Discussion about Soil Amendments for Vegans

Swarms of Little Black Bugs Attack Plants

Q. A few days ago my rose bushes were swarmed with small black (iridescent) flying beetles and they've cleaned out most of my roses. They also wiped out my one strawberry plant.

Flea beetle ataxic grape leaves leaving holes

Flea beetles aren't very large but they are small, black and iridescent

If enough of them come through this is the kind of damage they can do in a short time

A. I have not seen them but flea beetles come to mind this time of year. They are small, black and iridescent. This is the time of year they are normally active as well again in the fall.

They normally come in large swarms devouring a lot of soft leaves including roses, strawberries, grapes to name a few.

In about two weeks they will be gone as quickly as they appeared. The plants will grow back. I would not recommend anything to spray but simply wait until they are gone then give the plants a deep watering and fertilizer so they recover quickly.

Spring Rain Can Bring Several Problems to Landscapes

The rain this past weekend may have brought some problems along with it, the same as it did last year after a rain like this. Problems might develop during the coming week or, with some plants, even extend into May or later.

Japanese euonymous with powdery mildew

Plants like roses may show signs of powdery mildew disease. This disease is aggravated by cool, wet weather, splashing rain, followed by warm weather. It appears as a white powdery dust on the leaves that can kill them. This disease is usually weak in our climate mostly because of our low humidity and cloudless days.

Rose with powdery mildew

Pull off a few leaves so air can circulate through the plants and allow them dry out naturally. Apply a preventive spray of a conventional fungicide for roses, sulfur dust or Neem oil. Lower humidity, air movement and sunlight in the coming days may clear up this problem without pesticides on some plants.

Fire blight in pear

            Another problem on European and Asian pear as well as some apples is fire blight. This disease is particularly virulent too many members of the Rose family such as many of our fruit trees.

If these trees were flowering during this rain it is possible this disease may show its ugly head toward the beginning of May. Look for jet black dieback on new growth, usually very close to the infected flowers.

Classic symptoms of fire blight in pear

Cut out these stems or branches 12 inches below the infection and sterilize pruning tools after each cut. Bag these infected plant parts and get them off of your property.

Pomegranate disease due to wet spring weather

            Pomegranates that are flowering may develop fruit with a black interior later in the season. This disease can be the result of wet weather when they are flowering. This disease may not appear on fruit until quite a bit later in the season. It does not spread beyond the fruit and the fruit is inedible.

Mushrooms popping up in wood mulch after rain

            Mushrooms frequently pop out of the ground after a rain like this. Nothing to worry about but knock them over with a rake and keep them away from your pets. They are feeding off of decaying wood or wood chips in the soil or on the soil surface. They are good guys.

How to Care for Lilacs in the Desert

Q. My lilacs have bloomed and the flowers are gone. Is now the time to prune or do nothing? How do you prune or care for the lilacs.

Lilac planted in rock mulch with brown scorched leaves

Shrub pruned with heading cuts close to the ground

A. Most people don't know that low-chill varieties of common lilac will grow here as well as the Persian lilacs. Plant them in plenty of sunlight but in places which avoid the hot afternoon sun. All lilacs must be planted in a composted soil with a wood chip mulch. Rock mulch will not work.

Low-chill varieties do not need as much low temperatures to produce flowers. Lilacs that are not low chill will not produce as many flowers in our warm winter climate. Some plants require long periods of time when temperatures are cold so that flowers will be produced the next year.

Persian lilac may be a better choice for our climate and in smaller yards than common lilac. Persian lilacs are smaller in stature than common lilac, with smaller flower clusters and a lower winter chill requirement.

Hopefully local nurseries and garden centers that sell lilacs for our climate are selecting low-chill types such as an old time favorite here called "Lavender Lady". I believe this, along with "Angel White" were the first low chill lilacs available that would grow in the desert Southwest. Many of these low-chill varieties are referred to as the “Descanso Hybrids”.

Lilacs are not desert plants so they require lots of compost mixed in the soil at the time of planting with the soil covered in wood chips that decay over time. They should not be in rock mulch.

A very nice article appeared in Sunset Magazine and you can read it here http://www.sunset.com/garden/flowers-plants/mild-climate-lilacs

As with any seasonal flowering shrub or tree the best time to prune them is soon after flowering. If pruned later than this, the flowers for next year may not be produced.

First, remove the dead flowers before they form seeds by cutting them off at the base. Next, if needed, cut back branches or stems.

To increase the number of flowers you should increase the number of new branches it produces. Use a "heading cut". This type of cut is made somewhere along the length of the branch, usually just above a leaf on the outside of the branch.

Heading cuts grow three or four new shoots for every one that is cut that is made. This is an excellent way to make a shrub denser with more flowers.

If the shrub is getting too large, remove one third of all the longest stems back to within a couple of inches above ground. New stems will grow from just below these cuts.

A radical way of pruning this plant is to totally cut it off just above the soil surface. With plenty of water and some fertilizer new shoots will grow from these very short stubs resulting in an all-new plant. This is pretty radical but if the plant is overgrown with lots of wood showing, this may be your only alternative.

Remember, after pruning give it plenty of water and fertilize it with an all-purpose fertilizer.

Bottlebrush Several Reasons for Yellowing

Q. Two out of my 3 bottle brush bushes look dry and yellowish. The first 2 years they were fine. Does it mean they are not watered enough?

Bottlebrush flowering

Bottlebrush after Winter cold damage

Bottlebrush with yellowing due to iron chlorosis

A. Many plants in general, including bottlebrush, can be damaged if watered either too often or not watered frequently enough. If you are going to error about watering, it is better to give plants too much water than water them too often. But I think the problems iron, not water.

Right now water plants like this once or maybe twice each week at the most. Yellowing of the leaves can also happen because of real low winter temperatures. Similarly, it can also happen if the soil is not improved or covered in rock mulch.

Bottlebrush don't like rock mulch at all and if they are planted in rock mulch they frequently turn yellow in 3 to 5 years. If they get yellow enough, the leaves begin to turn brown and scorch. This is what I think happened to your plants.

Purchase an iron fertilizer and apply it to the soil above the roots now and water it in. The best iron fertilizer contains the letters EDDHA on the label or in the ingredients. EDDHA iron chelate is an important for iron product to use in desert soils.

Iron applied to the soil will only improve the green color of new growth. The older leaves which are yellow can only be improved with an iron fertilizer solution sprayed on the leaves. Spray this solution in one week intervals until you get a dark green color.

If these are growing in rock mulch, buy good quality compost, not a soil mix, and spread it around each of the plants and water it in. Apply around one to one half cubic foot of compost to the base of these plants and water it in, even in rock mulch.

Grapeleaf Skeletonizer Reported Flying Now in Las Vegas

A friend reported she saw the adult grapeleaf skeletonizer flying around her grapes in the Summerlin area of Las Vegas. You should begin looking for the adult which is a nearly black, unusual-looking moth near grapes.

Adult will lay eggs on the UNDERSIDES of leaves so you must look on the bottoms.

The young, larvae, are small "worms" that hatch from the eggs in about 7 to 10 days. This young worm stage is when they are most easy to control with sprays even insecticidal soaps.

Use sprays like Bt, Spinosad, insecticidal soap, .....Sevin, and general fruit tree insect sprays if you garden conventionally.

Visit these posts for more information

http://xtremehorticulture.blogspot.com/2015/04/leafhoppers-hornworm-and-skeletonizer.html

http://xtremehorticulture.blogspot.com/2013/05/watch-for-grape-leaves-disappearing.html

http://xtremehorticulture.blogspot.com/2013/05/update-on-grape-leaf-skeletonizer-from.html

Chinaberry Wind Damage

Q. Our Chinaberry tree broke off after the winds a few days ago. I saw all this dark wood inside the tree and it was dried out. This tree has withstood way stronger winds than what we just had which concerns me. Is this anything to be concerned about?

A. The inside of any tree, including Chinaberry or Texas Umbrella tree, is virtually dead regardless whether it is healthy or not. This dead area is called the “heartwood” of the tree. The only living part of its trunk is a small cylinder of wood surrounding the heartwood and just under the bark. This is called the “sapwood”.

Heartwood is darker in color than sapwood. Because it is dead, heartwood can rot without damaging the sapwood. This rotting of the heartwood can leave the tree hollow on the inside. But rotting of the heartwood can also make the tree weaker and prone to breakage during strong winds.

As a tree gets bigger it grows in two ways; it grows taller and limbs become longer called primary growth. It also gets "fatter" or bigger in diameter. This growth is called secondary growth. Secondary growth is responsible for sapwood remaining just under the bark as the tree gets “fatter”. As sapwood grows outward it leaves behind the dead heartwood in its interior.

The tree can live without its heartwood but it cannot live without its sapwood. But loss of heartwood can leave the tree weakened. If the tree can cause damage when it breaks, then consider removing it.

 The “dryness” of the wood may be "dry rot" as the heartwood is disappearing or rotting away. Frequently interior rotting of the tree is accompanied by soft growths attached to the trunk. These are a type of mushroom called “bracket fungi” or conks and are strong indicators that some form of rotting is occurring.

If you want to keep the tree strong, make sure it receives enough water and fertilize it once a year. If it does not, the tree becomes weaker and much easier to damage during strong winds.  

Fairy Duster Doesn't Need Water Often

Q. I put a Baja fairy duster plant in the ground about two months ago in a spot that gets full sun. It's not on a drip system but I deep water by hand every week. The leaves are turning light green. Is this normal for growth or am I watering too often?

A. Baja fairy duster is a beautiful little desert plant native to the Baja area of California and Mexico. It grows receiving water infrequently. It grows bigger if it is given a little extra water and fertilizer. But not too often or there can be problems.

I see from the picture you sent that this plant has wood chip mulch surrounding it on the soil surface. Wood chips are good idea but they help preserve water in the soil. This can result in too much water.

Don't let the wood mulch come in contact with the stems of this plant or it could cause the stems to rot. Keep it away from the stems by at least 6 inches.

Back off a bit on how often you water. It originates from Baja and gets very infrequent water so it will do well if watered every couple of weeks deeply. Fertilize it once or twice a year during late winter and just before flowering.

The other reason for yellowing can be lack of nitrogen so fertilize it lightly with a "flower fertilizer".

Grapefruit No Fruit

Q. I have an Oroblanco mini grapefruit along with other citrus growing in my backyard. All of them have flowered and set fruit except for this grapefruit. My friend has one of these too and hers has given her fruit. What do I do to get this finiky grapefruit to produce fruit?

A. If your backyard does not get too cold then it should produce well for you. Citrus biggest problem here is winter cold damage, freezing back and late spring frosts that eliminate flowers and fruit.

Grapefruit is one of the citrus that has the best potential for Las Vegas but Oroblanco is a grapefruit and pomello cross. It may be a bit more sensitive to winter cold and late freezes than traditional grapefruit like Marsh or Ruby Red.  

Oroblanco is harvested in the fall when temperatures are dropping around October. It is this time it has its best color and flavor.

It flowers in the spring. The tree should be loaded with flowers if there have been no freezing temperatures. About 2% of all the flowers will result in fruit. The rest of the flowers and young fruit are aborted by the tree.

The flowers give way to fruit as long as freezing temperatures don’t kill the flowers or young fruit during spring months. Flowers and young fruit are extremely sensitive to any freezing temperatures while the tree itself is much more tolerant. The flowers or flower buds will be killed but you may see no damage to the tree.

The other possibility is spring pruning. Citrus in general are seldom pruned unless it is needed. Excessive pruning in the spring can remove spring flowers before they come out. Pruning can also result in no flowers and no fruit. It is best to prune these trees just after harvest in October.

Irregular watering can cause the tree to drop flowers and fruit. Use a surface wood chip mulch to help keep the soil moisture from fluctuating too much and fruit/flower drop.

Pahrump Farmers Market

If you are not aware of it, Pahrump, Nevaada, has its own Farmers Market by local gardeners.
Please let others know about it. Send some pictures!

Where is it? What are the times?

Hours change 8:30-12 noon on the first Saturday in May.

Tied Palm Should Pop On Its Own

Q. How long do you keep fronds tied up after planting Mexican fan palms?                                            

A.  When large palm trees are delivered to a property for planting, frequently the fronds are gathered together and tied up in a bunch at the top. If they are wrapped correctly the fronds will bust open these ties as it pushes new growth.

If it is wrapped incorrectly they may have to be cut but this is seldom. It has been cool. Give it more time and wait to see if it does it on its own.

Otherwise cutting the ties can be done any time after planting. The purpose of tying them is to make the tree easier to load and transport on a truck, unload and plant. This decreases damage to the fronds during transport and planting.

Providence Community Garden Moves and Has Space Available

Do you know what a community garden is? A community garden is a plot of land set aside so that community members can garden together. Typically smaller areas or raised beds in this plot of land are "rented" to members of the community. Here they share their wisdom, their successes and their failures with each other. In my experience with community gardens about 40 % of the motivation is about gardening and a 60% is social and sharing.

Providence Community Garden

Providence Community Garden

Providence Community Garden

A very successful community garden in Las Vegas is the Providence Community Garden located near Jones and Oakey. They moved recently from the Jones and Decatur location. They have several raised beds available for local gardeners. Master Gardeners from the local Cooperative Extension are assisting in this project.

No previous gardening experience is required. You would learn a lot regarding their from people who have been gardening in our hot desert climate for decades. For more information contact one of their group at staheli51@gmail.com or bannock@cox.net. 

Yellow Leaf Drop on Some Trees Can Be Normal

Q. My evergreen oak tree is over 20 years old. Some of the leaves are turning yellow and dropping while there is some new growth, but not as vigorous as prior years. It is on drip and gets a deep watering twice a month. There is five-foot circle underneath with no rock. It also was deep root fertilized in February by a commercial company.

Yellow leaf drop can be normal on evergreen trees

A. If the yellowing and leaf drop is from older growth and not excessive it is probably normal. Evergreen trees like southern live or holly oak display leaf drop starting in the spring at the same time as new growth.

As new growth develops, older leaves begin to drop. All evergreen trees, including pine trees, show leaf or needle drop of the older ones and retain the younger ones until they also become too old and drop.

Pine needle drop can be normal as it drops older needles as new ones develop

The tree wants its young growth in the sun since it is more efficient at gathering light. The older growth is in the shade and is less efficient at gathering light. Leaves growing in the shade can be a detriment to the tree. They may consume more than they produce.

It is in the tree’s best interest to drop older leaves. If leaf drop is occurring on new growth then I would be more concerned.

On another note, as trees get larger they require more water. A sign the tree is not getting enough water is a lack of vigorous growth. You might consider adding more drip emitters to the tree so that it waters a larger area if you believe it is not getting enough water.

What? No apricot fruit?

Q. I have Katy and Blenheim apricots that are supposed to be low chill and self-pollinating but they barely produced any fruit the last two years. Three years ago both trees had a large amount of fruit. The trees seem to be healthy and there were plenty of bees.

A. Both of these types of apricots are older varieties and excellent producers in our climate. They are both self-pollinating and do not require much winter chilling temperatures to produce fruit.

Fruits of Katy apricot great for drying

You didn’t tell me if you saw flowers or not. The presence of flowers and no fruit is a big clue as to what may have happened. I am guessing you had lots of flowers but no fruit.

My guess is it was due to freezing temperatures during February. Apricots will flower during the first couple weeks of February. Last year there was a late freeze that could have eliminated apricot fruits in parts of the Valley where cold temperatures accumulate.

Apricot fruiting spurs

When fruit trees are near flowering, in flower or they have set small fruit, then these fruit buds/flowers/small fruit will tolerate temperatures from 32 to about 30° F. Nothing lower than this.

Too much shade from neighboring trees can eliminate fruit production in all but the sunny locations of the tree, usually hear the top or exposed sides.

You didn't mention pruning. If anyone pruned these trees and removed small side shoots from branches then there will be no fruit. Fruiting spurs are small side shoots going from branches. Fruiting spurs are needed on apricot for fruit production.

So unless someone pruned out the fruiting spurs or there was a late freeze this year, you should have plenty of apricots.

Ash Roots Can Be Removed with Care

Q. I have a 15-year-old ash tree in my backyard and roots are pushing up the brick walkway. Would it hurt the tree if I took up the brick and cut the roots off before they grow under the brick? The walkway is about six feet from the tree.

A. It shouldn't be a problem that far from the tree but let me tell you how I make that determination.

I look at where water is being applied to the tree. Tree roots will grow toward water. They will grow more aggressively where there is more water and fertilizer. They grow less aggressively in and toward dry areas.

Roots of fan tex ash

At a distance of 6 feet away from the trunk there should be no problem at all unless it is getting all of its water mostly from the area where roots are being cut. If tree roots are getting water from multiple locations then there should be no problem at all if you remove these roots.

Roots of ash surfacing in a lawn

Cut the roots in that area which are growing to a depth of 12 inches. After cutting them, sanitize the cut ends of any large roots that have been cut with soap and water. Let the cut ends of the roots dry and heal for a couple of days before putting soil back around them. There are some plant diseases present in soils that can enter the tree through open wounds. Sanitizing the cut ends and letting them heal first helps prevent these diseases from entering the tree.

Backfilling around the cut ends of roots while cuts are still fresh can increase the likelihood of disease problems.

Brown Center of Pampas Grass Common

Q. A few weeks ago I cut my ornamental pampas grass down, removing all last year’s dead growth. As the new growth is starting, I noticed a peculiar brown, circular pattern in the center that hasn't happened in the past. The new growth is coming along fine; nice and green, and a couple inches taller. Just nothing in the center.

Brown Center of pruned pampas grass

A. This brown center is common to many ornamental grasses as they get older. When the plant is very young and juvenile the entire plant is green, even the center.

As these plants get larger, they grow from outside shoots, or tillers, that make the plant larger in diameter. Each year this clump of grass gets larger and larger with the brown interior getting larger as well.

When these ornamental grasses get larger, the entire clump is dug up and divided into several smaller clumps. This propagation technique is called “division”. The brown portion of the plant is removed and the smaller plants are replanted or containerized and sold as a juvenile plants.

However, the new growth of your plant will cover up the dead interior and I don't think you will notice it anymore until you cut back again. 

Whitewash Not Meant for Stopping Rabbits

Q. I planted a couple of fruit trees and a visitor started chewing on it a bit, possibly a baby rabbit.  What should I treat it with or should I just paint it now with whitewash such as a 50/50 mixture of latex paint and water? I read this mixture stops rabbits from chewing on them.

A. I would strongly suggest you protect these trees from rabbits by putting a 2 foot tall cylinder of 1 inch hexagonal chicken wire around the outside of the tree. This excludes rabbits from chewing on the trunks.

A cylinder of 1 inch hexagon all chicken wire surrounding a new fruit tree to protect it from rabbit damage

Once the trunks get about 3 inches in diameter rabbits will no longer bother them and it can be removed. Be sure to bury the bottom edge of this cylinder one or 2 inches into the soil.

I don’t know if whitewash will prevent rabbit damage. The major reason for applying whitewash is to help prevent sunburn to the trunk and limbs of young, and even older fruit trees susceptible to sunburn. Fruit trees particularly susceptible are peach and nectarine.

Whitewashing the trunk and large limbs of an older fruit tree

 Whitewash years ago was made from a mixture of lime and water. Now most commercial whitewash is made from diluted white latex paint. I recently purchased some commercial, ready to use whitewash and I still found it needed more diluting with water.

You want a mixture of water and latex paint that changes the color of the bark from brown to a very light color. This better reflects sunlight and reduces damage from sunburn.

I have never heard of it used to deter rabbits so in my opinion it is strictly folklore unless it can be validated by others. There is a lot of anecdotal information floating around out there that is not very accurate but simply passed on without any proof.

Spraying Oil on New Fruit Trees Not a Bad Idea

Q. Should you spray fruit trees with horticultural oil if you are planting them for the first time?

New bare root fruit tree ready for planting

A. Horticultural oils are made from refined mineral oil and used during cooler times of the year to smother insects that might cause problems to a number of different plants. Even though horticultural oils are “natural” they are considered an insecticide since they kill insects by “smothering” them. They are most effective on aphids, scale insects, whiteflies and spider mites.

Horticultural oils are indiscriminate killers of insects, similar in that regard to soaps used as insecticides. They are indiscriminate because they kill any insect, bad or good, that is sprayed. But these types of sprays are safer to apply and for the environment than most conventional insecticides.

Aphids causing leaf curling and stickiness on Plum

No, you don't need to spray newly planted trees with horticultural oil when planting them unless you think they were infested when you bought them. However, it is not a bad idea and probably a good safety precaution since these trees are coming from places where there are usually a lot of new insects that can be brought into your garden.

Heavenly Bamboo/Nandina Yellowing and What to Do

Q. I noticed all my Nandinas, also called heavenly bamboo, are turning bright yellow. Is this a fungal disease problem? I'm worried that whatever this is will spread to all the other plants.

A. No, it is not caused by a disease organism. This is severe iron chlorosis and fairly common to heavenly bamboo growing in alkaline and desert soils.

Leaf yellowing happens frequently because of a lack in organic matter in the soil, increasing alkalinity or soil pH. I see heavenly bamboo planted with rock mulch and this yellowing frequently becomes a problem in a few years after planting in these situations.

Heavenly bamboo and rock mulch and yellowing

Start a program of soil enrichment and add a good quality iron product to the soil now as new growth is appearing. If there is rock mulch present, remember this type of mulch is probably adding to the problem. Plants like Nandina do not like rock mulch but grow healthier in a wood mulch environment.

Personally, I prefer iron EDDHA chelate as the source of iron to apply to the soil. It is a dry powder and must be watered into the soil accompanied by a good quality fertilizer.

Iron does not move from the soil into leaves that are already yellow. Iron applied to the soil only affects new growth and new leaves. The only way to improve the green color of existing yellow foliage is to apply iron fertilizers as a foliar spray.

Use any of the iron foliar fertilizers (liquids or powders that are mixed with water to make a liquid) and sprayed on the leaves. Sometimes it can take three or four applications, a week apart, to get them to green up adequately. Some plants green up with a single application.

The water used when spraying liquid iron should be distilled water. If using tap water, adjust the pH of the water to 7.0. When making applications to leaves always use a wetting agent such as EZ Wet.

You can also improve the new foliage to dark green by pruning them back, close to the ground, and letting them regrow after you apply iron EDDHA, compost, water and a fertilizer.

Desert Spoon For Desert Landscaping