Oleander Leaf Scorch Strikes Again…

Do you have oleanders?  If so, you might have heard of a fatal bacterial disease called oleander leaf scorch that affects oleander shrubs.

This disease is slowly spreading and I have been seeing it more often when I visit clients.  

I wrote an earlier post about oleander leaf scorch, its signs and how it affects oleander shrubs, which you can view here.

Earlier this month, I visited another client whose entire backyard was surrounded by tall oleander shrubs that were quite mature.  She suspected that her oleanders were starting to show signs of oleander leaf scorch and it turns out that she was right.

oleander leaf scorch

Her suspicions began when she noticed browning of her a few of her oleander shrubs that began this spring and was worsening as summer progressed.

It’s important to note that browning of oleanders doesn’t necessarily mean that they are infected with oleander leaf scorch – browning can be caused by any number of problems from drought stress, salty soil or other excess minerals in the soil.

characteristics of oleander leaf scorch disease

However, a closer look at the foliage showed some of the characteristics of oleander leaf scorch disease with the outer leaves and tips turning brown.

This occurs because the bacteria rapidly multiply, blocking the vascular system of the plant. 

sign of oleander leaf scorch

These browning tips are also a sign of oleander leaf scorch, but this particular sign can also indicate high salts in the soil.

Even if you see only a few leaves affected, the entire shrub is infected and will die within 3 – 5 years.  Because this disease is spread by a flying insect called a sharpshooter, not all oleander shrubs in a given area may be affected as it hops from bush to bush.  However, these insects carry the bacteria in their saliva and spread it to each oleander shrub that they feed from.

While I was able to tell my client that her oleander shrubs likely were infected this disease, the only way to confirm the diagnosis was to contact her local cooperative extension office and send in some leaves from her oleanders to be tested.

If the test comes back positive, she will need to remove all of her oleander shrubs.  While they will live 3 – 5 years after being infected, they will turn brown.  The most important reason for removal is to help keep the disease from spreading to other oleanders in the neighborhood.

For more photos and a detailed description of this oleander disease as well as a suggested replacement plant for oleanders, read my previous post, “Plant Disease: Oleander Leaf Scorch”

Badly Pruned Trees OR How Not to Prune Trees

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I have a love affair with trees.

It’s true. I love their beautiful branch architecture, foliage and the dappled shade that they provide. Living in the desert Southwest, shade is a valuable commodity with the relief it offers from the intense sun and cool temperatures it offers.

desert Southwest

For all these reasons and more, I can’t fathom why people would prune their trees like this, stripping them of all their beauty and much of their function.

Badly Pruned Trees OR How Not to Prune Trees

Badly pruned trees

The phrase that comes to mind when seeing something like this is badly pruned trees or how ‘not’ to prune trees.

Unfortunately, this is just one of many trees in this parking lot that have fallen prey to terrible pruning practices.

As a certified arborist, I see many bad examples of pruning, but I can honestly say that the trees in this parking lot are the worst.

Badly Pruned Trees OR How Not to Prune Trees

Years ago, my husband and I used to live next to the area in Scottsdale and the appalling pruning that was done to the trees was well known by me.

On this lovely day, the kids and I were on our way home from the Desert Botanical Garden when we drove past this shopping plaza. I quickly made a detour to see if anything had changed.

Sadly, they hadn’t. So, I took out my camera and started taking photos.

See if you can guess what each badly tree is:

Badly Pruned Trees OR How Not to Prune Trees

#1

Badly Pruned Trees OR How Not to Prune Trees

#2

Badly Pruned Trees OR How Not to Prune Trees

#3

Badly Pruned Trees OR How Not to Prune Trees

#4

Feel free to leave your answers in the comments section. After guessing, click here for the answers with examples of what the trees should look like when properly maintained.

Needless to say, you don’t need to know what type of trees they are to realize that they have been ‘butchered’.

Badly Pruned Trees and What They Should Look Like

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I recently shared some examples of ‘butchered’ trees and asked you to try to identify what each tree was. You can take the quiz here, if you like before seeing the answers, below.

As promised, here the photos of badly pruned trees and what they should look like:

Badly Pruned Trees

Badly Pruned Trees

Desert Fern (Lysiloma watsonii)

Photo: #1 – Desert Fern (Lysiloma watsonii)

Badly Pruned Trees and What They Should Look Like
Shoestring Acacia (Acacia stenophylla)

Photo: #2 Shoestring Acacia (Acacia stenophylla)

Badly Pruned Trees
Chilean Mesquite (Prosopis chilensis)

Photo: #3 Chilean Mesquite (Prosopis chilensis)

Badly Pruned Trees
Palo Brea (Parkinsonia praecox)

Photo: #4 Palo Brea (Parkinsonia praecox)

‘Topping’ of trees is not only unsightly, it is also unhealthy – leaving trees susceptible to biological and environmental stresses and actually making them grow faster and use more water.

For more information on why ‘topping’ is bad for trees, click here.

The Best Palo Verde Tree Variety

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I don’t have a favorite tree….I actually have quite a few favorites.  But, if I had to pick one that I like most of all, it would be the ‘Desert Museum’ Palo Verde (Parkinsonia x ‘Desert Museum’).

Palo Verde tree

Remarkable Hybrid Origins of the ‘Desert Museum’ Palo Verde

This Palo Verde is natural hybrid, resulting from 3 other Palo Verde tree species – Mexican Palo Verde (Parkinsonia mexicans), Blue Palo Verde (Parkinsonia florida) and Little Leaf Palo Verde (Parkinsonia microphylla) trees.

I have grown this tree in commercial settings as well as in my own landscape with great results.

Palo Verde tree

Best Qualities of the ‘Desert Museum’ Palo Verde (Parkinsonia x ‘Desert Museum’)

1. Drought Tolerance

The ‘Desert Museum’ Palo Verde is renowned for its exceptional drought tolerance. This hardy tree thrives in arid desert conditions, making it a perfect choice for water-efficient landscaping.

2. Striking Aesthetic Appeal

With its vibrant yellow flowers that burst into bloom during the spring, the ‘Desert Museum’ Palo Verde is a visual delight. Its green bark adds to its aesthetic charm, making it an iconic feature in any desert landscape.

3. Low Maintenance

This desert tree requires minimal maintenance, making it an excellent choice for homeowners and landscapers looking for easy-care options. Its adaptability to harsh desert environments means less fuss and more enjoyment.

4. Fast Growth

The ‘Desert Museum’ Palo Verde is thornless and known for its relatively fast growth rate. It quickly establishes itself, providing shade and beauty to your landscape in a shorter time compared to many other trees.

5. Long Blooming Season

With a lengthy blooming season extending from late spring through early summer, this Palo Verde tree provides an extended period of vibrant yellow blossoms, attracting pollinators and adding life to your garden.

6. Wildlife Attraction

This tree attracts various wildlife, including birds and pollinators, making it an excellent choice for creating a biodiverse and vibrant ecosystem in your yard.

7. Low Water Requirements

Ideal for water-conscious gardeners, the ‘Desert Museum’ Palo Verde has low water requirements once established, reducing the need for irrigation and conserving precious water resources.

8. Heat Tolerance

It thrives in scorching desert heat, maintaining its vitality even during the hottest summer months, ensuring a consistent and appealing appearance throughout the year.

9. Pest and Disease Resistance

This Palo Verde variety is relatively resistant to common pests and diseases, reducing the need for chemical interventions and promoting an eco-friendlier garden environment.

10. Versatile Landscaping

Its versatility allows it to be used in various landscaping settings, including as a shade tree, focal point, or as part of a xeriscape design, adding both beauty and functionality to your outdoor space. ‘Desert Museum’ Palo Verdes do great in full sun and areas with reflected heat such as a parking lot or in a west-facing exposure.

A Palo Verde Tree That Rises Above the Rest

I love how beautiful flowers in spring, when they bloom.  I also think they are pretty when they blanket the ground.

If you are somewhat of a neat and tidy gardener, then you may not enjoy the flowering season as much as I do.

Don’t waste your money on a large-size tree. Because they grow fairly quickly, a 15-gallon is a good size to start out with. Once planted in the ground, a 15-gallon will grow more quickly then a larger-size container. The reason is that smaller trees are younger and handle transplant stress better.  So save yourself money and go with the smaller tree.

My Desert Museum Palo Verde and an Unfortunate Event

Trees and Shrubs for a Neglected Desert Garden Area

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Trees and Shrubs for a Neglected Area

In my last post “A Long Forgotten Area Ready for Transformation”, I told you that I would share what plants I was going to have put in this neglected area.

Criteria for Plant Selection

The selection of these plants has been guided by specific criteria:

  1. Personal Experience: Many of these plants have thrived in my own home garden or in landscapes I’ve overseen.
  2. Low Maintenance: I’ve opted for varieties that require minimal upkeep.
  3. Drought Resistance: These plants are well-suited to dry conditions.
  4. Year-round Beauty: The chosen plant palette guarantees a vibrant display of colors throughout the year, with at least one plant in bloom at any given time.

Trees for the Area

So are you ready to see what I chose?

Let’s start with the trees…

Desert Willow (Chilopsis linearis)

The area has two large Foothills Palo Verde trees along with a Wolfberry tree, so I chose one other type of tree to add.

Desert Willow

Desert Willow (Chilopsis linearis) is one of my favorite desert trees.  It is not a true willow, but is named for the fact that its leaves are willow-shaped.

Colorful flowers appear throughout the summer that add a vibrant punch of color to the landscape.

Hardy to zone 6, Desert Willow requires well-drained soil and full sun or filtered shade.

Shrubs for the Area

Now for the shrubs…

Valentine Bush (Eremophila maculata ‘Valentine’)

Valentine Bush

Valentine Bush (Eremophila maculata ‘Valentine’) is my favorite shrub of all time. I will never forget the day when I was first introduced to this red-flowering shrub, by Mountain States Wholesale Nursery.  It was 1999 and I was a horticulturist fresh out of college.

I was given 2 Valentine shrubs from Mountain States to plant in the landscape area I managed.  Ever since then, I have been hooked.

Trees and Shrubs

Red flowers appear on this shrub, beginning in January and lasting until April.  If you haven’t noticed it before, there isn’t much blooming in winter, which is one of the reasons I love Valentine.

The foliage is evergreen and Valentine are hardy to zone 8.  Better yet, they only need to be pruned once a year – in spring after flowering.

Plant in full sun and well-drained soil.

For more information about Valentine, check out my post about this great plant.

Baja Ruellia (Ruellia peninsularis)

Baja Ruellia

My second choice for shrubs is Baja Ruellia (Ruellia peninsularis).

Now, this isn’t its rather invasive cousin Ruellia (Ruellia brittoniana), pictured below…

Trees and Shrubs

Baja Ruellia is what I like to think of as a smaller version of Texas Sage species (Leucophyllum sp).  It doesn’t get as large and has a longer flowering season then Leucophyllum.

Trees and Shrubs

The flowers of Baja Ruellia are tubular and appear spring through fall, with the heaviest bloom occurring in spring.

The foliage is light green and rarely suffers frost damage in our zone 9b climate.  Hardy to zone 9, Baja Ruellia should be planted in full sun and well-drained soil.

Silvery Cassia (Senna phyllodenia)

Silvery Cassia

The third shrub for this area will be Silvery Cassia (Senna phyllodenia).  This Australian native does very well in arid landscapes.

The silvery foliage will provide contrast to the darker greens present in the landscape.  Evergreen to 20 degrees, this shrub flourishes in zone 9 landscapes.

Yellow flowers appear in late winter and into spring.  Pruning is needed after flowering, to remove seed pods in managed landscapes.

Like the other shrubs, Silvery Cassia enjoys full sun and well-drained soil.

Autumn Sage (Salvia greggii)

Autumn Sage

The smallest shrub for this area will be Autumn Sage (Salvia greggii).  This plant is hard to zone 7, so remains evergreen during winter here.

Flowers appear fall through spring in the low desert.  The most common colors are red or pink, although there are other colors such as white, lavender and peach. 

I like to use Autumn Sage around trees like Palo Verde, where the filtered shade shelters it from the intense summer sun.  I first saw them planted around a tree at the Desert Botanical Garden and I really liked the way it looked, so I have repeated this design in many of my landscapes.

The Autumn Sage above, was planted by me around a Foothills Palo Verde about 12 years ago and they are still going strong.

I still have perennials and accent plants to show you that I have included in the design and I’ll share them with you next time.

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An Update on my Family

Life around our household has been busy lately….

School is back in session (for which I am extremely grateful for 😉

My son Kai, has ditched his wheelchair for a walker and will soon be able to walk without it.

AND

My daughter, will soon come home after leaving 5 months ago for the Navy.  She is graduating from her Equipment Operator School next week and will be an official ‘SeaBee’.  She will be on leave for 2 weeks before she reports for combat training in Mississippi, where she will be stationed for a month.

The BEST news is that her permanent base will be in Port Hueneme, which is where she wanted to be.  What is even better for us, is that it is in Southern California, just 7 hours from home!!!

We are getting ready to celebrate her homecoming, which I will share with all of you 🙂

A Tale of a Street and Two Trees…

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Last month as I was leaving from a landscape consultation, I took some time to drive by a few of the landscapes in the neighborhood.  

I immediately noticed that quite a few people had Olive trees growing in their front yards.

Olive tree

Olive tree

There was a large difference in how some of the homeowners pruned their Olive trees…

Olive tree

Believe it or not, both of the trees pictured above are the same type of Olive tree.

Some people like to formally prune their Olive trees while others like theirs to grow naturally.

Which one would you prefer?

Olive tree

OR

Olive tree

I know which look I prefer and it is much healthier for the tree and much less maintenance.

How about you?

Which style of pruning do you like – formal or natural?

Knit Scarves for Trees?

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Last Saturday was a day that we had long prepared for.

My husband and I had spent countless hours sitting alongside my youngest daughter, Gracie, helping her practice for her piano recital.

She was nervous, but looked so cute in her new dress and shoes.  

my youngest daughter, Gracie

The recital was held at the Mesa Arts Center and Gracie was playing along with her entire class.

As we were waiting for our turn to go inside, I saw something rather unusual in the distance.

The Mesquite trees looked rather colorful.  So, I walked a bit closer….    

knit scarves

No, my eyes weren’t deceiving me.  These trees had knit scarves covering parts of their trunks.

Knit Scarves for Trees

Now, I like to knit scarves for loved ones – but this was the first time that I had ever seen them on trees.

Knit Scarves for Trees

Even the Pine trees had colorful, knit scarves.

I couldn’t imagine why anyone would spend so much time knitting scarves and then ‘sewing’ them around tree trunks.

The trees don’t need protection from the cold.

I needed some answers, because I was pretty sure that they didn’t cover this in my Trees class in college or when I took my Certified Arborist exam.

I spotted a security guard walking nearby and asked him why the trees had knit scarves.  He explained that the trees were the focus of a group to beautify the urban landscape.

What they did is referred to as ‘Yarn Bombing‘, which is described as “The Art of Knit Graffiti.”

‘Yarn Bombing’ is occurring in urban areas throughout North America in an effort to add beauty to urban areas.

Well, I must admit that I thought the trees looked quite nice.

Knit Scarves for Trees

But, I think they might get a bit ‘warm’ as the temperatures begin to rise 😉

They will soon be taken down, so if you live nearby – stop by before the ‘knit graffiti’ is taken down.

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While we were at the recital, we got our first phone call from my daughter, Rachele, who is away at basic training for the Navy.

It was so good to hear her voice!

She is homesick and is trying hard not to be discouraged.  She has finished one week of basic training and is learning how to do things “the Navy way”.

Rachele joined up with a division that had already been there a week before and needed a few more recruits.  So, she has less time to learn how to do things.

Learning how to make their beds and folding clothes a certain way is hard and they come around with a ruler and if you are 1 cm off, you get in trouble.

I can see why this would be hard for her, since most of her clothes never made it into her dresser at home 😉

It has been cold there (outside Chicago) and they have three different jackets and knit caps that they wear when they have to march from building to building (2 miles).

She was given good advice before she left by her then boss, who is a retired Army colonel.  He said to do your best to blend in and don’t volunteer for anything.  It just makes basic training that much harder.

So far so good, she said.  Her RTC doesn’t know her name, which is supposed to be good.

She has passed her swimming test along with many of her other physical tests – so that is good news.

The recruits aren’t allowed to talk to each other.  But, some try to talk to each other at night after lights are out.  However, some get caught and have to do extra exercise.

We are doubling up on our letters to keep her spirits up.

From what we hear, everything she is experiencing is normal, including the homesickness.  It is supposed to get better around week 4, once they start to get used things.

As for me, I was a weepy mess after I spoke to her.  I do miss her so much.  But, I believe that she will make a wonderful sailor 🙂  

A Tree Given a ‘Second Chance’ Arises…

Some of you may recall me telling you about a young tree that had suffered terrible frost damage during the winter of 2011.

The tree was located at Double S Farms, which is where my mother, my sister and her family live.

terrible frost damage

This Sissoo (Dalbergia sissoo) tree had turned brown and ‘crispy’.  We waited until June to see if there would be any green growth to show us that it was alive.

The entire tree died, except for a little ‘sucker’ that started growing up from the base.

I wrote about this back then in, “Second Chance for a Frost-Damaged Tree”.

My brother-in-law and I cut off the dead tree (the entire part we are holding in our hands in the photo above) and staked up the tiny sucker, hoping that it would grow…

terrible frost damage

And now, just 14 months after we removed the frost-damaged tree, this is what the single sucker has grown up too…

Posing by the tree with my sister's new 3-legged dog, Johnny

Posing by the tree with my sister’s new 3-legged dog, Johnny.

It is hard to believe that just over a year ago, there was nothing but a single tiny branch growing from the base of the tree that had been killed by frost.

The majority of the time, people simply dig up their frost-damaged tree and start over with a new tree.

I recommend waiting a few months to see if there is any part of the tree that is still alive.  Often, they will grow a few small branches from the base, even if the rest of the tree is totally dead.

Select a single small branch and remove the dead tree and the other small branches – you want to concentrate your energy on a single branch (sucker) to grow into a new tree.

You may be wondering, isn’t it easier to just start over and plant a new tree?

The answer is “no” for a few reasons:

1. It is wasting your money buying a new tree that you may not need.

2. Save yourself the extra labor of having to dig up your old tree and plant a new one.

3. Your little branch (sucker) will grow faster then a new tree will.  The reason for this is that it already has a large established root system from the original tree. A new tree does not have a large root system and has to spend a lot of time to grow roots.  Until a tree has a good root system, the top will not grow as quickly as a tree that already has established roots.

**And so, next winter (I realize it is hard to think of winter in the middle of August), if your tree is unfortunate enough to suffer extensive frost damage – don’t remove it right away.

You may be able to save it and have a beautiful “new” tree in its place.

A Tree Given a Second Chance…

Last winter, we suffered a severe cold snap.  Okay, for those of you who live in more northerly climates, it wouldn’t seem all that cold to you perhaps.  But, we had temps that ranged in the low 20’s for three days in a row, which is definitely below normal for us.

As a result, many trees and plants that normally stay green in the winter, suffered severe frost damage.  That included my mother’s young Sissoo tree (Dalbergia sissoo).

frost damage

Frost damage

I wrote about her tree and how the top died back to the ground.  However, there were some new growth coming up from the bottom.  So instead of taking out the tree, we opted to cut off the dead portion and let one the new growth take over.

frost damage

We re-staked the little tree and waited to see how it would do.

That was in the beginning of June.

Now, just 4 1/2 months later, look at it now…

Sissoo tree

Doesn’t it look so much bigger?

That’s because it is.

Why has it grown so quickly?  Well, that is because it had a great root system – actually the root system of a grown tree, so it had many resources to help it to grow quickly.

Sissoo tree

It is still hard to believe how quickly it grew.  But, we are so happy with the decision to give it a chance instead of buying a new tree.

Sissoo tree

If we had planted a new tree, it would never have grown so quickly.

So, next time you have a frost-damaged tree, wait a few months to see if there is any re-growth – even if it is on the bottom.

You never know, it might end up with a fast-growing tree and save yourself some money at the same time 🙂  

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5 days and counting until my daughter’s due date.  We had a ‘false alarm’ on Monday.  But, I guess our little granddaughter wasn’t ready to come yet 😉

Ficus Trees….Too Much Hassle?

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For quite some time, I’ve been considering writing this post. I’ve hesitated due to the overwhelming affection people have for ficus trees (Ficus nitida). While the benefits of planting ficus trees are apparent. They have lush beauty and dense shade that are particularly valuable in desert environments. There are a few considerations to bear in mind before incorporating them into your landscape.

At first, the benefits of planting a Ficus tree are obvious. They are lush, beautiful and provide dense shade, which is sometimes scarce in the desert.

The Pros and Cons of Ficus Nitida Trees: What You Need to Know

So what’s the problem with having a Ficus tree? Well, there are a couple of things that you should be aware of before you plant a Ficus tree.

One of the primary challenges with Ficus trees is their vulnerability to frost damage. This is especially concerning in low desert regions when temperatures drop below freezing. This concern becomes even more pronounced during stretches of consecutive freezing days.

Frost-Damaged Ficus nitida with extensive browning and damage

Photo: Frost-Damaged Ficus nitida

This past winter, we experienced a three-day period of temperatures in the low 20s. The impact on local Ficus trees was unmistakable. A mere drive through any neighborhood allowed me to distinguish, even from a distance, who had Ficus trees and who did not. The extensive presence of ‘brown’ trees gave it away.

After the return of warmer weather, many Ficus trees sported trimmed branches. This results in a shorter appearance due to frost damage mitigation (see image below).

Ficus tree that had frost damaged with larger branches removed.

Photo:Ficus tree that had frost damaged branches removed.

Growth Size and Control

The second challenge stems from insufficient research regarding the potential size of Ficus trees. Individuals often find themselves ill-prepared when the charming shade tree they planted rapidly becomes an overwhelming presence. Trees often seem to engulf their homes.

Young Ficus Tree

Photo: Young Ficus Tree

They are soon caught unprepared when the pretty, shade tree that they planted soon grows so large that it almost seems like it is ‘eating’ up the house….

Mature Ficus Tree in front of suburban home

Photo: Mature Ficus Tree

What to Consider When Planting Ficus Trees

If your heart is set on having a Ficus tree grace your garden, go ahead and acquire one. Just remember that some winters might result in frost damage, temporarily affecting the tree’s appearance until new branches emerge. To ensure a successful experience with Ficus trees, keep the following points in mind:

  1. Proper Placement: Exercise caution when choosing a planting spot. Allow ample space for the tree to reach its mature dimensions without infringing on your house. Additionally, avoid planting near patios and pools, as the tree’s shallow roots can pose problems with insufficient watering. Ficus trees can attain heights of 30 to 50 feet and widths of 40 feet.
  2. Alternatives to Consider: While sissoo trees (Dalbergia sissoo) might appear to be an attractive alternative to Ficus, they also come with their own set of considerations.
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Sissoo Trees as an Alternative

Sissoo trees, resembling Ficus trees in appearance, exhibit greater frost tolerance. Despite their appealing features, it’s crucial to exercise caution when integrating sissoo trees into your landscape.

Some people look to sissoo trees as an alternative to ficus – BUT, this isn’t advisable either.

Sissoo Trees look more like a traditional northern park tree

Photo: Sissoo Tree

The sissoo tree (Dalbergia sissoo) is similar in appearance to the ficus tree. They do however have greater tolerance to frost.

Like ficus trees, sissoo trees do grow quite large but I no longer recommend them for average size residential landscapes. The photo of the tree above was taken four years after it was planted from a 15-gallon container. It rapidly grew even larger.  This tree made it’s debut in the Phoenix area about 15 years ago. It has become quite popular for its lush green beauty.

While sissoo trees flourish in larger outdoor areas such as parks due to their enhanced frost resilience, they present potential challenges for average-sized residential landscapes. Despite their initial popularity for their lush green beauty, their invasive root systems can wreak havoc on sidewalks, patios, pools, and block walls. Moreover, their eventual size can dwarf the landscapes they were intended to enhance.

Sissoo Trees can grow very large.

Photo: 3 Sissoo Trees

Careful Planning is the Best Approach for Ficus or Sissoo Tree Placement

The allure of Ficus nitida trees is undeniable, but careful planning and consideration are necessary to ensure a harmonious coexistence between these magnificent trees and your landscape. Understanding their susceptibility to frost damage and their potential for significant growth is vital for making informed decisions.

While sissoo trees can be a reasonable alternative, they too come with their own set of challenges that need to be weighed carefully. Ultimately, choosing the right tree for your outdoor space involves a blend of appreciation for aesthetics and awareness of practicality.