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Saturday, June 19, 2021

Ash and Plum Success Stories

 

Fan-Tex ash tree about 17 years old. Front yard.

At least 17 years old.  When I got to take care of it 10 years ago, it was on its last legs.  Plenty of bone meal and water. It has great drainage.  I did apply some 30 year old insecticide for ash borers on the trunk about 5 years ago and probably some of that systemic rose fertilizer. The only ash tree in the neighborhood.


Santa Rosa plum tree in the back yard. Notice that the water is applied through drip emitters that apply water to the soil surrounding the tree and covering at least half the area. Also notice that the soil is covered in wood chips that decompose and enrich the soil with organics as they rot near the water.


Friday, June 18, 2021

Planting Peach Tree in the Summer Not Ideal but......

 Q. Here is the hole where I will plant the peach tree.  Still have to add some more top soil/compost mix.  Plan on shading the tree with 40% sun fabric for the first year.  Will mulch heavily but 8 inches away from the trunk.

Planting hole was dug super big and the soil from it was mixed with compost.


A. Planting in the middle of summer when it is hot in the desert is not the best time and not really recommended but it can be done. How?

Not recommending for this time of year but it can be done. Here is how.


1. 
Predig the hole at least three times wider than a five gallon container. Mix the soil from the hole with a rich compost like you can get from Viragrow, about 25% in the summer (one shovel full to three shovel full of soil from the hole).  Fill the hole with water before you get the tree.

2. While you are out and about getting the compost, get a garbage bag or two full of wood chips from the University Orchard in North Las Vegas. Call 702-257-5555 for directions and availability. You need enough to cover the area around the tree, about six feet in diameter, with wood chips.

3. Pick out a tree in a five gallon container that is healthy with low branches. Small is good as long as it is vigorous. Also buy a role of green nursery tape. When you get home, water it and put it on the north side of the home until early tomorrow. Do you have rabbits? Then pick up some chicken wire.

4. When it is first thing and cool out, remove the plastic container, fluff out the roots quickly, and put it in the hole. It should be the same depth in its new home as it was in the container. Slowly fill the hole with water and  put the amended soil around the fluffed out roots. You should see air bubbles escaping from the planting hole.

5. After seeing no more water on top of the soil, stake the tree so the roots dont move. Cut the green nursery stake free from the tree and pound it in the soil right next to the plant until its solid in the ground beneath the hole. Re-tie the plant back to the nursery stake. Apply wood chips three or four inches deep around the tree but keep it 6 to 12 inches away from the tree trunk.  If you have rabbits in the area, protect the tree with a two foot tall cylinder made from 1 inch diameter chicken wire. If rabbits chew on the tree, it is a goner. Rabbits love to chew on fruit trees. In and is there a the culture and I thinking I just Russians I you and so I'm thinking you'll find in your area will you as you are serious a serious and you will is maybe is a good time love you the possibility is very about the you because I think it would be a mistake to buy anything is very Las Vegas is is expensive but I keep it open is maybe you are a places that can be pretty easy to talk more about the money find this in a you will

6. Do not fertilize if you used rich compost like the kind you get from Viragrow. Water it with a hose the next day and then every other day until you see new growth. Once you see new growth and it is hot outside, water three times a week.



Why Branch Falls from a Tree

 Q. A mesquite tree of ours dropped a limb. Why did this happen? Is the tree safe?


Tree branches are filled with dead wood on the inside with a small cylinder of living wood that surrounds it. This interior dead wood rots very easily if you are not careful.

A. To give you a quick answer to your questions, I think the branch was weakened by a disease and it fell from the tree as the result of wind. It is impossible to judge if a tree is healthy enough so that it will not drop any more limbs from just pictures. It needs a visual inspection by someone qualified to make that judgment. I would recommend a licensed arborist, such as First Choice Tree Service, who holds those credentials and can make that recommendation. By the way I don’t get any compensation from anyone I recommend. It’s all word-of-mouth. I might add there are many licensed arborists to choose from in the Las Vegas area.

Suckers growing from the African sumac trunk after pruning.


When trees are growing very small shoots or suckers then everything inside of those small shoots can carry water between the roots and the leaves. As these suckers get larger, the inside dies and becomes deadwood. This leaves only a cylinder of living wood just under the bark of the branch that remains alive. Everything on the inside of this living cylinder is dead wood. Because this is dead wood it is easily rotted by just about any rotting fungus that comes along. This is why it is extremely important to protect the tree bark from damage. 

The bark on a tree gives the inside some protection from the elements.


Tree bark protects the dead interior of these limbs from getting infected and rotting. If someone comes along with the dirty saw, lopper or pruning shears that’s carrying a disease from another tree and these tools are not sanitized, it is possible to spread this rotting disease from tree to tree. This is why I harp consistently and continuously on sharpening, adjusting and sanitizing your pruning equipment at the beginning of each pruning day. Also, when you think one might be sick. I would suggest encouraging landscapers who are pruning your trees to do the same. It just takes one time for the disease to in fact a tree that was previously healthy. Would you go to a doctor’s office and allow the doctor to use a dirty scalpel on you? Show the same courtesy and respect for other living organisms like trees and shrubs.

Using an alcohol wipe to clean and disinfect a loppers.


Once this rotting infection enters the tree or shrub it can spread through all of the interior dead wood throughout the plant. It usually stops rotting the dead wood were the limb attaches to the trunk. That’s a natural place where it will stop and not spread to the entire tree. Once this interior dead wood becomes rotten, the inside of that limb or branch is weakened. If a strong wind moves these branches they can break because they no longer have the strength they had when the interior was filled with dead wood.

Most likely this branch was rotten on the inside, lost the strength it had from dead wood in its interior and broke with a strong wind. If you look closely at the limb that fell, you will see that it’s rotten on the inside and may be able to identify where this rotting disease entered the branch. Most likely it did not spread to the rest of the tree but that tree safety should be left in the care of a certified arborist.

Crape Myrtle Can Be Grown in Desert Soils

Q. I planted this crepe myrtle the first of May. I recently noticed leaf curling and now the brown edges. I’m watering with 6 “ inline tube emitters every other day for 20 min. It’s located in a very hot spot in a corner with south and west facing walls. Any advice would be appreciated.


Crape myrtle newly planted and growing in a raised bed.

A. The browning along the leaf edges either means though tree is not getting enough water or it is being watered too often. The crêpe myrtle will not like hot locations. It doesn’t like hot locations unless you are a very good gardener and can manage that heat and water it needs.

I certainly wouldn’t water more often than every other day. I worry a little bit about two things; is the soil staying too wet between irrigations and secondly is the water getting deep enough when you are watering. 20 minutes of watering doesn’t tell me much. I drink 16 ounces of coffee in 1 ½ minutes. I like coffee when it’s hot. Some other people they can sip on this coffee for one hour. So, 20 minutes doesn’t mean much to me. A crêpe myrtle that size needs about 10 gallons of water. It can get it in 20 minutes or one hour. It doesn’t matter.

Crape myrtle watered with a basin and bubbler, fertilized once a year and using EDDHA iron chelate as its iron source, No organics added to the soil.


I noticed you have what looks like vinca or periwinkle planted with the crêpe myrtle. That is a no no. Vinca or periwinkle has roots that are shallow growing to about six or 8 inches deep. It likes to get frequent watering. The tree on the other hand has roots that are as deep as 18 inches. It likes to get water less often than the vinca but more applied each time. Unless you are a very good gardener and can manage the water between the two the mixing of these two plants together can cause problems in watering. I suspect that’s what you’re seeing. Other deeper rooted flowering plants like rosemary would be a better choice since it has deeper roots and a more similar watering regime.

What to do? 

I am not sure how much water that laser tubing is delivering in 20 minutes. The water for the tree should be applied so that it penetrates the soil each time to a depth of about 18 inches. Then the idea is to hold off on watering again until the soil begins drying in the top few inches. That might be one day or it might be two days I’m not sure. An inexpensive soil moisture meter like for house plants would tell you that. 

Inexpensive soil moisture meter used for monitoring irrigations. Push it in three or four inches in several different locations.


Push it into the soil in three or four locations about three or 4 inches deep and don’t water again until it reads Midway or about five on the 10 point scale. The periwinkle are vinca will drive your watering cycle since they are more shallow rooted.

The other problem you’re going to have with crêpe myrtle during the summer months is its location. As you pointed out it’s very hot in that spot. The crêpe myrtle will improve and looks in October and November but it will not like it there during the heat. The most successful locations for crêpe myrtle in Las Vegas has been on the east or north sides of homes where it’s a bit cooler.

Why Branch Fell off of Mesquite Tree

 Q. This large branch suddenly fell off our 22 yr. old Mesquite tree. We have no idea why. Any thoughts?

When a stem becomes a branch, there is just a thin cylinder that is living inside this branch. The rest is dead wood.

A. When stems are first growing and just young small suckers the entire inside is living and pumping water up and down to the leaves and roots. If this upright sucker is getting plenty of water and lots of light, the growth of this sucker will be fast. As this young stem becomes older and larger, the inside of it dies and becomes dead wood. But inside every large branch there is a cylinder of life protected by the bark that is alive. Instead of having small suckers, stems, that move the water up and down these larger branches don’t need that much living parts of the stem and so this internal "vascular tissue" dies and becomes the internal but dead wood. This internal wood strengthens the branches and keeps them attached to the tree. 

Branches are dead on the inside. This cylinder of living wood inside the branch is "rolling over" the dead wood inside and will eventually fully transport water back and forth between leaves and roots.


Internal Wood is Dead but Strong

This internal wood, since it is dead, can very easily decompose if infected. The outer bark of a tree protects the wood from rotting but if it is damaged by improper pruning or a knife or other accident, then this dead wood on the inside can become infected and die.

 Your Mesquite Branches

The internal wood of this stem on your Mesquite tree has rotted. The stem has weakened because the internal dead wood has rotted or is rotting. This is why I encourage people to sanitize the saw, lopper or pruner before cutting into the bark. Sanitizing sharp pruning instruments helps to protect the internal wood from getting infected, rotting and weakening the limbs. Dead or dying limbs are blown off the tree more easily than strong healthy limbs.

 

This mesquite tree is infected with slime flux or wetwood disease which is common on mesquite. This bacterium will rot the interior of the branch and weaken it.

If you look closely at the internal damage of this branch, most likely you will see where the bark has been injured and disease rotting organisms have gained a foothold inside the branch.



Thursday, June 17, 2021

Three Reasons for Spots in a Lawn (Uhm, four)

Q. My hybrid Bermuda grass lawn from seed is coming along well but have this spot that is turning yellow.   Any thoughts?

Spots developing on a seeded hybrid bermudagrass lawn.

A. Do you have a female dog? The brown spots on the bottom of the picture look like dog spots from peeing. Brown spots from dog pee are usually greener at the edges of the spot and then get die in the center of spots that are about 8 to 10 inches across. But there is browning in the center of the picture as well.

Urine damage from dog


Checking for Insect Damage

Yellowing in spots can result from several possibilities. The possibilities are insects, watering or disease. Let’s eliminate one at a time and discover the most likely reason. The easiest to determine our insect problems. On the edge of the yellow area where there is a mixture of green grass and yellow grass pull on the grass like you are playing and pulling at someone’s hair and jerking their head back. Not rough but gently pulling. Most insect problems cause mechanical damage to the plant. When you pull on the grass and it has damage from insects, the grass comes up easily and to severed from the roots. You will get a mixture of green grass that looks fresh and dead grass in your hand. The insects that cause this damage are white grubs usually in the spring and side webworm in the summer. If this is the case and you find this true, then go to your favorite nursery or garden spot and by an insecticide to kill the grubs or side webworm. 

Not Insects?

Now let’s say the yellow spot is not insects. The next category we have to eliminate is disease. Most diseases when they are present will leave a few brown spots on the leaf blades and stems or dieback on leaves or spotting. When you are on your hands and knees checking for insect damage, also check the leaf blades in those areas for disease problems such as small brown spots. This is less likely than insect problems but if you think it might be a disease problem then go to your favorite nursery or garden center and by a fungicide for lawn diseases and make the application. Some lawn diseases can be spread from lawn to lawn by mowers.


Not Insects or Diseased?

The third reason can be irrigation, if you just started this lawn it went be too often and keeping the soil too wet most likely. Once the seed has germinated and the lawn is growing you should not be watering more than once a day. With Bermuda grass you might be able to water every other day even when it’s hot. The only way to know is to try and but definitely not more than once a day. Don’t water your grass again until you see any signs of water stress on the grass. 

Footprints when grasses like fescue need water


This is a smoky green color or when you walk across it it’s leaving your footprints in the grass. This tells you it’s time to water again. In the summertime when it’s hot you can’t fool around and wait a day to get the irrigation on. You must water it as soon as you see it when it’s hot. In cooler temperatures in the 80s you can go a day without watering and it won’t affect the lawn but not now.

Canary Island Date Palm with Dying Fronds

Q. Canary Island date Palm with one or two fronds browning and dying. What to do?

Canary Island Date palm with individual frond death


A. Please be aware of that Canary Island date palms can grow to 50 or 60 feet high so they are too large, in the long run, for residential landscapes. These are huge plants. But these palms grow slowly so it will grow slowly. There are several things that could cause the fronds of this palm to die. The most serious is a disease called Fusarium. You can Google the images and look to see if it resembles Fusarium or not. If the palm tree has Fusarium disease it will most likely not recover but it will get worse in time. If you think the palm trees are infected with Fusarium it’s best to remove them before they get larger and more expensive to remove. The other problem with Fusarium is that it contaminates the soil so few trees can be planted exactly in the same hole. It’s best to plant something close to it but not in the hole. Fusarium is caused by wounds to the palm tree oftentimes caused by improper pruning and sanitation of the pruning equipment and then weakening the palm tree by watering it too often.

The most common problem facing people growing Canary Island date palms in the Las Vegas desert are not amending the soil at the time of planting and watering too often. Watering too often keeps the soil wet and weakens the palm. Pruning these palm trees with dirty pruning equipment causes the disease to enter the plant and watering too often or poor drainage makes the plant unhealthy.

What can you do? 

If you are convinced this palm probably has Fusarium disease, then remove it while it is still small and young. Not many trees and shrubs are resistant to Fusarium. It’s a very aggressive and nasty disease. Make sure the soil around the plant drains water, do not watered too often but if you are watering too much then give it too much water rather than too often.

These can be expensive plants. It might be an expensive educational lesson.

Tuesday, June 8, 2021

Read Up on Ash Decline and Decide What to Do

 Does Ash Decline Exist? 

'Modesto' ash in a lawn and its dieback.


Read up on the tree disease here, here, and here and decide for yourself.

What is known?

In Las Vegas:

The "condition" was reported by landscaper Nanu Tomiyasu to Yours Truly in late 1980's on mature, 30 foot tall mature Modesto ash trees growing in a lawn near Cashman Field. The trees were given supplemental water and fertilizer but removed when they failed to respond. Yours truly took the State Pathologist, Dr. Wally Sheta, to the site where he thought it might be Ash Yellows and a sample was prepared and sent to the University of Florida for confirmation. The report came back negative for Ash Yellows and this "condition" was not pursued after the trees were removed. It has since been seen in Las Vegas on varieties of Modesto, Raywood, Fax-Tex and Rio Grande ash trees.

In Arizona:

This "condition" has been reported in Arizona by Jeff Shalau in 2018 after an investigation begun by Extension plant pathologist Dr. Mary Olsen started in 2009.

This condition has been reported in the Journal of Arboriculture by Bricker and Stutz in 2005 as a tree disease and MLOs are suspected to be the cause.

All trees infected by this condition die a slow death regardless of irrigation and fertilizer applied. 100% mortality. To my knowledge no pesticides were applied.

What is suspected?

The condition is a disease called Ash Decline in Arizona and caused by an MLO, a Mycoplasma like organism.

Because it is an MLO, it is thought to be spread by insects.

Infects ash trees with Arizona ash (Fraxinus velutina) genetics. Shamel ash (F. uhedi) is thought to be resistant. No trees other than those with F. velutina genetics has been infested.

What to do?

My recommendations are:

1. Remove ash trees showing symptoms after the dieback has been confirmed it is due to Ash Decline to prevent the spread of this condition.

2. Stop the planting of ash trees in the Las Vegas valley.

Bob Morris

To Remove or Not Remove Ash Trees with Dead Branches?

Q. I have been following your comments on ash tree decline. You believe those trees should be promptly removed.  Is this to contain the disease?

Does Ash Decline Exist? Something is causing the limbs to die and water and fertilizer dont change anything.


A. This disease is called Ash Tree Decline in Arizona and Ash Dieback in California. In California, ‘Raywood’ ash has been the hardest hit. In Arizona and Nevada ash trees like ‘Modesto’, ‘Raywood’, ‘Fan-Tex’, ‘Rio Grande’ and other ash trees having Arizona ash genetics have shown branch dieback and “failure to thrive” symptoms.


 We suspect it is an MLO and the "disease" is spread by "something" from tree to tree. Insects? Pruners? Cicada feeds on plant roots like this tree, climbs out of the ground onto the trunk and pupates (leaves its "skin" behind, cuts into trees with its ovipositor and lays its eggs. A possible culprit in its spread?

The disease itself is thought to be an MLO (Mycoplasma Like Organism). What we do know is that it’s probably transferred to new trees by insects, just like other MLO’s. So, my recommendation has been to contain the disease by removing potentially infected trees, so they don’t become a source of inoculum to other trees. If suspected trees receive more water and fertilizer but fail to grow, then we should assume it has Ash Decline until we know differently. I have not seen it on any other trees but relatives of Arizona ash.

Was Your Ocotillo Alive When You Bought It?

Q. I have tried to grow an ocotillo several times with little to no success. Please give me your input on watering and other care.

From the Sonoran Desert and very low water use (xeric), can easily handle rock mulch, but can take up to two years to see any results.


A. Buy and plant in the spring from February through April or in the fall from late September through mid-November. Make sure the Ocotillo is alive when you buy it from the nursery. The wood just below the surface should be green when scratched with your thumbnail even though there may be no leaves. The smaller canes should not snap when bent but be pliable.

Normally I dont care for information from vendors but this aint bad on Ocotillo from Miracle Gro!

            Contrary to some popular ideas, mix about 10% compost in the planting hole about 2 feet wide. The whole doesn’t have to be dug deep just deep enough to accommodate the roots. The compost mixed in the soil keeps the soil open, adds plant nutrients and beneficial microorganisms.

            Plant it the same depth it was growing in the container or in the wild. Use lots of water to settle the soil around the roots. The soil around it should be muddy when you’re finished. Construct a basin 2 to 3 inches deep around the plant. Immediately stake the plant to keep it from moving while the roots are growing. Staking may take one to two growing seasons.

            Water no more than once a week during the heat of the summer during its establishment by filling the basin with water. Water once a month in the winter. After it has been established for two or three growing seasons use four drip emitters placed about 12 inches from the plant. Fertilize it once a year in the early spring just before growth.

Spring Bouquet Viburnum is NOT a Desert Plant but You Can Grow It

Q. What’s happening to my Spring Bouquet (Viburnum tinus)?  It has bloomed beautifully in the Spring for several years (including this past Spring), but many of the leaves are turning brown, and appear to be burnt.  I didn’t see any evidence of spider mites or other pests.  I checked the drippers, and it is getting sufficient water.

A. Spring Bouquet is the marketing name given to the compact form of a flowering shrub found in the nursery trade in California. Technically this group of shrubs are called Laurustinus so let’s just call it Spring Bouquet viburnum. It’s gotten some tracking in the Mojave Desert mostly from people moving here from California. It’s not a desert plant but it comes from the dry Mediterranean area so think rosemary, oleander, Laurel, junipers, and cypresses like Italian Cypress. Like other Mediterranean plants it’s mesic in its water use so plant it in soil amended with compost and it may not like being surrounded by rock after a few years down the road. It grows best on the east or north side of a home. You will take more chances growing it on the south or west sides in a sunny location, but it may do okay in the shade of a tree during the hot afternoons and surrounded by other plants. It will not like rock on the soil surface as it gets older.

            Like other Mediterranean plants the biggest disease problems are root rots from watering too often or poor water drainage. Viburnum like yours gets aphids and thrips in the spring. In the heat of the summer, it may get spider mites and thrips damage may continue. So, you are right for checking or spider mites when summer temperatures arrive. If spider mites are problems the leaves appear dusty and oftentimes light webbing can be seen.

This webbing from spider mites (why do you think they are called spider...mites...?) on tomato but if they are spider...mites...then you will see webbing on your plant as well.


           
However, the usual problem is planting them in hot bright locations and then surrounding them with rock on the soil surface. The soil amendments last for a couple of years but they slowly dissolve into desert soil over the next 3 to 5 years and the plants start getting burnt edges around the leaves.

            Before buying an insecticide look at it at about 2 PM. Is the location where it’s planted hot and very sunny? Is the plant surrounded by rock on the soil surface? If the answer is yes to both of those questions, then it’s probably a location problem combined with a soil problem and not spider mites. Nurse it through the summer and in the fall rake back the rock, amend the soil with compost and cover as much of the area with woodchips as you can.

Try the paper test for detecting mites because they are so small

Rosemary for Oils and Cooking are Different

Q. I use rosemary in my cooking, which I purchase from the store.  It is expensive and it does not last very long if I don't use it all. I would like to plant a rosemary bush in our yard so that I can use it in my cooking as I please.  Is there a difference between rosemary bush used for "cooking" and regular rosemary used in landscaping?

Honeybees like Rosemary flowers and these plants flower all season long and particularly profuse in the winter. So put them where people are not afraid of bees.

A. Landscape rosemary works if you want a balance between visual appeal and cooking. Use the new growth that has the flowers if you want it for cooking. If you are serious about a type of rosemary used for cooking, then pick a variety recognized for its oil content.

Landscape rosemary focuses more on looks, green foliage and flower color, rather than oil content About as sophisticated as you can get with landscape rosemary is the difference between an “upright” and a spreading or “prostrate” form. If the new growth is pointing upward, it’s an “upright” form. If the new growth is growing more horizontally then it’s a spreading or “prostrate” form. The prostrate form is a good choice if you want it to cascade down or over a wall but not considered a strong form for cooking.

            Rosemary is a Mediterranean plant which means it likes dry and rocky soils found in southern Italy, Greece and Turkey, rock gardens, non-desert parts of California, but it’s not a cactus so it doesn’t like an unamended desert soil contrary to what the University of Florida tells you. When in doubt it’s always safe to amend desert soil a little bit when planting anything you are not sure about, even cactus.

The oil content in rosemary is what gives it the flavor you want for cooking. The most aromatic portion of the plant with the highest and best quality oil is the new growth containing new flowers. So, if your primary focus in having arosemary plant is cooking then focus on varieties of rosemary with high oil content such as ‘Benenden Blue’, ‘Flora Rosa’, ‘Tuscan Blue’, ‘Majorca Pink’, ‘Arp’, ‘Albiflorus’, ‘Huntington Carpet’, ‘McConnell's Blue’, ‘Irene’, ‘Holly Hyde’, and ‘Hill Hardy’ to name a few.

Rose of Sharon a Popular Las Vegas Plant 40 Years Ago

Q. I just saw Rose of Sharon (Hibiscus syriacus) for sale at a local nursery. It reminded me of a yard I saw over 40 years ago in the Huntridge area that had a row of these plants which were spectacular. I was wondering what your thoughts were on this plant in our climate.

I think this is a Rose of Sharon, aka shrub althaea. I only identified as a hibiscus and many of you know I have a farm in the Philippines and we have tropical hibiscus there. And now, the crazies are planting tropical hibiscus in LV?


A. Rose of Sharon is a hardy and fun deciduous shrub for our climate that grows about 10 feet tall and 4 to 6 feet wide and covered in large Hibiscus-like flowers all summer long. Keep in mind it should go into the mesic part of your yard because it is MESIC and not XERIC!!!!. It will not like rock much or unamended soil. But Rose of Sharon is hard to find from local nurseries. The flowers range in color from white to blue to purple to red depending on the variety. These shrubs are underappreciated in our climate. There is some great breeding work done on it at Texas A and M at the Vernon Center.

Plant this shrub in a bright north or east area in the Mojave Desert with compost amending the soil and wood chips as a surface mulch. It’s not meant to be planted in isolated areas all by itself or surrounded by rock. It likes companionship in areas with lots of light and wood chip mulch. It’s considered mesic in its water use and not meant for desert landscapes.

            It’s easy to propagate from no bigger than pencil-diameter sized cuttings about 8 to 12 inches long with the leaves removed and dipped in rooting hormone. Use potting soil in small containers as the propagation medium. Plant no later than early summer. If grown as a flowering hedge, put them 4 to 6 feet apart and irrigate the row with drip tubing instead of emitters. Propagating Rose of Sharon and other hibiscus.

Tuesday, May 25, 2021

Orchard, Fruit Tree and Grape Calendar for Las Vegas

My recommendations for a 12-month calendar of operations for a mixture of different fruits in the Las Vegas area. Harvest starts about mid to late May with early peaches like 'Earlitreat'. Harvesting ends in December with apple varieties like 'Sundowner'. There is a range because weather conditions vary from year to year; one year might be warmer earlier or later than another. That can affect the dates.

Important operations include pruning, fertilizer/iron applications, thinning, summer pruning, pest control, harvesting, dormant oil applications.

January 1-31. Second application of dormant oil on warm, windless day.

January 15-31. Weed control before new growth starts. Weekly weed control begins.

February 1. Fertilizer application to fruit trees plus iron EDDHA added through EZ flow. One application of fertilizer each year.

February 15. Watch for aphids on new growth.

February 15-28. Start soil applications of iron EDDHA on trees yellowing.

February 15-28. Thin apricots, early plums, peaches and nectarines.

February 15-28. Start thinning. 

February 15-28. Fertilizer applications for grapes.

March 1. Treat for borers on fruit trees that finished flowering.

March 1-15. Treat ant nests with bait.

April 1-15. All thinning of peaches, nectarines, plums and apricots should be finished.

April 1-15. Start thinning pears.

April 1-15. Start summer pruning.

April 1-15. Start thinning apples.

April 1-15. Pinch and remove excess/remaining grape bunches.

May 1. Watch for leaf footed plant bug, peach twig borer, codling moth, grape leaf skeletonizer.

May 1-15. Watch for Fireblight disease as it appears in Asian pear, European pear, apple and quince.

May 1-15. End soil iron applications.

May 10-20. Harvesting begins.

May 15-31. Begin foliar sprays of individual trees with iron for yellowing.

June 1. Watch for whiteflies.

June 1-15. Summer pruning ends.

September 15-30. Start harvesting early pomegranates and pears.

October 1-15. Turn off water to trees for early pruning to reduce height of trees. (Optional)

November 15-30. Start pruning. Pruning can be done anytime all winter.

December 1. Order bareroot fruit trees.

December 15-31. First application of dormant oil on warm, windless day.

December 15. Harvesting ends.

Harvesting Fruit Too Early Can Affect Flavor

Remember, stored fruit are ALIVE. They are still breathing (respiration) harvesting is done on climacteric fruit (peaches, nectarines, plums, apricots) when the fruit has changed color and lost most of its green color but still firm.

Climacteric fruit like these peaches are harvested when they have changed color but still firm. Harvesting climacteric fruit too early can result in poor flavor.

Harvesters are told not to wear jewelry, wear gloves, and have short fingernails when harvesting. These can also cause damage to fruit. After harvesting, fruit is sorted by maturity and fruit skin abrasions, bruising and punctures. Damaged fruit is NEVER stored with non damaged fruit due to the release of ethylene gas and speed of ripening through damage.


Damaged fruit like this sun damaged apple is never stored with undamaged fruit.

Nectarine damaged by thrips in the foreground. Damage is visual but too severe for the consumer. It is safe for storage but not suitable for sale.


 

Harvest Time in Las Vegas


Peaches and nectarines- variable but there is a loss of dark green and change to either light green, yellow or red but fruit is still firm (solid to the feel). Oftentimes a penetrometer is used to gauge this for establishing values by fruit buyers and wholesalers. https://www.youtube.com/watch?v=y1VyPTA7vU4 In the field it is done by feel.


Peach fruit ready for harvest. Firm enough for harvest and mature enough for harvest.


Plums – green plums when color change is from dark green to light green but fruit is still hard

Red plums when color change is from dark green to yellow or red and fruit is still hard.


Burbank plum firm, tree ripe and ready for harvest.


Pears – some are green and some are red. Harvest pears AS SOON AS COLOR CHANGES TO GET A “BUTTERY” TEXTURE OTHERWISE TEXTURE IS GRITTY. Same as plums.


Correct color change for harvesting European pear.


Asian pears - when fruit separates from the tree when lifted.


Asian pear, 'Shinko' ready for harvest. The fruit separates from the tree when lifted.


Apricots – change in color from dark to light green but still firm.


Apricots ready to pick. Fruit shows little difference in quality when harvested a little bit early. Apriums are treated the same as apricots.


Apples- near fully mature but still hard; this means color changes are important because what you harvest is what you get.


'Pink Lady' apples, like all apples, are harvested when the seed is brown or by calendar. They ripen in November in Las Vegas.


Quince – mildly climacteric with some improvement in maturity after picking. Pick when color changes and aroma begins.


Quince is harvested when the aroma from them is "floral" and, like apples, when the seeds are brown. I  put my nose directly in the bottom (calyx end) and take a deep smell. When they start to give off an aroma, they are ripe.


Pomegranate- by date or fully mature. Will store near freezing (colder than apples) for a long time.


Mature pomegranates will keep on the bush or tree for a month when they are ready. Harvest when fully ripe. Use a date for harvesting and know which variety you have.


Persimmon- some persimmon are astringent and others are not. Nonastringent persimmon can be harvested anytime after color change. Astringent persimmon MUST only be harvested when firm but near harvest but eaten when soft.


Harvest nonastringent persimmon like 'Fuyu' when there is a color change. Harvest astringent types like 'Hachiya' when it is firm but fully red. Astringent types must be soft to be eaten when they are sweet.


Grapes – nonclimacteric so harvested only when fully ripe; use refractometer. They will appear like they are ripe but they will still increase in sugar content. The clusters of wine grapes will have some "raisins" when ripe.


'Fantasy' dessert grape ready to harvest. Check sugar content with refractometer or taste.

'Zinfandel' wine grape harvest by refractometer or taste.


Figs - nonclimacteric harvested only when fully ripe, like berries. Look for the "neck" to bend.


All figs are nonclimacteric so harvest when ready to eat. Figs are ripe when the stalk attaching the fruit to the tree is bent.


Soft vs. Hard Fruit

Soft fruit is fruit that is soft when mature. These include peach, nectarine, plum, apricot, Soft fruit are harvested with smaller boxes, bags or containers that are not deep. Hard fruit like apples, pear, pomegranate, and quince are harder when mature. They are harvested in deeper bags, boxes and containers. 

Storage

Fruit that is fully mature when harvested will not store well and should be consumed ASAP and never stored. Harvesting of nonclimacteric fruit (grapes, figs, pomegranates, jujube) is done when the fruit is fully mature since it stops maturing as soon as it is picked.

 

Once fruit is harvested all fruit is sorted immediately (maturity and damage) and commercial fruit is graded and prepared for sale and storage. Maturity is less important for commercial sale.

 

Storage is a combination of temperature and humidity. CA storage (controlled atmosphere storage) is used to prolong storage life of some fruit and vegetables (along with correct temperature and humidity and sanitation). Nitrogen is substituted for oxygen.

 

The term climacteric is not an "on and off" switch and there are some fruit that are more climacteric than others (compare apples and pomegranates with peach, plum and apricot). Some fruit are “in between” and show signs to be both climacteric and nonclimacteric (apples, pomegranates which are still considered climacteric but not strongly climacteric but still releases ethylene gas).

 

Release of ethylene gas is why some fruit are stored separately. Build up of ethylene causes them to get an off taste and mature faster so apples, melons, apricots, bananas, tomatoes, avocados, peaches, pears, nectarines, plums, figs and other fruit and vegetables should be kept in separate cold storage rooms. These fruit are never stored with most flowers or the flowers die sooner. Some fruit can be stored with nitrogen gas (CA storage) to reduce respiration losses and longer storage life.  Some require much warmer storage temps (compare banana with pomegranate) for storage. Chlorine gas is used to “degreen” tomatoes and oranges in a “degreening room” because of the consumer and sales.

 

Physiological maturity is different for different fruits. But in most there is a change in color (loss of dark green to light green in green or yellow fruit and a gain of some color like red, brown.

 

From http://www.fao.org/3/ae075e/ae075e21.htm

Ripening

Ripening is the process by which fruits attain their desirable flavor, color and textural properties. Climacteric fruits can ripen off the plant once they have reached physiological maturity.

Climacteric fruits include apples, avocado, banana, blueberries, breadfruit, cherimoya, durian, feijoa, fig, guava, kiwifruit, mango, muskmelon, papaya, passion fruit, pears, persimmon, plantain, quince, sapodilla, sapote, soursop, stone fruits (apricots, nectarines, peaches, plums) and tomato. Some of these fruits if harvested "mature-green", can be ripened after harvest and short term storage. Pears and bananas are unusual in that they develop the best flavor and texture characteristics when harvested mature-green and ripened off the tree. Avocadoes do not ripen on the tree.

Some climacteric fruits give off large quantities of ethylene during ripening. These include apples, apricots, avocadoes, cantaloupe, kiwifruit, nectarines, peaches, pears, plums and passion fruit. A small dose of ethylene gas will stimulate other climacteric fruits to begin the ripening process. A few climacteric fruits, such as muskmelons, will not increase in sugar content during ripening, but will soften.

Non-climacteric fruits must ripen on the plant if you want a fully ripe fruit, since once they have been harvested, no further ripening will occur. Flavor and texture will be of low quality if fruits are picked before fully ripe.

Some non-climacteric fruits include berries, cherries, citrus fruits (lemons, limes, oranges, grapefruits, mandarins, tangerines), cucumber, dates, eggplant, grapes, lychee, okra, peas, peppers, pineapple, pomegranates, strawberry, summer squash, tamarillo and watermelon.

Non-climacteric fruits will not respond to attempts to ripen them with ethylene gas. A partially red strawberry, for example, will not develop any more color or sweetness after being picked, and will deteriorate faster if exposed to ethylene. Watermelons develop most of their sweetness during the week before they reach full maturity, making early harvest very undesirable.

Sometimes ripening commodities before sale at the wholesale or retail level will improve their value. Ripening rooms are often used for tomatoes, citrus fruits and bananas. The use of diluted ethylene gas mixtures is safer than using pure ethylene which is explosive and flammable at concentrations of 3% or higher.

 

Thinning Fruit to Make Remaining Fruit Larger

Thinning fruit must be done to get the remaining fruit larger. It's also done to prevent limb breakage from all the weight of mature fruit! Its best done as soon as possible, when fruit is still small. Usually when fruit is 1/2 inch or smaller. 

Peach fruit is thinned to allow the remaining fruit larger and prevent limb breakage. Usually only three or four fruit remain after thinning. How many fruit should be removed?

The same branch after thinning is done. Thinning can also be helped when pruning is done by making branches that are too long, shorter.

The fruit tree makes a set amount of “food” each year. It either goes into growth or fruit production. When thinning begins, the fruit should be small. If done when the fruit is larger then this “storage food” is removed from the tree and wasted. Thinning larger fruit and this green fruit is dropped to the ground takes the energy the tree invested into fruit production and puts it into the soil. Bugs are not a problem for the tree provided thinning is done early.

Apples and pears form fruit in clusters of typically five to six fruit. All but one is removed from each cluster. The remaining fruit was the largest in the cluster.

One fruit remains after thinning apples and pears. It is usually the largest in the cluster, the "king"


When thinning is done early the fruit can be dropped on the ground and left to rot. When thinning is done later and close to maturity, the fruit should be collected and not left to rot in the field or it will attract some damaging insects (eg stink bugs, fruit beetles, and fruit flies) and rodents.

 

Although it is thought that it is never too late to thin fruit, it is best done as early as possible. But if fruit is close to maturity, it is more attractive to pests that may go after ripe fruit in your orchard. Decomposers that focus on immature fruit is different from those that prefer mature fruit. Your trees also have mature fruit. So which mature fruit is okay for mature fruit decomposers to have?


Generally speaking, fruit thinning starts when the fruit is about ½ inch. For early producing varieties thinning is started early. For peaches growing in Las Vegas thinning can begin as early as the first week of March for the early flowering varieties and as late early May on later varieties.

  • Look for thinning to begin about March 1 on peaches and some varieties of apricots; later varieties are thinned later
  • Start to schedule thinning when fruit is about “thumbnail” size.
  • The timing for later varieties weekly as the fruit reaches this size. So I would suggest weekly thinning of fruit once it begins. Young apples may produce fruit for thinning until June or later!

 

Chemical sprays to thin fruit are available for professionals for apples and pears but peaches, nectarines and plums are done by hand.


June Drop


There is a term floating around for fruit trees called "June drop". June drop refers to the dropping of fruit by the tree if it is not pollinated correctly or if the tree decides there is too much fruit and drops some. This never happens in June but earlier, about April in our climate. It is said to "Thin after June drop." I have not seen this to be the case. I would suggest in our hot and variable desert climate to thin early and thin according to the variety you have. Ignore June drop. If you have lots of flowers, lots of fruit, then thin!


Fruit to Thin, Not to Thin, and Minor Fruit


Fruit and relatives of these fruit to thin include peach, nectarine, apricot, plum, pluots, apples, European pears, Asian pears. I have not seen any value to thinning pomegranate, fig, cherry, citrus, or jujube. But minor fruit you should consider thinning include persimmon and quince.


Grape Thinning

Grapes are thinned to make the remaining berries larger (desert grapes) or intensify the flavor (wine grapes). Thinning is done in three ways: spacing of bunches. reducing the size of bunches (pinching), and removing small bunches. Thinning is done when the berries are the size of baby peas.

Grapes are thinned when the berries are still small but after flowering.


 

http://www.omafra.gov.on.ca/english/crops/hort/thinning.htm

https://escholarship.org/content/qt2fg9r19k/qt2fg9r19k.pdf