to-three-inch layer of surface mulch.  Water it more often in the early summer even though the tree doesn’t look like it needs it.

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Texas Olive Froze at 25F or More

Q. I have a Texas olive tree that may or may not have survived this past winter. We have had the tree for several years now and it has always bloomed and grown. I don't have any new leaves or blooms except the suckers on the bottom.  All our other trees like our sumac, Palo verde, and fruit trees are doing fine.  But not this one. Is there anything I can do at this point beyond just watching it?

Texas Olive, Cordia boisieiri, hardy during the winter to about 25F, about the same winter temperature as Myers Lemon.

A. That particular tree, Cordia boisieri, is native to the desert southwest Chihuahuan desert and survives to a winter temperature of about 25F; around the same winter temperature as Myers lemon. Because it’s from our desert southwest it is considered xeric in its water use. Lots of good that does you if it is winter killed or severely damaged. 

A better choice might be Littleleaf cordia, a smaller tree and found growing on East Flamingo in Las Vegas.

A better choice might have been another xeric tree from that area such as little leaf cordia, Cordia parvifolia, which seems to survive to a slightly lower winter temperature. I suggest in the future, permanent trees in your landscape should have a minimum winter temperature of 20F.

Suckering from the base is a good indicator it died to the ground, or the trunk was severely damaged. You do not need to replace the tree unless it looks horrible. It is grown on its own roots. Let one or more of the suckers replace what died. Suckers grow very quickly if the roots were not damaged.

If a tree does not normally produce suckers at its base, the production of suckers can sometimes indicate the trunk is damaged either from borers or sunburn or both!

If you decide you want to keep it, water deeply and infrequently and fertilize it in the spring. Two handfuls of tree and shrub fertilizer about two feet from the tree each year will be enough. Wet the soil, create a slit in the soil with a shovel about 6 to 8 inches deep, drop the fertilizer into the slit, step on it to shut it and water it in. Xeric trees grow rapidly with water applied to them like mesic trees. You will have to search to find this tree at local nurseries.

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Large Orange Tree and Early Peach Presenting Problems

Q. I have both a ‘Washington’ navel orange and ‘FlordaPrince’ peach tree planted this spring that a local nursery claimed was 8 to 10 years old. The peach tree produced lots of small fruit, but the orange tree produced tons of flowers but fruit that dropped from it after it flowered. The trees don’t look so good now. Your opinion please?

'FlordaPrince' peach tree three years in the ground.

A. It sounds like many issues may be involved. Pictures would have helped. As it stands right now there is not much you can do. Some years you will get a good harvest and other years you won't. That is the nature of the varieties and location in the landscape you selected. Much of your future harvest depends on the weather, fruit tree location and the microclimate of your landscape. That's the Mojave Desert for you. In the future remember this.

Avoid Buying Large Trees

Next time select smaller trees with low branching at the beginning. If there are production issues, then they can be ironed out early. It is important to shade the trunk as quickly as possible when growing fruit trees of any type in the desert. 

Even though this peach tree was growing in or near a lawn it did not have enough shade to protect it from the hot desert sun common to the Mojave Desert.

Shading the trunk can be done with its own growth, painting the trunk or shading it with a trunk protector. However, it’s easier to remove branches that you don't want than to wish you had them. Our hot desert sun can be very brutal. I am leaning more and more toward leaving the lower branches (below the knee) on fruit trees as long as possible rather than remove them at planting time.

Consider Different Varieties

Consider different varieties of fruit trees. Both varieties may not a wise choice for different reasons. ‘FlordaPrince’ peach is an early producing fruit variety that also flowers very early, about mid-February in our climate. Selecting a variety of peach that produces flowers later gives you a more reliable harvest in our climate due to spring freezes.

Yes, that's right. Peaches from 'Earlitreat' peach in May in North Las Vegas, one of the earliest peaches. Producing early peaches can present a whole host of problems if your weather and microclimate don't cooperate.

Selecting a more cold tolerant orange type (such as a clementine, aka, tangerine) is sometimes a better idea. Selecting a fruit tree that gives you improved tolerance to freezing winter temperatures may be a better idea in the long run than a ‘Washington’ navel orange which doesn’t. Selection of a cold tolerant variety does not help provide a consistent fruit load every year but may help its future survival.

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