Sorry, but “Ask Me Anything” has been canceled because there have been too many trolls.
In my Hot Gardens newsletter in the winter of 2006 I suggested that my online gardening friends do just 2 things for the new year: 1) plant a tree and 2) change one lightbulb to LED.
The large Fan Tex Ash tree thrives i hot dry climates and has gorgeous golden leaves in Fall.
Asking people to change light bulbs seems terribly out of date now–everyone has already done it. But planting a tree in your own garden is as smart and timely now as it was then. Especially since many ads about tree planting around the world and the U.S. are, as I have recently learned, somewhat misleading.
Deceptive ads about tree planting
We’ve all seen the ads telling us that Nepal or Ethiopia or some other country or a mega-international company has planted millions of trees.
And those claims of tree-planting are true and so inspirational!
But the ads tell only part of the story. As it turns out, some uncounted number of these millions of trees are being planted in ‘tree plantations’ and will be harvested in 10 to 20 years.
In a tree plantation there is no attempt to restore a natural forest which is more complicated than just sticking little trees in the ground lined up in neat rows. Trees in a plantation create a monoculture, rather than a diversified ecosystem. Each tree is like the next one all spaced for optimum growth with no smaller trees or shrubs in between. That means in 10 to 20 years when these more mature trees are cut down and hauled away the benefits of the trees will revert back to zero. Tree plantations are a short-term fix to a long term problem of rapidly increasing carbon dioxide in the air and climate change.
When most other plants are wearing summer green, the Crape myrtle bursts into colorful bloom. In dry climates it is a relatively small tree.
So I urge you to plant a tree or a few trees or long-lived shrubs in your garden in 2020. Become part of a long-term solution.
In recent weeks TV weathercasters in the desert Southwest have been laughingly referring to the “non-soon” as the annual summer rains got held up in West Texas. And, to make it worse, even fewer clouds came out of the Sea of Cortez. No rainstorms from either direction. Finally in late July one storm dropped enough rain to begin bringing Texas Rangers (Leucophyllum fructescens) into bloom.
Since then even record setting temperatures have not slowed the rush to flowering by these heat loving shrubs, native to the Chihuahua desert. They are a visual joy in blue, purple, lavender, and white!
Thanks to Starbucks in Marana AZ this Texas Ranger has been left untrimmed, although perhaps with too much shade on the plant. It prefers full sun.
Better yet, as SW natives the Texas Ranger thrives in very alkaline soil of .8 to .9 pH. While these 8 foot to 10 foot tall shrubs bloom in concert with the monsoon, they prefer fast draining soil to keep their roots almost dry so be sure to add plenty of organic material when you plant a Texas Ranger. And only irrigate them–lightly, if at all–during the summer months. Stop watering at the end of the monsoon in late September. And as for fertilizer? None needed at all. Fertilizer makes them spindly and weak.
NOW FOR MY RANT: Do not trim Texas Rangers into lollipops! Commercial groundskeepers seem to be the worst offenders of this practice, as you can see in the photo below. Texas Rangers have a beautiful loose shape and should be allowed to keep it. If you feel you absolutely have to cut back a plant, do it in March–one time during the year, only once! Or maybe plant a dwarf “compacta” variety instead. END OF RANT.
These 4 Texas Rangers in a parking lot have been severely trimmed. Whoever developed the horticulture plan for this commercial area should have chosen the Leucophyllum frutescen ‘compacta’, the low growing variety of the plant.
Amazon Burning- what you can do
The new President of Brazil ran on a platform of developing the Amazon. What we are all seeing now is that landowners, particularly cattle ranchers, took that to give them a greenlight to start burning their way deeper into the life-giving jungle after he took office.
Now we can all be outraged as Presidents Macron and Trudeau have been on Twitter or we can actually do something about it in the real world. Countries like Pakistan, India, China, Senegal, Nigeria and even tiny Nepal have already embarked on programs to plant millions of trees.
While we can have no hope of getting support from the current administration in Washington D.C. for a massive tree planting effort in the U.S. I am confident that local groups, like the Tree People in Los Angeles or the National Forest Foundation, will continue and expand their Plant-A-Tree programs in cities, towns and forests across the country.
If no organization near you is doing it at the very least plan to add a tree to your garden this fall when planting season begins. If every person in the U.S. planted just one tree we would have 329 million new trees which would help offset the damage being done right now in the Amazon.
On my continuing travels through Louisiana, I have noticed that few homes have anything that resembles a garden with shrubs and flowering plants artfully arranged. The more common gardening feature is the lawn, a large mowed green area around the home. Upon taking a closer look, I realized that many “lawns” are simply native grasses and other low growing plants sheared to slightly above ground level. It is an act of self-defense. Extremely fast-growing native shrubs and trees take over every space that is not regularly cut back in this hot, damp climate.
A garden has been planted around the Oplousas Louisiana courthouse including purple and pink Crepe myrtles.
The exception to this emphasis on lawns, are the Crepe myrtle trees (Lagerstroemia indica) planted by homeowners. They are ubiquitous.
These natives of southern China were introduced into Charleston, South Carolina by plant explorer and botanist to King Louis XVI, André Michaux, in the mid 1700s. The name is sometimes spelled Crape myrtle, but Crepe myrtle now seems preferred. Whatever the spelling, they took the South like wildfire. People loved them.
This hot pink color seems to be the most popular Crepe myrtle. It is a bright contrast to the green of the South and the brown of the southwest.
And Crepe myrtles loved the heat, lots of sunlight and the slightly acidic soil.
Some newer hybrids have been developed to tolerate chillier winter conditions, including frost. And–surprisingly–they are somewhat drought tolerant.
Correcting alkaline soil conditions
It’s that “acidic soil” part that is an issue in a hot, dry climate. Most of the soils in the desert Southwest are alkaline, but alkaline soils can be corrected to a soil condition that Crepe myrtles love in two ways:
Add 4 to 6 inches of organic mulch and dig it in to a depth of one foot. Within a year or two the soil will become more neutral. Mulch should be added every year.
Add sulphur to the soil and dig it in which will also balance the pH. While this maybe a faster way to rebalance soil, be very careful with this because too much sulphur can be harmful.
And be sure to deep water your Crepe myrtle tree at least once a month in summer. Drought tolerant doesn’t mean “no-water-required.”
Here are some Crepe myrtles I’ve admired in Louisiana:
Two colors of Crepe myrtles planted together. The neighbor, behind, planted a white one which is now at least 25 feet tall.These Crepe myrtles have been carefully pruned to allow an open area beneath them on the University of Louisiana campus. Their broad growth is a characteristic of the hybrid. Some hybrids grow tall and narrow, some broad, and there are dwarf hybrids that are perfect for hedges.White Crepe myrtle trees are less common than the various shades of pink and purple. This one was ladened with white flowers. This home actually has a small garden planted around it!
Mesquites seem to have become the Street Tree of choice in some cities in the arid Southwest. Cities can line the streets with allées of Honey mesquite (Prosopis glandulosa) or Velvet Mesquite (Prosopis velutina) knowing full well that maintenance is not going to break the city budget. As natives these trees thrive in harsh, dry climates with almost zero upkeep. And Fall is the best time to plant them.
The Mesquite is for all practical purposes a plant-it-and-forget-it tree, but the shade it provides allows other plants thrive.
When you plant keep in mind that irrigating and fertilizing a mesquite is a mistake and planting one in a lawn that is regularly watered can be a disaster: the roots will be shallow, the tree will become top-heavy and topple over in the Spring and Fall windstorms.
A third native mesquite, the Screwbean (Prosopis pubescens) is more of a tall, thorny shrub and is best planted in an out of the way place. One Screwbean mesquite I saw not long ago was tucked back in a no-irrigation zone of alarge Las Vegas garden where it and a nearby Desert Willow (Chilopsis linearis) were surrounded by a protective circle of agaves. A good choice of companion plants!
A Desert Willow and a Screwbean Mesquite make good companions to these agaves.
In addition to these three, other mesquites from Chile and Argentina have been introduced into the Southwest and have cross-bred like crazy with the locals. And thorns have turned up unexpectedly on supposedly thornless mesquites.
The problem with these fast growing, very drought tolerant trees is that they don’t give us colorful blooms in our gardens. Yes, yes — I know they “bloom”–after all, that’s where Trader Joe’s Mesquite Honey comes from–but the blooms are very subtle. Bees may notice them, but the average person driving along the street won’t.
So here are a few recommendations of trees to plant this fall that will produce colorful blooms in summer.
The first two I have already written about but are worth mentioning again.
This Chitalpa tree was planted as a “whip” about 4 years prior to this photograph being taken.
The Chitalpa tree (Chitalpa x tashkentensis) was especially developed for low water usage gardens — by Russian scientists, no less. The “tashkent” in its name is the capitol city of Uzbekistan formerly part of the old Soviet Union where the scientists worked. Why those scientists spent time developing a ornamental garden tree–rather than a practical fruit or nut tree–I will never figure out. But I thank them.
Anyway…it is definitely a favorite because it blooms in pink, or white, or lavender for months on end in summer. It needs some watering, grows 2 or 3 feet a year and reaches a height of 25 feet tall. Bonus: hummingbirds love it.
In addition to pink and hot pink, one Crepe Myrtle has showy white flowers in summer.
The Crepe Myrtle (Lagerstroemia indica) can be a glorious blast of color in the summer, although be aware that it does need watering to do its best. A row of them behind our local library did not get irrigated this summer and failed to put on the usual bright show of flowers.
By nature the Crepe Myrtle is a shrub although some plant growers train them to be a small tree or standard. It tolerates neutral to slightly alkaline soil so be sure to add mulch around it at least once a year.
The Gold Medallion tree (Cassia leptophylla) is a Brazilian native that is now being planted in drought tolerant landscapes in the Southwest after being introduced to the U.S. by the Los Angeles Arboretum in 1958.
This young Gold Medallion tree will easily grow to twice this height.
It flowers with huge basketball size clusters of yellow flowers at the ends of branches and the hotter the weather the more the blooms.
Happily, it also tolerates mildly cold weather down to 25° F for a short time. The City of San Francisco, of all places, is using it as a street tree and it is chilly there, for sure! The Gold Medallion tree needs soil that drains well and do not over-irrigate. It’s seeds are poisonous.
Now about Oleander…Yes, it blooms in summer, is drought tolerant, and grows fast. And every bit of the plant is poisonous–leaves, branches, flowers–everything. Seriously, it can kill people.
CLIMATE CHANGE In the last few days many of us in the Southwest were blessed with rain. It soaked into the earth in some places and in other areas created flash floods. This rainfall came from the remains of Hurricane Sergio. As the Pacific ocean warms up along the California coast, we can expect more after-effects from hurricanes and, before long, full-fledged hurricanes actually blowing into Southern California and eastward. This year the water temperature off So. Cal. was 78° F. That’s 10° above the historic normal. The weather folks tell us hurricanes need 80° F water temperature for energy–and that’s only 2 degrees away. I look at the photos of the destruction caused by Hurricane Michael in Florida and hope we do not have to experience that here.
Mother Nature plants in the Fall and so should you. Instead, however, of simply deciding which trees, shrubs or perennials to add to your arid garden this Fall, you may be looking at which plants you need to replace. The record-breaking heat in the Southwest and California (and Australia!) this last summer baked the leaves on many plants and turned them brown overnight. On others the leaves simply fell off the branches. The plants appeared dead.
After looking as if nearly dead, the cooler weather has brought new growth to this white azalea which thrived for years in a micro-climate backed up against a wall in almost total shade.
But don’t yank these sunburned plants out of your garden yet, especially now that the rains have come. Wait two or three weeks. The roots of dead-looking plants may have survived the heat and be ready to regrow.
If, however, you decide to replace some plants, consider the suitability of the ones you choose for replacements. The heat this last summer will probably be back next year and for many summers to come. You may want to select more desert-like plants or take steps now to create micro-climates for parts of your garden that suffered most from the heat by adding shade-producing and heat-reducing plants. And, unlike the Beanstalk of Jack-and-the-Beanstalk fame, the plants to create micro-climates don’t grow sky high overnight. Planting them this Fall–rather than waiting until Spring–will give them a head start on growth over the winter.
Plant now to create micro-climates in your garden
For starters you can help cool off your entire garden by planting a fast-growing hedge in front of a hot wall. This can be effective with both cement block walls around your property and the stucco walls of your home. The shrubs’ leaves will block the sun from heating up the wall during the day so there will not be as much drying heat to be released after dark. Overall your garden will feel cooler and a bit less dry. And a cooler, slightly damper garden is better for all plants — and people.
Two drastically different hedge plants that grow fast are Pampas Grass (Cortaderia selloana) and Japanese privet (Ligustrum japonicum).
Behind this Pampas grass is a dull gray block wall. In one year it was covered up.
Pampas grass is close to being a Jack-and-the-Beanstalk plant. It will shoot up to as tall as 20 feet in one year, and should be cut back to 18 inches high in mid-winter. But be aware: its blades have rough edges that can cut skin so wear gloves when cutting it back. And it may be very difficult to remove if you change your mind later. It is definitely a statement plant.
In Springtime the Japanese Privet hedge bursts into bloom.
The Japanese privet is more ordinary looking–just a basic green hedge. It grows about two feet a year, however, and is quite drought tolerant. Poor soil conditions do not seem to bother it either. In Spring it is covered with white flowers that look almost like lilac blooms, but don’t smell nearly as nice as lilacs. You can see these and other shrubs for hedges in arid gardens here.
Planting a tree for more shade is another way to create a micro-climate to help other plants in your garden survive in hot weather.
One rapid growing tree that is suitable for arid gardens is the Chitalpa (Chitalpa tashkentensis) which will grow about 3 feet a year to a maximum height of 25 feet. It is a hybrid of the Desert Willow and the Catalpa tree that was created specifically to thrive in hot, dry climates. While it likes balanced soil, slightly alkaline conditions will not impair its growth. I especially like it because it has long-lasting, pretty pink-white blossoms, an open branch structure and provides dappled shade, rather than dark shade. You can see othertrees for hot, dry gardens here.
The right way to plant a tree or shrub
The hole for planting should be 2 1/2 times as wide as the root ball, but do not make it deeper than the root ball. The crown (the part where the roots meet the trunk or main stem) should be at or slightly above ground level–not submerged in the hole. Be sure to add a lot of rich organic mulch into and around the hole you dig for a new tree or shrub to provide nutrients for growth, especially root growth during winter. Really soak the soil with water around the planting hole and, once planted, water the tree regularly until the plant is established.
Now here is one last recommendation for coping with our hotter, drier summers and the damage of relentless heat. In my last post I wrote about applying organic mulch around plants, trees, and in flower beds to help supply nutrition. Another benefit of mulching is that mulch provides an insulating layer to protect the roots from scorching summer heat and winter cold. That’s right — winter cold and its potentially damaging effect on plants is right ahead of us now. More about this in an upcoming post.
For months now in 2018 the daily high air temperature has been above 90 degrees (F) (32C) which means that plants in hot dry gardens in the Northern Hemisphere have gone into summer dormancy. Even drought-tolerant plants and natives just hunker down and try to survive until Fall when the air and earth cool down. (One of the few summer bloomers is the Crape Myrtle tree, shown above.)
As your garden’s best friend and caretaker, you should water the plants regularly, but do not fertilize the plants in your arid garden in an attempt to make them bloom or grow. They are thirsty at this time of year but not hungry now so deep irrigation is best. They do not want to grow. They do not want to produce seeds. And only a few bloom during summer dormancy phase.
Blooming color in summer
Crape Myrtle blooms in hot pink and white, both shown here. They also have paler shades of pink and even one with lavender blossoms. Best of all they love the heat!
My absolute favorite of the summer bloomers is the hot pink Crape myrtle (Lagerstroemia indica), a native of India and China that thrives all across the southern U.S. in both dry and damp climates. By nature the Crape Myrtle prefers acidic soil, not the alkaline soils of the American West. In the South where the soil is acidic and it rains in summer, the Crape myrtle grows to 20+ feet tall. In the very dry hot Southwest, the trees bloom beautifully but rarely reach that height.
If you are planning to plant a Crape Myrtle tree this fall after the weather and earth cool off, be sure to add a lot of organic materials to the soil around it and water the root ball thoroughly–soak it through–before it goes into the ground to encourage good root growth. It’s a good idea to mulch around the tree every year so it remains happy and blooming every midsummer.
Climate Change Update
During this last month in the summer of 2018, people in Spain, Japan, and countries around the world experienced record-breaking temperatures of 117 degrees (F) (47 Celsius) and higher. Off the coast of La Jolla, California, the usually cool Pacific Ocean temperature was 78 degrees which is 10 degrees above normal. At the southern end of Florida, the water temperature reached 98F (36 C) Some fish, of course, can swim away from uncomfortable temperatures, but underwater plants and slow moving and non-moving animals are stuck and may die out.
For centuries palm trees have been symbols of comfort and safety whether
Spied in an oasis from afar in a scorching hot desert or
Standing tall as a “land-ho” sign after crossing a vast stretch of ocean or
Simply marking the beginning of warm weather country when traveling south in the U.S.
As symbols or signs, palm trees are great. I love seeing them lined up along The Strip in Las Vegas, and Arroyo Parkway in Pasadena and Canon Drive in Beverly Hills. But as for planting a palm tree in a residential garden…I am less enthusiastic.
Three Mexican fan palms.
Plant a Mexican fan palm (Washingtonia robusta) or a fruitful date palm (Phoenix dactylifera) and within a few years you have a tall, round brown column in your front yard. The graceful green fronds will have grown out of sight and cast very little shade.
The Mexican Fan palm has vicious thorns on its fronds and a prick from one thorn can cause an infection. And if your sky-high date palm produces fruit, the dates will drop and make a mess—albeit a tasty mess—in your yard.
But there are two and a half smaller palm trees that are more suitable for home gardens in hot, dry climates.
The Pindo palm (Butia capitate) has long fronds, like the date palm, but grows very slowly to 20 feet tall and about the same width. It produces a yellow fruit that in some countries is turned into jelly or wine. It is the smaller palm in front in the photo. Behind it is a Mexican fan palm which is growing its way to 60 feet tall. Both planted at the same time.
The Mediterranean Fan palm, (Chamaerops humilis) as the name states, has fan-like fronds similar to the Mexican fan palm, but it is essentially a palm shrub, not a palm tree. Many people trim the lower fronds off the multiple trunks to give this plant a more traditional “palm tree” shape. A slow grower may reach 15 to 20 feet someday. Its small, brown fruit is not edible.
Both these smaller palm trees can survive chilly weather, even a quick light dusting of snow!
And now for the “half palm tree”. It is commonly called a sago palm, but it is not a palm at all. This low growing cycad is closely related to evergreen pine trees. It can be an attractive addition to a palm garden oasis and grows really s-l-o-o-o-w-l-y. Be sure to plant in a backyard; thieves steal them from front yards regularly because they are very expensive plants. Another note about the sago palm: its bright red fruit can be toxic to dogs and other small animals and is not good for humans of any size.
So even though palms like being planted in warm soil and can be planted in warm weather if watered sufficiently, consider how it will look in a few years. In my opinion, it is better to invest your money and time planting a fast growing Chitalpa tree (Chitalpa x tashkentensis).
Shortly after moving to Las Vegas back in the 1990s I went on a hike with the Sierra Club in what is now the Red Rock Canyon National Conservation Area. Our destination on this hike was an old abandoned ranch about 3+ miles from the pull-out on Highway 159 where we parked our cars. The ranch owners had walked away from the ranch years ago and turned it over to the Bureau of Land Management. (And the BLM had pretty much just ignored the place.)
So about 10 of us tromped off across the wide canyon floor. As a newcomer to desert hiking I forgot to bring water and it turned out there was no water at this old ranch. Just a weather-beaten house, a couple of fences that tilted and sagged…AND a row of pomegranate bushes still producing big red pomegranate fruit. These 8-10 foot high shrubs had survived for years with only the water that fell from the sky. And in Las Vegas, the average annual rainfall is about 4 inches! It might be a bit higher up in Red Rock Canyon, but not by much.
This was evidence that pomegranates grow well even under very dry conditions. And if you add a little bit of care and water they will do even better. Another plus: the leaves turn a lovely yellow in Fall and at Christmas time the fruit–if you haven’t picked it–looks like red ornaments in your garden.
So if you want a low-water usage fruit to harvest from your own backyard, plant a pomegranate. The ‘Wonderful” variety is an excellent choice and will do well even with neglect.
But don’t neglect taking water with you on a desert hike. I have always had water with me ever since that day.
This view is from the pull-out where we parked our cars. The abandoned ranch where the pomegranates were growing is up against those mountains.
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