Lessons From a Heat-Stressed Desert Garden

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Desert Garden heat with little fuss.

Let’s face it. Hot summers are not surprising to desert dwellers. In fact, a typical desert garden with native and desert-adapted plants will weather intense heat with little fuss.

However, this summer has been one for the books and I’ve seen signs of heat-stress that I’ve never seen before. And yes, within my own garden.

Desert Garden heat-stressed Rock Penstemon and Golden Barrel Cactus

Heat-stressed Rock Penstemon and Golden Barrel Cactus

I must admit that it’s been hard to see certain plants struggling in my desert garden and I know you may have similar feelings. So, why has this summer been so much more difficult than others?

Pink Trumpet Vine partially defoliated due to the heat in desert garden

Pink Trumpet Vine partially defoliated due to the heat

While it is normal to have several days above 110 degrees F., the summer of 2020 is one for the record books. We have experienced not just a couple of stretches of above-normal temps but, several long spans of infernal heat. Damage to plants is often cumulative. This means that the more days of above-average (or below-average) temperatures – the higher incidence of reaction from plants.

Take a walk outside in your garden. You will likely notice some plants that are yellowing, wilting, or have given up and died. However, you may also note that there are some that are doing well.

Why is that? Let me show you some examples from my own garden – the good AND the ugly.

Let’s start with the ugly:

New Mexican Fence Post cactus transplants desert garden

New Mexican Fence Post cactus transplants

In March, much of my backyard was renovated. This included the addition of two separate plantings of Mexican Fence Post cacti. They are located along my back wall and as you can see, one is doing very well while the other makes me cringe when I see the yellowing.

Does the yellowing cactus need more or less water? No. Many succulents yellow in response to summer heat. Of course, this very hot summer has made it more severe. So, why the difference between the two?

The one on the left gets filtered shade in the afternoon from a nearby Palo Verde tree. You can tell that the one on the right doesn’t get any shade but full afternoon sun. In a normal summer, it would be normal to see some yellowing that will return to green once temperatures cool. I am hopeful that will happen. As plants age, they tend to handle heat stress better and as these are young, the stress was especially severe.

Signs of heat stress desert garden

Signs of heat stress

In another area of my garden, I have Green Desert Spoon and Hardy Spineless Prickly Pear, which are very heat-adapted. Yet, they do show signs of mild heat-stress that I haven’t seen before. But, they will green back up in fall. Other plants that are struggling include Artichoke Agave, Gopher Plant, and Shrubby Germander.

I am thrilled that my young Desert Willow tree in this photo is thriving despite the heat. I have four others scattered throughout my landscape and all are doing just as well.

Here are some of the good:

Young Baja Ruellia (Ruellia peninsularis) doing very well in desert garden

Young Baja Ruellia (Ruellia peninsularis) doing very well. The neighbor’s Dwarf Myrtle isn’t.

'Sparky' Tecoma shrub (Tecoma 'Sparky') in desert garden

‘Sparky’ Tecoma shrub (Tecoma ‘Sparky’)

Pink Muhly (Muhlenbergia capillaris). Will soon burst forth in burgundy plumes in fall

Pink Muhly (Muhlenbergia capillaris). Will soon burst forth in burgundy plumes in fall.

Gold Lantana in full sun all day in desert garden

Gold Lantana in full sun all day

Feathery Cassia, Purple Trailing Lantana, and Yellow Bell shrubs are also doing well.

Here are a couple of exceptional performers that get full, reflected sun:

'Rio Bravo' Texas Sage in desert garden

‘Rio Bravo’ Texas Sage

Bougainvillea in desert garden

Bougainvillea

There are still six weeks of summer heat ahead of us. So, what should we do for now?

  1. Be sure plants are receiving enough water. You may need to increase the frequency when temps are above 110 degrees.
  2. Don’t fertilize. Feeding plants simply makes them work harder to produce new growth when all they are trying to do is deal with the heat.
  3. Don’t prune away heat-damaged growth until September. While brown leaves are ugly, they are protecting the interior of the plant. Some pruning is recommended in mid-September, which I teach in my Shrub Pruning Workshop.
garden in the desert with small tree and plants

We don’t know if this summer will be an anomaly or the beginning of a new normal. But, instead of throwing in the towel, I invite you to do the following instead:

Take a stroll through your garden and take note of which plants are doing well and those that aren’t. If this is to be the new norm, it would be a good idea to add more of those that handle the heat well.

desert garden

I am not going to make any major changes in my own garden. Most of my plants have done just fine in past summers. I’ll replace the few plants that died but am hopeful that next summer will be one with average temperatures. If not, then I know what plants have withstood the heat best.

Before we know it, fall will be here, and I for one, can’t wait!

Gorgeous Germander for Desert Gardens

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Mesquite Trees and Crazy Branches

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mesquite tree Branches

Have you ever paused in the shade of a mesquite tree (Prosopis spp.) and noticed that its branches grow every which way? 

I was reminded of this when I was visiting a client earlier this week and was advising him on how to care for his mesquite tree. I looked up and saw a cluster of branches growing up, down, sideways, and in curvy pathways.

mesquite tree Branches

Texas Honey Mesquite (Prosopis glandulosa)

In an ideal situation, mesquite trees resemble the shape of more traditional tree species, as shown above. However, they don’t always turn out this way. 

mesquite tree Branches

Have you ever wondered why mesquite trees grow in such crazy ways?

The answer is quite simple – in nature, mesquites grow as large shrubs. The branches of shrubs grow in all directions, up, down, sideways, etc., and so do mesquites.  

The problem arises when we train them up as trees, and their branches don’t always behave as trees do. Because of this, mesquites that have been pruned into trees, do best being pruned by a professional, particularly when they are young and certain branches are being chosen to remain while others are pruned off.

mesquite tree Branches

Of course, this doesn’t always happen, and you can see the results of bad pruning practices in many places. 

I do love the shade that mesquite trees provide and I must admit that I enjoy a good chuckle when I see the unusual shapes that some mesquite trees have taken.

How about you? Have you ever seen a mesquite tree with crazy branches?

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Sometimes The Best Thing To Do About Aphids Is Nothing

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To Do About Aphids

What do you do when you spot aphids on your plants?

Do you reach for the nearest bottle of insecticide? Spray them off with a hose or remove them with your fingers?  

Believe it or not, sometimes the best thing is to do nothing.

So, is this something I learned in school? No. I figured it out by observing the plants in my first garden.

To Do About Aphids

I remembered this early lesson when I passed by a severely pruned oleander shrub in front of my favorite bagel shop.  

To Do About Aphids

The oleanders were growing back nicely. However, there were yellow aphids on the young leaves.

Years ago, my oleander shrubs had an infestation of yellow aphids like this, and I was anxious to get rid of them. Really, this is our first reaction when we see bugs on our plants – we want them gone.

I had several methods at my disposal – insecticidal soap, a strong jet of water or my fingers – all of which, would help get rid of most of the aphids. But, life got in the way, and I didn’t have a chance to get out to treat my shrubs until about ten days later.  

Can you guess what I found?  Not a single aphid.  I didn’t have to do a thing, and the aphids were gone, and my shrubs look great.

So, what happened to the aphids?

When harmful insect pests first appear, it can take a week or two before their natural predators follow. In the case of aphids, lacewing and ladybugs showed up and ate the aphids.  

To Do About Aphids

Plants are tougher than we give them credit for and can handle a certain amount of insect pests without any adverse effects.  

So, when I come back in a couple of weeks to the same bagel shop, I expect to see no aphids in sight and a healthy oleander shrub.

The lesson here is that you don’t need to freak out when you see aphids as the normal cycle of nature will take care of them. However, you can step in to get rid of them if you see adverse effects on plants such as wilting, smaller blooms, or discoloration.

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Hop Bush: The Alternative to Oleanders

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No matter where you live, you will see the same shrubs being used over and over again in countless landscapes. While the shrubs may be attractive, their overuse throughout neighborhoods creates a boring appearance because they are so common.

oleanders

In California, Nevada, and Arizona, oleanders have held a prominent spot in the landscape for years. Their popularity is due to their lush evergreen foliage, ability to withstand intense heat, and their pretty flowers.

However, their overuse in many areas makes their beauty less impactful and frankly, almost forgettable.

 At a recent conference, this point was put quite succinctly by the head of horticulture for Disneyland who said,

“When things are expected (in the landscape), they become less powerful and impactful”.

His statement sums up what happens when we use the same plants over and over.

In the case of oleanders, there is another problem.

Oleanders

Oleanders are susceptible to a fatal disease called, oleander leaf scorch. This disease has come from California into Arizona where it is popping up in neighborhoods in Phoenix and also Lake Havasu. I have consulted with several cases affecting large, mature oleanders in Arcadia, Biltmore, and Moon Valley areas in Phoenix. 

This bacterial disease is spread by leaf-hopper insects and there is currently no known cure or control available. Infected oleanders slowly decline over 2-3 years before dying. To date, dwarf oleanders have not shown signs of the disease, only the larger forms. But, that could change sometime in the future.

Objectively, there’s a lot to like about oleanders; they thrive in hot, dry climates with minimal fuss, have attractive dark green foliage, and add color to the landscape when in flower. However, their overuse in the landscape makes them less impactful and coupled with their susceptibility to oleander leaf scorch, people want an alternative. 

You can learn more about this disease that affects oleanders here.

Hop Bush: 

Hop Bush

When asked for another option for the large, tall forms of oleanders, I recommend Hop Bush (Dodonaea viscosa), also known as Hopseed Bush.

This native desert shrub has attractive, evergreen foliage and a similar growth habit to oleander. They grow up to 12 feet tall or prune to a shorter height.

Hop Bush

Use Hop Bush in the same ways as oleanders to provide a nice green hedge or privacy screen.

Hop bush flower

Hop bush flower

While they don’t have colorful flowers; they have lovely foliage that is only mildly poisonous as opposed to oleanders which are highly toxic.

Hop bush

Hop bush has a lovely natural shape or prune as a formal hedge.

Want to learn more about this oleander alternative? In my latest Houzz article, I share what types of plants look nice next to hop bush, how to care for them and show a purple-leaf form.

I hope that you find a spot for this lovely shrub in your landscape.

Have you ever seen hop bush growing in the landscape?  

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Old, Overgrown Plants: Time to Start Over?

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newly-planted landscape

Have you ever driven by a newly-planted landscape?  If so, you probably noticed that many of the plants were quite small.  

I like to joke that sometimes you need a magnifying glass just to see the new plants. But as small as they are, within a short amount of time, those plants start to grow.  

overgrown plants are unattractive.

Look at the same landscape three years later. The plants are well-established and look great.  

Fast forward eight-ten years, and you may start to see signs of some plants becoming overgrown and unattractive.

When this happens to shrubs, we can often push a ‘restart button’ (for most types of shrubs) and prune them back severely in spring using a good pair of loppers, which reduces their size. I use my Corona loppers to do major pruning of my shrubs.

However, there are some plants where this approach doesn’t work.

Let’s identify a few of these plants and how to deal with them once they outgrow their allotted space or become filled with old, woody growth.

Desert Spoon (Dasylirion wheeleri)

Desert Spoon (Dasylirion wheeleri)

Desert spoon is one of my favorite plants.  I love how its blue-gray, spiky leaves add texture to the garden and contrast with plants that have darker green foliage.  

Old, Overgrown Plants

After ten years or more in the landscape, desert spoon can start to take on a ragged, rather unattractive appearance, as well as grow quite large.

When this happens, I recommend that they be removed and a new one planted in its place.  

Now, some of you may think that may seem wasteful, but I invite you to take another look at your landscape and the plants within it.

Your outdoor space isn’t static and unchanging. Its appearance changes with the seasons with plants blooming at different times. Trees gradually extend the amount of shade they provide and plants change in size.  

A newly planted garden doesn’t look the same through the years, it changes.  

Trailing Rosemary (Rosmarinus officinalis 'Prostratus')

Trailing Rosemary (Rosmarinus officinalis ‘Prostratus’)

Rosemary is a good choice for those who want rich, dark green color in the garden. Bees love the light blue flowers that appear in late winter and spring, and the aromatic foliage can be used to flavor your favorite dishes.  

Old, Overgrown Plants

But, as time passes, it does get bigger, outgrowing its original space.  

Old, Overgrown Plants

When this happens, people start to shear their rosemary, which is stressful for the plant and contributes to sections of branches dying.

For those who don’t like the formal look, pruning rosemary back severely would be your first impulse. But, the problem with rosemary is that they don’t respond well to severe pruning.

So again, in this case, it’s best to pull out the old rosemary and add a new one, which will provide beauty for several years.

Rosemary hedge

Rosemary hedge

To avoid having to remove and replace rosemary too often, allow them plenty of room to grow to their mature size.

Red Yucca (Hesperaloe parviflora)

Red Yucca (Hesperaloe parviflora)

Red yucca is prized for its succulent, green leaves that resemble an ornamental grass and its coral flowers, which appear spring through fall.

red yucca Overgrown Plant

Once it has been growing seven years or more, red yucca may overwhelm the landscape visually. This is particularly true if the area it’s growing in isn’t very big.

Occasionally, some people will try to remove the outer leaves at the base. However, this is laborious and only serves to stimulate red yucca to grow back faster.

In those situations, I tell people that their plant has had a nice life, but it’s time to start over.

Newly-planted red yucca

Newly-planted red yucca

You may be thinking, why use plants that you’ll only have to replace after seven to ten years?

Well, all three of these plants add beauty to the landscape and are low-maintenance.

Another way to think of it is to compare your landscape with the interior of your home.  Do you make small changes to the decor of your home every few years to keep it looking fresh and attractive? The same should be true of the outside.

Replacing a few plants after seven years or more isn’t expensive. Don’t you think that the beauty these plants offer to your outdoor space makes them worth it?

What have you replaced in your garden recently?

Got Old, Overgrown Plants? Know When to Prune or Replace

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Made in the Shade: Yellow Dot

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It may surprise you to find that it is easier to find plants that thrive in the sun than in the shade.

Especially if you live in the desert Southwest. Why is this, you may ask?

Well, it can be hard to find plants that can handle the intense, dry heat of our climate while flourishing in the shade. While there are a number of lovely plants that can work in shady conditions, it’s hard to know which ones will, which is why I make sure to include my favorites for students in my online gardening class.

So, what do you do if you have a shady spot to fill?

Yellow Dot (Wedolia trilobata)

One of my favorites is Yellow Dot (Wedolia trilobata), which is a vining ground cover with lush, dark green leaves interspersed with yellow daisy-like flowers.

Here is a plant that does fabulously in dark shade and will handle brief periods of full sun. 

Yellow Dot grows quickly to 1 ft. high and 4 – 6 ft. wide and is hardy to 30 degrees. It’s susceptible to frost damage, which can be easily pruned back in spring.

One of my favorite characteristics of this lush green ground cover is that it has a long bloom period – spring through fall. 

It grows beautifully underneath trees, along pathways, and among boulders. You just want to be sure to allow enough room for them to spread.

So, if you have a difficult shady spot that needs a plant – try Yellow Dot.

How about you?  Do you have a favorite plant that does well in shady spots?  I’d love to hear about it!

Gardening in the Desert Southwest – Interview

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Too Much Salt Isn’t Good For You OR Your Plants…

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I have a weakness (well, one of many) to confess to you today….

I absolutely love salt.  

In fact, I have a theory that the reason that so many people love french fries is not the potatoes or the fat it is fried in. No, it is the salt that you put on them afterwards. I mean, can you imagine eating an unsalted french fry? 

In preparation for this blog post, I went through my kitchen and pulled out all of my salt & pepper shakers.

different types of pottery

It’s kind of embarrassing isn’t it?  I have so many.

But in my defense, I must admit that I collect different types of pottery and need salt and pepper shakers for each set.

My husband made me my wooden salt cellar, which I keep near the stove when I cook.

Now, I do not use as much salt as I used to. In fact, I am trying to be better about it.  When I visited the doctor earlier this week for my physical, I still had low blood pressure, much to my relief.

Well, we all know that too much salt is bad for you and can lead to health problems such as high blood pressure. But did you know that too much salt is not good for your plants as well?

Plants don’t get ‘high blood  pressure’ with too much salt, but they do have another problem that shows up.

salt burn

They get brown tips on their leaves, which we call ‘salt burn’.

white-crusty-salt-build-up-plants

Here is another way that you can tell plants are getting too much salt. Shallow watering causes the water in the soil to evaporate quickly, leaving behind the salts. The salts look like a white crust on the soil around your plants.

At this point you may be wondering how plants get too much salt?  

Well, both soil and water have naturally occurring salts in them. This is especially true in the Desert Southwest where our water is somewhat salty and our soils can suffer from salt build-up due to high evaporation.

So what do you do if you have indoor or outdoor plants that have brown tips?

The solution is very easy.

Water deeply.

That’s it!

salt build-up

Here is a shrub that has signs of salt build-up. I encountered with one of my clients during a landscape consultation – he had other shrubs that looked similar.

I will tell you what I told him:

If your outdoor plants look like this, first water the affected plant with your hose on a slow trickle for at least 2 – 3 hours.  This helps to ‘leach’ or flush the salts away from the roots.

Thereafter, adjust your irrigation schedule so that your shrubs are watered to an approximate depth of 18 inches deep each time. Sadly, most people water too often, too shallow and not long enough.  

For example, I water my shrubs and perennials every 5 – 7 days in the summer. This takes approximately 2 hours for my plants to be watered to a depth of 2 ft. Of course the time it takes to water that deeply is different for each landscape and is dependent on a variety of factors including soil type and water pressure.

If your houseplant has brown tips (salt burn), then simply flush the salts out by deeply watering.  You can do this by putting your plant in the sink or bathtub and let water slowly trickle on your plant for 1 – 2 hours.

I cover landscape irrigation in depth with my students in my online course, Desert Gardening 101, but for those of you looking for advice right now here’s what I recommend. Search online for watering guidelines on your city’s website – most have schedules including recommended depths.

So in closing I’ll leave you with these two tips:

Be sure to limit your salt intake AND water your plants deeply to prevent salt burn.

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Have You Suffered From Color Blindness in the Garden?

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Last month, I diagnosed my first ever case of color blindness.

Now, I realize that I am no doctor or medical authority. However, as a horticulturist, I am somewhat of an expert in the garden, which is where I made my diagnosis.

Color Blindness in the Garden

Attractive drought-tolerant landscape in the Southwest

Before I tell you more about my unorthodox diagnosis, I invite you to look at this photo. It’s of a lovely low-desert landscape filled with a mixture of trees, shrubs, and cacti.

Color Blindness in the Garden

Front entry to desert garden with flowering Parry’s Penstemon

Here is another lovely desert landscape with succulents, vines, and a flowering Parry’s Penstemon.

My client has a garden much like those photographed above. It’s filled with a variety of flowering shrubs, agaves, cacti, and ground covers.

So when he called me in a panic telling me that the plants in his garden were doing poorly, I came ready to help him out.

However, once I got there, I didn’t see any problems. His plants looked great! He told me that his plants did look fine before he left on vacation. But, when he returned, they seemed less green and somewhat sickly.

It took me a while to assure him that his garden was healthy, and then we made small talk and I asked him where he went on vacation. His answer? Michigan!

That was an AH-HA moment! I now knew what the problem was, and it wasn’t with his plants. It was his eyes and his perception of green.

Let me illustrate:

Color Blindness in the Garden

A large lilac bush next to a winery in Traverse City, Michigan

Michigan is one of my favorite states to visit because my oldest daughter lives there with her family.

It is a beautiful place to explore with lovely gardens.

Color Blindness in the Garden

Colorful bearded iris in the Frederik Meijer Gardens in Grand Rapids, Michigan.

There are stunning botanical gardens awash with vibrant flowers spring through summer along with vivid greens.

Color Blindness in the Garden

Example of a Michigan Farm at Frederik Meijer Gardens

Visiting Michigan in summer is something that I look forward to every year. The gardens with their lush greens are a soothing balm when I’m tired of the hot, dry summer heat back home.

My client had an experience much like this, enjoying the saturated greens of a Midwest summer before he returned home to his garden.

Now, take another look at the desert landscapes below:

Color Blindness in the Garden
Color Blindness in the Garden

Do they look a little less colorful to you? Dare I say drab? 

When we travel to regions outside of the desert, our eyes become accustomed to bright, saturated colors that are part of that landscape. Then, when we return home, the soft, subtle shades of green are less evident to us due to the ‘green overload’ we are returning from.

As I explained this to my client, he finally understood that there was nothing wrong with his plants, just his eyes.

The good news is that this is temporary color blindness and that his garden will soon look as beautiful and vibrant as it did before he went on vacation.

Have you ever suffered from temporary color blindness in the garden?

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5 Reasons You Are Struggling With Your Desert Garden

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The 5 Most Common Mistakes People Make in the Desert Garden

I am always looking for ways to help people on their desert garden journey and so I’m offering a FREE class on 5 reasons you are struggling with your desert garden.

As a horticulturist and landscape consultant, I have seen people making the same mistakes, which prevent them from having a beautiful outdoor space.

Because of this, they unintentionally ‘hurt’ the plants by over-maintaining them and spending money on unneeded products and landscape services.

If this sounds like you, I AM HERE TO HELP!

I’ve been helping people like you for over 20 years and I can help you too!

Free Webinar AZ Plant Lady

This LIVE class is on January 17th, at 1:00 MST. *If you want to register for this free class, but can’t attend it live, it will be recorded so you can watch it at our convenience for a limited time.

Knowledge is power and once you know what you are doing wrong in the landscape – you have taken one GIANT step in having a desert garden that you are proud of.

CLICK the following link to learn more and register – http://bit.ly/2RpFFb5

I hope to see you there!

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Design Notes From the Field: A New Build, Metal Art, Weeds, and Shade

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design notes landscape

I’m back with design notes from the field, where I share observations and recommendations from my work as a landscape consultant. This edition features a new build, metal art, weeds, and shade. I hope that you can pick out helpful tips that you can use in your landscape.

Up first, is a new house that is being constructed in east-central Phoenix. The home that used to stand on this lot was taken down to the foundation and an energy-efficient home is coming up in its place. I was hired by the architect to design a landscape that will fit its clean, modern lines.

Several years ago, I solely worked as a landscape designer, working with homebuilders, creating new landscapes from scratch with a blank palette. Nowadays, as a landscape consultant design is just one aspect of what I do as part of an overall plan within an existing landscape, which also includes maintenance recommendations. Now and then, I create one for new homes, and this one has some fun challenges.

The look the architect wants is simple and uncluttered with room for the new homeowner to add to it if desired. So, I am concentrating on using plants to create a framework. This includes two trees in the front along with two along the west-facing side to provide screening from the road and protection from afternoon sun.

Foundation plants will soften the base of the house while taller shrubs will soften the corners. Ground covers will add low-level interest along with a few agave and cactuses for an accent.

A splash of color will be added by the front entry with the placement of a large, colorful pot filled with an easy to care for succulent.

design notes landscape

Often, I am asked for advice on what to do in somewhat unique situations. In this case, the homeowner needed advice for what to do for the wall behind the BBQ, which keeps turning black after grilling. 

I tend to look at problems like this as opportunities for adding more interest to the outdoor space. In this case, I recommended adding garden art in the form of rusted metal botanical panels. There is a local artist in Phoenix who creates metal panels with plant shapes cut out of them. He offers standard pieces but also does custom work. 

The rusted metal garden art will add welcome interest behind the BBQ as well as disguise any blackened area on the wall.

design notes landscape

Here is an example of the metal botanical panels from another client’s home, which was where I first encountered the work of this artist. You can learn more about this metal artist here. 

design notes landscape

Weeds will always be a problem in the landscape, like these I saw at a client’s home growing through the patio. The solution to this area is to slowly pour boiling water on weeds growing through the cracks, which will kill them. For travertine, only do this if the stone is sealed. 

design notes landscape

To wrap our design notes, here is a landscape where the homeowner wanted to concentrate on plants up close to the house and not add any further out. Now if this front yard didn’t have any trees, the absence of plants would cause it to look barren and washed out. However, the patterns from the branches of the ‘Desert Museum’ palo verde add beautiful patterns on the ground, so you can get away with leaving it bare, which draws attention to the lovely shadows of the branches.

I hope you have enjoyed this latest session of design notes. I’ll have more for you in the future.

**Stay tuned for a special announcement that I’ll be making the beginning of September. I’m working on a new project that will enable me to help you even more to create, grow, and maintain a beautiful outdoor space in the desert. I’ve been working on it for a while and am so excited to share it with you soon!

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