Summer pruning focuses on removing or robbing the tree of its "invested" new growth. It can help keep tree smaller and reduce the pruning workload in the winter.
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| Summer pruning would control the size of this tree and reduce the pruning workload during the winter months. |
Q. I need a hedge to block the dog area from view. Are there any drought tolerant, full sun bushes that can handle extra nitrogen in the soil from the dog urine, or something I can add to the soil to balance that kind of nitrogen? I saw additives that claim to increase the beneficial microbes or bacteria or something like that to help the nitrogen cycle.
A. All plants are damaged if the urine from a dog (male or female) is in contact with any part of the plant. Water to dilute the urine or urea is what is normally recommended. You just have to catch it in time which means following the dog with a hose.
Generally, plant roots are more tender than the stems. Usually leaves of plants are about as tender as the roots. The plant grows back from damaged stems if dog urine is sprayed directly on the leaves or roots. Having soil around the roots makes them less susceptible when in direct contact with dog urine. How much less susceptible depends on the plants. But nearly all leaves are damaged. Stems will grow new leaves when damaged. Roots will grow new roots when damaged.
Any of the Texas Rangers will work (aka, Texas Sage). ‘Green Cloud’ or ‘Grey
Cloud’ varieties of Texas Rangers get about 10 feet tall and should be planted
no closer than 8 feet apart or 8 feet from a solid wall. There are shorter
varieties of Texas Rangers, like ‘Compacta’ (5’x5’ and 4 to 5 feet from a solid
wall) and ‘Cimmaron’ (3’x3’ and 2 to 3 feet from a solid wall) that use less
water because of their size and have a height more appropriate for some sites. They
are still Texas Rangers so how often they are irrigated is the same just give
them less water each time they are irrigated.
But there are two caveats. Remember ALL plants use water and the more plants of a larger size you have in your landscape, means it can cost more (in water or pumping costs) to irrigate them. The second caveat is that “people schedule when to water plants, plants don’t.” It begs the question, “Are plants responsible for water use or are people?” You can give low water use plants more water than they need, and they won’t care.
Be careful of marketing claims of
products. Sometimes they are correct and sometimes they stretch the truth. In
your case, I think you are talking about rejuvenating or renewing the soil
rather than the plant. Soil renewal is a totally different issue than plant
renewal. Protecting the soil won’t protect the plant from urine damage.
Do you want practice managing a plant that does not need much water by pruning it? Try this Sonoran Desert native plant, Jojoba, and see how you do. I was introduced to this plant in the mid-1980s when it was getting popular as a source of oil. It’s again popular but this time because it doesn’t use much water. Like most desert plants, it responds to watering by growing.
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| This was a picture of Jojoba taken by Andrea Meckley and posted on my blog in 2014. https://xtremehorticulture.blogspot.com/2014/09/desert-plants-jojoba.html |
You can read more about this plant here in a post by Andrea Meckley I published on this blog in 2014.
Growth of this plant is tied very closely to watering
frequency; 1 to 2 inches of water, 3 to 5 times each year. It has the
potential for saving water in the landscape if you know how to water and
prune it. Most fruit trees require about 50 inches of water each year. This
plant grows with 5 to 8 inches of applied water.
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| If you water it with your controller this is what you are likely to get. This is a jojoba on an irrigation timer. https://www.public.asu.edu/~camartin/plants/Plant%20html%20files/Irrigated%20jojoba.jpg |
· Unpruned height is nearly 20 feet tall. It grows this tall slowly. Height can be kept 5 to 6 feet tall if pruned once a year or every other year. Don't prune it from the top with a loppers or hedge shears. Get on your hands and knees and prune it with a loppers or hand shears at the base.
Can it
be grown taller and pruned into a small tree? Perhaps.
·
Evergreen plant unless it gets very cold (lower than 20F) and
then it drops its leaves and becomes deciduous. At very cold temperatures (below 15F) the
top of this plant may die to the ground.
·
Cold temperature limits: 20°F
·
High temperature limits: 125°F +
·
Irrigation: 5 to 8 inches of water each year. Give
it 1 to 2 inches of water in the spring, do that twice in the summer months and
once in the fall. Apply this water in a basin or donut surrounding the tree to
contain the water and reduce water waste. Do not put this plant on an existing
irrigation system or you will be sorry because of it’s growth.
·
Planting location: east side of a building or
wall is best but tolerates full sun (south or west sides) if planted at least 5
feet from a hot surface. Tolerates planting of rock mulch on the surface of the
soil.
· Spacing from each other or walls: depends on plants mature height. If grown 20 feet in height than planting distance is no closer than 15 feet apart (8 feet from a wall). If pruned to 6 feet height, then plant them no closer than force feet apart (2 feet from a wall).
Male and female plants are wind pollinated much like date palms and corn. If they are propagated by the nursery from seed, then you get 50-50 male and female unless there sexed. If plants are vegetatively propagated (no sex involved) then they will be either all-male or all-female if they came from the same plant. Male plants may cause a pollen problem. Female plants produce the fruit and oil. If these plants are watered too often or the soil has poor drainage, watering frequently on the controller may cause root problems, yellowing and plant death.
1. Pick
a location for planting, preferably on the east side of your home. The north
and south sides are okay as well but the east side is preferred. Pick a spot
that is at least half the distance from a wall equal to the height you want it
maintained at.
2. Plant
Jojoba (Simmondsia californica) without any drip or supplemental irrigation.
It’s okay to put it into a rock landscape. Build a level basin or donut around
the plant 4 feet in diameter that can hold 2 inches of water. When watering
with a hose, fill this basin or donut only once. Reestablish the irrigation basin
when it no longer holds enough water.
3. Make
the hole for it wide and the same depth as the container or roots. The roots of
this plant need places to spread horizontally easily.
4. Stake
the plant to establish the roots without wind for one growing season and then remove
the stake.
5. After
planting in the spring or fall, wet the soil thoroughly to remove air pockets
and establish the roots.
6. Fertilize
this shrub lightly once a year in the spring or fall or when needed.
7. Manage
this plant’s growth by watering its basin.
8. Prune
this plant at its base or bottom. Never prune this plant at its desired height.
Prune this plant from your knees. Prune this plant by removing long stems (usually 2-4) near its base (renewal or rejuvenation pruning).
Do not prune once a year. Usually not necessary unless it's being watered too often. Every two years, or whenever needed.
Check with your local nurseries and see if they haven't first. They usually have some sort of guarantee if it fails. Don't forget to check Lowes or Home Depot as well.
Online nurseries
California online native plant nursery, Las Pilitas
Arizona online nursery, Desert Horizon Nursery
Listing these online nurseries is not an endorsement of any specific nursery. I don't know them. It's just a suggestion.
Buying and planting citrus, subtropical and tropical trees, in the Eastern Mojave Desert can be a challenge. First is finding a good location then amending the soil, staking the tree and watering it. Learn how it is best done in this episode of Desert Horticulture.
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| Citrus selection can be tricky in the Las Vegas area due to our winter cold temperatures. Citrus with a think rind can indicate a potassium deficiency. Always use a citrus fertilizer once a year in the spring. |
Q. I am writing regarding the purchase and planting of a ‘Eureka’ lemon tree. Of main concern to me is where to plant the tree, where to purchase the tree, what sized tree should I purchase, how often should it be watered and fertilized, and how big should I make the planting hole?
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| Meyer lemon tree growing in a container in Las Vegas. |
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| Eureka lemon in Las Vegas |
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| Large unknown lemon grown in Lake Havasu, AZ. |
The rest of the information you
asked about is the same regardless of the variety. Depending on which variety
you want, you may have to purchase it from an online nursery. Select an average
sized tree, about 5 gallons in size, and plant it in the warmest microclimate you
can find surrounding your house (usually it’s on the south or west side). Amend
the soil with compost at planting time and dig the planting hole three times
the width of the roots. Plant it 8 to 5 feet from a warm wall and protect it
from the wind. Stake it for at least one year if it is a 5-gallon size or
larger. Plant wet. Cover the soil with woodchips when finished. Protect it from
rabbits.
Q. I'm finally having my empty backyard landscaped. It's the typical subdivision super hard "soil". Should it be amended somehow before the new plants are added? More than just in the hole where the plant goes, I mean.
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| Wet the soil first a few days before digging. Moist soil helps to make it softer. Mix compost with the soil taken from the hole by about 25 to 33%. |
A. Some of the landscape soils are hard, hard, hard! Wet the area to be planted with an hour of sprinkler water from a hose and sprinkler a few days before digging. This water will help make it softer to dig. I would recommend amending the soil in the planting hole with compost or another amendment a few days after it is wetted. Amend it between 25 to 33% with compost (one shovelful of compost to 3 or 4 shovelfuls of soil). The hole for the plant should be dug and amended to a width three times the size of the diameter of the container or roots. Then check it for drainage. The hole should drain water overnight. Wet amended soil should be at least chocolate brown in color.
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| Holes located where fruit trees are to be grown are wetted and amended with compost by about 25 to 33%. |
The hole does not have to be dug
deeper than the container but should be dug three times the root width of the
plants. Amend that soil taken from the hole. The only time the soil needs to be dug deeper than the container is
when the soil is very bad at draining water. If a planting hole is filled with
water and it drains this water overnight, then the drainage is good enough;
three times the width of the roots/container is enough soil preparation.
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| Younger trees are planted in wet, amended soil, covered in woodchips and staked to prevent them from blowing over in strong winds. |
If the water does not drain from the
hole overnight, you should plant on top of an embankment or a small hill. If
you are planting a medium sized shrub (6 to 10 feet tall) in this spot, then
the soil in the amended mound or hill should be 12 inches tall and about three
or four feet wide. If the tree or shrub is 20 feet tall then the soil mound should be 18 inches high. Cover this soil with a mulch of some sort, either woodchips
or rock depending on the type of plant.
Windy weather, like we had over a past weekend, is very damaging to plants. (Notice I said “is” and not “can be”?) Light winds cause very little damage. Moderate winds cause moderate amounts of damage. Strong winds cause lots of damage. Why? I can think of at least two reasons; extent of damage and water use.
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| Shallow rooting of tree because of annual flowers planted at its base. |
Vegetables grow the best when
located closest to the downwind side of a windbreak. Plants don’t care if the
windbreak is living or not, they just want the wind slowed. For this reason,
the best windbreaks are not solid walls (e.g., block walls) but perforated
walls (e.g., chain-link fence with slats inserted in them). Solid walls
cause the wind to swirl. Perforated walls cause the wind to slow. Science has
shown us the best windbreaks are about 80-90% solid, not 100% solid.
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| Windbreaks for orchard in a canyon |
Examples of damage include leaf and flower damage with small fruit ripped from the tree with some types of fruit trees. Plants grown in windy spots are smaller than plants grown in protected areas. In strong windy locations I have seen fruit trees that lean away from the wind. Wind damage to fruit trees is the worst on trees closest to the wind. Wind damage lessens on the second and third row of fruit trees. Plant fruit trees in blocks so they give each other wind protection. Locate fruit trees that tolerate wind damage the most on the windward side of the block. Examples of wind tolerant fruit trees are pomegranates, apples, and pears. These trees will protect the less wind tolerant fruit trees. Fruit trees less tolerant of wind include citrus, plums, apricots, and peaches.
Plants during windy weather use more water. If the winds are strong and continuous, they use more water! Wind is a strong predictor of plant water use. In fact, along with how bright the sun is shining it is one of the strongest predictors of plant water use.
Go outside in
the morning. Look at the weather. Is it bright and sunny with very few
clouds in the sky? Winds is a major predictor of high-water use. Look at the
trees. Are the leaves moving? Look at a flag flying on a flagpole. Is the flag
barely moving? Is the flag flapping a lot? Is the flag rippling because of the
wind? Those are indicators of wind strength. Bright, cloudless skies and strong
winds equals high water use in our desert climate. It’s time to water during
bright windy weather.
Q. Will a caper bush (Capparis spinosa) grow in Las Vegas? Where might I buy one? I called a local nursery and got nowhere.
A. Briny capers are the unripened flower buds from a wild
spiny plant that grows in the Mediterranean region and parts of Asia. Immature
flowers from these plants are dried and then put in a brine solution for
preservation. Their lemony, floral hints might remind you slightly of green
olives since they are added to food as a condiment.
The plants are usually started from seed but I’m sure some entrepreneurial online nursery grows them as plants to sell. They are about 3 feet tall and wider than they are tall since the stems tend to lay down if given a lot of water.
I have never tried to grow them in our climate. They have enough cold tolerance and they are Mediterranean. I would try it on the Eastern side of a building with soil improvement and additional water at the time of planting. I’m no expert but if this plant grows in the dry, hot Mediterranean region, it has a good chance of surviving our desert climate as well. The information I saw maintains they are good down to winter temperatures of about 20°F when they get older and larger. If temperatures get in the low 20s this plant suckers from its base. Think Bay Laurel, oleander, Italian Cypress, and you’ll get an idea of the climate and soils they like.
Q. I read somewhere that putting crushed up eggshells is good for the garden, so I have been doing that. I also throw tea leaves and coffee grounds on the garden which I know is good, but I was wondering about the eggshells. Are they helpful and I should continue or forget it and throw them out?
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| Eggs and bananas at our farm in Batangas, Philippines. Ground up eggshells are better chemically for the soil in out tropical, high rainfall soil than in the desert where there is plenty of calcium. Banana peels release more nutrients than the eggshells. |
A. They do two things; organics improve the structure and texture of the soil and add to its chemistry. Warm wet soil decomposes the smallest stuff first. Put eggshells and tea leaves in a blender with some water before composting or adding them to a soil. Coffee grounds are already “ground up” so it’s not necessary to use a blender.
Any kind of “organic” breaks down
in the soil through the action of organisms where it turns into “Black Gold”,
improving soil structure and slowly releasing the chemicals they contain. There
is a lot of information available on the chemicals released by eggshells, tea leaves and coffee grounds. But get them small if you want them to be released quicker. When adding stuff to the soil it is better to add a whole bunch of different stuff than just one thing like all eggshells or all banana peels.
Eggshells are mostly calcium, the same kind used to increase alkalinity in soil It is better for soils that are more acidic such as higher rainfall areas. But still eggshells are not bad for the soil.
Q. What do I do with all the partially used chemical fertilizers in my garage?
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| Chemical storage. |
A. Most mineral fertilizers can be applied as the fertilizer bag recommends. They dont go bad unless they get wet.
Some fertilizers that contain pesticides must be disposed of properly. If your fertilizer does contain a pesticide then ask me how to get rid of it. If permitted and you no longer want or need these types of
fertilizers, give them to your non-organic neighbors for application. It’s best
to use them up as normal applications rather than put them out as garbage.
The mineral
fertilizers considered “hazardous waste” usually have a weed killer or insecticide that is no
longer permitted to be applied by homeowners. These fertilizers should be
considered hazardous waste and disposed of according to county regulations that
are intended to protect our water supply. Other types of mineral fertilizers
can legally be applied. But ask to make sure.
Q. I want to replace all my chemical fertilizers with organic formulations. The problem is that I’m not finding any organic fertilizers for landscape trees and shrubs such as podocarpus and photinia. Is it possible to make my own? Please tell me what you recommend.
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| For the USDA National Organic Program find fertilizers that are OMRI Listed or Approved for the USDA NOP. Other countries, places and people have different definitions of "organic". |
A. The definition of “organic” can be difficult. To some
people organic means free from pesticides and mineral fertilizers. To others it’s
things like fish emulsion, kelp meal, bone meal guano, etc. To others it means
strict adherence to the USDA definition of organic. In the United States the
term organic usually means it’s a listed product of OMRI (Organic Materials
Review Institute) which recommends products for the USDA’s National Organic Program (NOP).
There
are fertilizers in bags listed as OMRI approved. I would look for the word
“Organic” mentioned somewhere on the bag. Technically, a product cannot mention
the word organic unless it’s recommended for USDA’s organic program. One that
comes to mind is the OMRI Listed fertilizer called, “All Purpose” manufactured
by Grow More. It resembles a mineral fertilizer when you open the bag but it’s
one of the “organic” types.
Q. I have an ornamental flowering plum that produces fruit. I want to spray it to stop the fruit production and the messiness it brings. Last year I had a commercial applicator apply it, but I think I want to save some money and do it myself this year.
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| This is ornamental (flowering) plum fruit. The fruit is harvested by many to make a very tart (lots of sugar) jam or jelly. Commercially it is available as a fruit tree called 'Sprite' and 'Delight'. |
A. Mark your calendar because yours will flower within the same week, plus or minus, every year. You’ll have to spray the tree with a chemical every year to get the fruit to drop when it’s still small and prevent the messiness later. To get it to work, spray the entire canopy of the tree when as many of the flowers are open as possible.
You will
find it under several different similar trade names like, “Olive Stop”, “Fruit
Eliminator”, “Fruit Be Gone”, or some similar name. What is important is the
active ingredient listed on the front label in small letters. The most common
active ingredient is Florel, but you might also find it listed as NAA,
Fruitone, etc.
This
concentrated spray is diluted with water and first sprayed when the flowers on
the tree are fully open 20 to 30%. For best results it is sprayed again at 80% of
full bloom a couple weeks later. Commercial applicators spray the tree a single
time when it’s close to full bloom. It’s a good idea to include a wetting agent
or surfactant before spraying to improve the sprays coverage and penetration.
It’s
important that the flowers are open and sprayed to the point where the inside
is wet, and the flower starts dripping when you’re finished. The canopy of the
tree is dripping with the spray when you’re done. This is called “to the point
of runoff”. Spraying the open flowers above their reach is the usual problem
for most homeowners because they don’t have a good way of spraying all the
flowers.
The
ornamental flowering plum is an actual fruit tree. Nothing wrong with the
fruit. It’s naturally “puckery”. Many people make jam and jelly with it when
the fruit is not sprayed. I would not recommend making jam or jelly with it if
it’s been sprayed. Add as much sugar to it as your taste permits.
Q. At our wildlife preserve near Midland, Texas, I found ephedra plants (Mormon tea) that looks like it might be diseased. Other plants in the area look fine. We are currently in a severe drought condition, but most ephedra clumps are flowering. Have any ideas?
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| Disease or drought? Give it to a pathologist and they will claim its a disease. Give it to a soil and water scientist and they will claim drought. Are they both right? Which came first, the chicken or the egg. |
A. Native plants like “Mormon tea” or ephedra will dieback when the soil gets dry for a long time. That;s their nature. Dying back is normal but it can be
confused with a disease, or it might be a disease causing it. Sometimes native
plants succumb to diseases when they are weakened and don’t receive enough
water. But don’t worry. They will spring back to life during the next rain.
Water in the soil is irregular in supply because of its
distribution and the soils capability of storing water. For this reason, some plants
receive more water than others just simply because of differences in soil
texture (variability in soil, various amounts of sand, silt, and clay). Because
of genetics some plants are more susceptible to disease than others.
If your
curiosity is bugging you, the way to find out which disease is to contact your
State Plant pathologist and send in a sample. But this may not give you an answer
you can apply but it may solve your curiosity. I'm guessing the State Plant
pathologist will confirm there is a disease present but it's probably one of
the less vigorous diseases like Cytospora spp. that affects weakened
various plants that are in the process of dying back due to a lack of water.
Instead
of sending it to the pathologist I would take a couple of gallons of water and
pour about a quart to 2 quarts of this water at the base of several of the
“diseased” plants and watch what happens. Reaction by the plant might take two
weeks in warm weather. You may see some new growth at the base of the plant in
a week or two. Then again, you might not. It depends on what you want to learn;
is there a disease present? Or do you want to solve the potential disease problem?
Q. My African sumac tree has a fungus in it. I am thinking of cutting off the whole main branch because of the disease but it’s a guide branch and I hate to do that. Or can I just cut off the branch that broke? Any info you have would be greatly appreciated!
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| Bottom picture is limb of African Sumac reportedly dead. The top picture is the inside of the limb cut open to show the dead part inside. |
A. The disease won’t spread to healthy parts of the plant.
The rot or disease spreads internally inside the tree because it's what we call
"saprophytic" and only attacks dead or very weak wood. There is
nothing you can do to stop it.
The
center of the tree is composed of dead wood. The only living part of the tree
is a thin ring just under the bark. This living part is strong enough to stop
the spread of this "saprophytic" disease. The only thing you can do
to help your tree is to make sure that whatever you use to cut or prune the
wood is as clean and sharp as possible.
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| Narrow crotch angles are not good in landscape trees. They are shaped like the letter "V". After time they start to split as their weight increases and rot can begin on the inside of the trunk. |
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| Narrow crotches start to split during the wind and its internal dead wood begins to rot. This rotting will not affect the living parts of the tree. Only the dead parts. |
My guess is that this “rot” started at the top of a narrow crotch; where two limbs come together. Narrow crotch is making the letter V when you look at it. Week crotches can split in strong winds particularly if the inside of the tree has been starting to rot there. A strong crotch angle makes the letter “U” and less likely to start rotting in that spot and then split apart in strong winds.
Prune it enough to shape the tree the way you
want it. Just cut off the branch that broke very close to the next larger
branch and let it heal and completely close it off in three or four years. It
takes longer to heal if it’s not cut close to the trunk so there is no longer a
stub remaining. If the tree looks healthy to you otherwise then don’t worry
about it. Cut off the limb close to the trunk with a clean blade.
I think it was the cleric and economist Robert Malthus who developed a theory that large populations of organisms would slowly make their own environment more "toxic" and no longer sustain themselves. In some ways what he observed is true. We are living in an environment that is becoming more "toxic" as we grow our own food. Some of these "toxicities" come from industrial processes and some of them from our own efforts.
Our worlds are becoming more and more toxic. A few states in the US have posted the level of toxicity in fertilizers for home gardens. There has been lots of research on this topic. Brochures exist on heavy metals and gardens. And here. These toxicities are below what the US EPA considers "safe" for human health but they do exist.
Another problem with additions to garden soils are the levels of pharmaceuticals used when producing gardens soils and compost.
This is from the Washington State Department of Agriculture website
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| Because pepper tress are usually evergreen during warm winters in southern Nevada they will drop their leaves all season long. |
A. California pepper tree is a better selection than
Brazilian pepper. But they are both evergreen and can pose a problem near water
that you want to keep clean. Evergreen plants constantly drop leaves all season
long but drop their leaves heaviest soon after times of new growth. A deciduous
tree that drops its leaves for the winter months is a better choice near pools
because you clean the pool only once.
Read more about pepper trees here
Make
sure it’s not dropping leaves because of a lack of water. Increase the amount
of water and the frequency of application to make sure it’s not dropping its
leaves because the soil is too dry. The recommended frequency of water application
by water purveyors is correct for mesic trees growing in landscapes. Check to
make sure enough water is applied each time to penetrate the soil 18 to 24
inches deep. Make sure that water is applied to at least half the area
under the tree canopy. Water again when the soil at 8 to 10 inches deep is
about half full of water or starting to dry out. To reduce soil evaporation and
we growth, apply a surface mulch of rock or woodchips to a depth of 2 to 3
inches.
Also
remember to apply water on, or just before, windy days. Use your weather app on
your phone to judge when it will be windy in the future.
You’re right
in that lowering the trees height decreases the amount of leaves and stems you must
clean up, but evergreen trees are still going to drop leaves at inconvenient
times of the year. If you decide to lower the trees height rather than replace
the trees, then pay the extra expense to have it done correctly by a licensed
arborist. Not all licensed arborists are good at pruning trees. See some
examples of their work before you employ them.
