The time has finally arrived!  Summer temperatures are but a memory and fall is here! 

Every year we wait for the end of summer so we can start adding plants in the garden. The only question is what plants will I add?

The possibilities are endless…    

add new plants

 Purple Lilac Vine (Hardenbergia violaceae)

The signs that fall in the desert may not be as evident as in other parts of the county, yet they are here.  Elongating shadows, cooler evening temperatures along with increased plant growth and flowering are clear signs that the heat of summer is fading and cooler temperatures are on their way.

add new plants

 Blackfoot Daisy  (Melampodium leucanthum)

October and November are the best months in which to plant most types of plants in the desert.  The reason for this is that plants use the cooler weather in which to grow a healthy root system so that by the time that the summer arrives, they are ready to handle the stress of the intense heat.

add new plants

 Parry’s Penstemon  (Penstemon parryi)

Most trees, shrubs, perennials, and succulents can be planted now.  Stay away from planting palms, bougainvillea, lantana and other plants that suffer frost damage during the winter months.  They do best when planted in the spring.

add new plants

 Chaparral Sage   (Salvia clevelandii)

As in all climates, be sure to plant correctly.  Dig a hole three times as wide as the root ball but no more profound than the root ball.  This will allow the roots to grow outwards more quickly.  

When growing native plants, you do not need to add any amendments to the hole as this can cause the roots to just stay in place, enjoying the nutrient-rich soil, instead of venturing out into the regular soil.  If you do decide to add amendments to the soil, be sure to incorporate them well with the existing soil.   

Newly installed plants will initially require more water than established plants, so be sure to adjust your watering schedule accordingly.

Bower Vine

 Bower Vine (Pandorea jasminoides)

So visit your local nursery and get planting! 

Fall Planting: How to Select Plants

drought tolerant

Globe mallow (Sphaeralcea ambigua) brings a unique “cottage-garden” feel to the desert plant palette along with some surprises. In spring a flush of beautiful flowers are produced that will cause people to stop in their tracks. After that, globe mallow will bloom off and on throughout the summer and fall.  

This shrubby, perennial is native to the Southwestern areas of North America where it is found growing along washes and rocky slopes. They grow quickly and reach approximately 3 ft. X 3 ft. in size. Globe mallow is cold hardy to about 20 degrees F.

drought tolerant

Drought tolerant

Although most globe mallow plants produce orange flowers, they are available in other colors including pink, purple, white, red and shades in between. At the nursery, you will usually see the orange flowered variety available. However, some growers are beginning to stock selections of globe mallow in different colors. But buyer beware; unless specially marked or blooming, you don’t know exactly what color flower you will end up with make sure if you want a certain color to check for mark.  

Often, the surprise occurs after you plant them and wait to see what color the flowers will be. I bought four globe mallow, out of bloom, for my garden and ended up with one red, two pink and one white. For those who do not like surprises in the garden, you can wait and buy them in bloom in the spring.

drought tolerant

USES: Globe mallow attracts hummingbirds as well as butterflies. They serve as a colorful backdrop for small perennials or small cacti. Consider planting with any of the following plants for a colorful desert flower garden – penstemon, desert marigold, ruellia, and blackfoot daisy. This beautiful but tough plant does best in full sun and performs well in areas with hot, reflected heat. Do not plant in shady areas as this will cause them to grow leggy.

Globe mallow do self-seed, and the seedlings can be moved and transplanted in the fall if desired. They are used frequently for re-vegetation purposes because they grow readily from seed.

Globe Mallow

MAINTENANCE: This pretty perennial is very low-maintenance.  No fertilizer or amendments to the soil are required. Prune once a year to approximately 6 inches to 1 ft. after it has finished blooming in late spring/early summer, which will help to prevent them from self-seeding, maximize future blooming and minimize unproductive, woody growth. Globe mallow is not the type of plant to repeatedly shear into a formal shape. When pruning, wear gloves and long sleeves since the tiny hairs on the leaves can be irritating to some as well as an eye irritant.

Once established, globe mallow is quite drought-tolerant, but will require supplemental irrigation for the best appearance and flowering. My globe mallow plants are connected to my drip-irrigation system and do very well when watered three to four times a month, spring through fall.

Globe Mallow

ADDITIONAL FACTS: Historically, globe mallow were used by Native Americans for medicinal purposes such as treating diarrhea, sore throats, eye diseases as well as skin disorders. Their roots were used for upset stomachs and poultices were made for treating swollen joints and broken bones.

*Have you ever grown globe mallow?

Fall is Here! Time to Start Planting!

santa rita purple prickly cactus

Exploring the Beauty of Prickly Cactus

Do you like prickly cactus? I have a few favorites, one being the Santa-Rita Prickly Pear (Opuntia violaceae var. santa rita). The color contrast of their blue-grey pads and the shades of purple are so striking in the landscape.

The Santa-Rita Prickly Pear: A Stunning Accent Plant

The Santa-Rita prickly pear is a captivating addition to any landscape. Its blue-grey pads and vibrant shades of purple create a visually striking contrast. Not only is this cactus aesthetically pleasing, but both its pads and fruit are edible (though you may want to remove the spines first). Cold temperatures and drought conditions intensify the vivid purple color of this remarkable cactus.

Native Plant Beauty of the Southwest

Native to the Southwestern regions of North America, the Santa-Rita prickly pear can reach impressive dimensions, growing as large as 6 feet by 6 feet. However, if you prefer a smaller size, careful pruning at the junction where the pads connect can maintain a more manageable shape.

prickly cactus in full bloom

Blossoms and Wildlife with Prickly Cactus

In spring, the Santa-Rita prickly pear graces the landscape with lovely yellow flowers that later give way to red fruit during the summer months. Keep in mind that javelina, rabbits, and pack rats are occasional visitors that might nibble on the pads, while pack rats ingeniously use the pads to build their homes.

Handle with Care: Dealing with Spines and Glochids

Prickly pear pads are covered with clusters of 2″ spines and tiny spines known as glochids. Glochids are especially irritating to the skin and easily detach from the pad, making them challenging to remove. When handling these prickly cacti, use multiple layers of newspaper or a piece of carpet to protect your hands. Avoid gloves, as glochids can render them useless.

Removing Glochids Caused by Prickly Cactus

If you encounter glochids with prickly cactus, there are different methods to remove them, including applying Elmer’s glue, allowing it to dry, and then peeling off the glochids. However, many find greater success using duct tape for a more efficient removal process.

close up of prickly cactus

Versatile Uses in Landscaping

Beyond being a landscape accent, the Santa-Rita prickly pear serves as an excellent screen. Surprisingly, it can thrive in containers as well, although it’s essential to keep them away from high-traffic areas. These resilient cacti flourish in full sun or light shade and well-drained soil.

Low-Maintenance Prickly Cactus Beauty

Santa-Rita prickly pears are incredibly low-maintenance plants. When pruning, use tongs or newspaper to handle the trimmed pads. While they are highly drought-tolerant, occasional watering during the hot summer months, especially in the absence of rain, can enhance their appearance. Shriveled pads signal acute drought stress, so a little extra water can work wonders.

santa rita prickly cactus disease

Addressing the Cottony Mystery on Prickly Cactus

Some might mistake white, cotton-like areas on the pads as a fungal infection, but it’s actually caused by a small insect known as cochineal scale. Removing this cottony mass is simple—just spray it off with a strong jet of water from the hose.

pad cactus purchased at garden center

Propagation: A Simple Guide

You can propagate Santa-Rita prickly pear cacti with ease. Simply cut off a pad that is at least 6 inches tall, let it callus upright in a shady, dry spot for about two weeks, and then plant it with the cut end down.

Plant with the cut end down, do not water for the first month because the bottom is susceptible to fungal infections. After the first month, water every 2 – 3 weeks until established. 

Timing Matters

Planting in the summer requires shade until the cactus is established (approximately three months). However, it’s often advisable to wait until spring when the soil warms up for planting, especially in regions with cold winters.

Renewed Growth: Pruning and Propagation

For those with established Santa-Rita prickly pear cacti, you can rejuvenate growth by pruning or starting anew. Simply remove the cactus, cut off some pads, and replant them in the same location. Many have embraced this method and have been delighted with the results.

An Interesting Historical Fact

The Aztecs would cultivate prickly pear cactus infected with cochineal scale because the insects secrete a dark red dye with crushed. This was used to dye cloth. The Spanish exported this dye from Mexico back to Europe where it was used to dye royal garments and British military uniforms. The dye was highly valued by the Spanish, next to gold and silver. It takes 70,000 insects to produce 1 pound of dye.

*This is but one of many beautiful prickly pear species available to the home gardener. Do you have a favorite species of prickly pear cactus?

summer is beginning

There are some signs that summer is beginning to fade and that fall is around the corner.  The stress that the high temperatures of summer bring has caused many plants to slow down their growth.  

However, the slightly lower temperatures in September bring on a flush of new growth for many trees, shrubs, and succulents in the garden.  I enjoy being out in my garden this time of year and seeing many of my plants rejuvenated.

With the somewhat cooler temperatures, I am now seeing many gardeners venturing outside and taking stock of the condition of their landscape.  Fall is a busy time in the desert garden because it is the ideal time to install many types of plants, which will be discussed in a separate post in early October.

summer is beginning

SHRUBS: I just finished lightly pruning my ‘Rio Bravo’ sage (Leucophyllum langmaniae).  Summer flowering shrubs that are cold-hardy look their best when lightly pruned at this time to help reign in rangy, sprawling growth. This should be only done with hand pruners only.  Do not use a hedge trimmer and shear your shrubs.  They should have a pleasing natural shape when you are finished.  Do not prune back frost-sensitive plants at this time.

summer is beginning

ANNUALS:  Although the local nurseries are abundant with winter annuals, I don’t recommend planting them now.  The temperatures are still quite hot, and there is a good chance that they will not make it.  

In the past when mid-September came, I would load up the truck with 100+ flats of annuals to plant around the community where I worked as the horticulturist.   I would then spent the next four weeks making repeated trips to the nursery to replace dead plants that just could not handle the heat of early fall.  From then on I would wait until October to change out summer annuals and replace with winter annuals.  As a result, we suffered very little plant loss.

summer is beginning

TREES:  Mesquite and Palo Verde trees that are overgrown can be lightly easily pruned back.  Resist the temptation to heavily prune at this time.  January and February is the time for heavy pruning to occur for these trees.

summer is beginning

SUCCULENTS:  Cacti, agaves and other succulent plants do best when planted when soil temperatures are warm, which makes September a great time to install them before cooler temperatures arrive.   Prickly Pear cactus can be pruned back this month if needed.  Problems with agave may show up this time of year. 

summer is beginning

If your agave suddenly collapses, there is a good chance that they have gotten an infection with agave snout weevil.  There is no cure and the agave should be removed, it will be smelly due to the decay the weevil causes – and not just a little stinky.

One of my (least) favorite memories happened years ago when I worked as a horticulturist on a golf course.  One year, we had to remove countless agaves throughout the landscapes due to a large infestation – the smell was awful.  If this happens to your agave, do not plant another agave in the area – use another type of plant instead.

Roses

ROSES:  Roses should be lightly pruned and fertilized this month (see earlier post for details).

citrus trees

CITRUS:  Make sure to fertilize your citrus trees if you have not already done so (see earlier post for details).

NEXT MONTH – get ready for planting and wildflower garden preparation!

Large blooming palo verde an Iconic tree

  Iconic tree, Blue Palo Verde (Parkinsonia florida)

When people think of the Sonoran desert, hillsides studded with saguaro cactus and cholla often come to mind.   But interspersed between the cactus, you will find the palo verde, an iconic tree with their beautiful green trunks and branches.

An Iconic Desert Tree; The Palo Verde

The word “Palo Verde” means “green stick” in Spanish, referring to their green trunk, which is a survival mechanism in response to drought.  

Palo verde trees are “drought deciduous,” which means that they will drop their leaves in response to a drought situation.  Their green trunks and branches can carry on photosynthesis, even in the absence of leaves. 

'Desert Museum' Palo Verde planted in groups along a walkway

 ‘Desert Museum’ Palo Verde (Parkinsonia hybrid ‘Desert Museum’)

Palo Verde Trees Are Nurse Plants to Saguaro Cacti

Palo verde trees act as a “nurse plant” to young saguaro cacti by protecting them from the cold in the winter and from the intense sun in the summer.  Beautiful, yellow flowers are the product in the spring.    

Desert Museum Palo Verde Flower

 Desert Museum’ Flower

There Are Several Species of Palo Verde

There are three species of palo verde that are native to the desert Southwest; blue palo verde (Parkinsonia florida), formerly (Cercidium floridum), foothill palo verde (Parkinsonia microphylla), formerly (Cercidium microphyllum) and ‘desert museum’ palo verde (Parkinsonia x ‘Desert Museum’).

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Another species of palo verde that is prevalent in the landscape are called palo brea (Parkinsonia praecox), formerly (Cercidium praecox).  They have a dusty green trunk and branches that twist and turn.  Their cold hardiness range is around 15 to 20 degrees F.

Palo verde Iconic tree

 Iconic tree, Palo Brea

Palo Verde Landscape Uses

Palo verde trees serve as beautiful specimen trees where their green trunks, branch structure, and flowers serve as an attractive focal point in the landscape.  They are drought tolerant, once established and provide lovely filtered shade year-round.  

When deciding where to place your tree, be sure to take into account that they need a lot of room to grow, mature sizes are listed below.  

Palo Verdes don’t do well when planted in grass and will decline over time.  Locate away from swimming pools due to flower litter in the spring.

Because of their more massive thorns and branching tendency to point downwards, palo brea trees aren’t recommended in areas close to foot traffic.  

Mature Sizes:

  • Blue Palo Verde – 30 ft x 30 ft
  • ‘Desert Museum’ Palo Verde – 30 ft high x 40 ft wide
  • Palo Brea – 30 ft x 25 ft
  • Foothills Palo Verde – 20 ft x 20 ft

As with many desert trees, Palo Verde trees have thorns, except for the ‘Desert Museum’ Palo Verde.  

Palo verde in bloom Iconic tree

 Foothills Palo Verde

Basic Palo Verde Maintenance

Pruning for Canopy Elevation and Structural Integrity:

Pruning Palo Verde trees in your desert Southwest garden is a crucial aspect of maintaining their health, aesthetics, and structural integrity. One of the primary objectives of pruning is to elevate the canopy, ensuring it remains well-balanced and visually appealing. This practice involves selectively trimming the lower branches to create a more elevated and open canopy. By doing so, you allow for better air circulation and light penetration, which can promote overall tree health and reduce the risk of disease.

Steering Clear of Hedging and Topping:

While pruning is essential, it’s equally vital to understand what not to do. Avoid two harmful practices: hedging and topping.

  1. Hedging: Hedging involves indiscriminate shearing or cutting of branches to create a uniform, artificial shape. This practice is highly discouraged for Palo Verde trees, as it not only compromises the tree’s natural beauty but also disrupts its growth patterns. Hedging can lead to dense, bushy growth with weaker, more susceptible branches.
  2. Topping: Topping is the severe cutting of the uppermost branches, often leaving stubs or bare trunks. This practice is detrimental to the tree’s health and stability. When Palo Verde trees are topped, they respond with a vigorous burst of new growth that tends to be weak and prone to breakage. Topped trees are also more susceptible to pests and diseases.

The Proper Tree Pruning Approach:

Instead, adopt a thoughtful and strategic approach to pruning your Palo Verde trees. Start by identifying dead, diseased, or damaged branches, and promptly remove them. This eliminates potential entry points for pests and diseases, promoting tree health.

Next, focus on elevating the canopy by selectively pruning lower branches. When selecting branches for removal, prioritize those with narrow crotches or those that cross and rub against each other, as these can weaken the overall structure.

Consider hiring a certified arborist or a professional tree service to ensure that your Palo Verde trees receive the care they deserve. These experts have the knowledge and experience to prune your trees correctly, preserving their natural form and promoting robust, healthy growth.

By following proper pruning practices and avoiding hedging and topping, you can help your Palo Verde trees thrive in your desert Southwest garden. A well-maintained Palo Verde tree not only adds to the beauty of your landscape but also provides valuable shade and habitat for local wildlife while remaining resilient in the harsh desert environment.

Palo Verde is My Favorite Tree

As a landscape manager, horticulturist and arborist, I have grown and maintained all of the palo verde species mentioned, and I truly enjoy them all.  However, at home, I have 4 ‘Desert Museum’ trees. 

In comparison to the other species, their trunks are a deeper green; they produce larger flowers, are thornless and grow very quickly in the desert.  Also, they require little, if any, tree staking when planted. Simple amazing!

Blooming Flowers

The blooming of my desert willow tree (Chilopsis linearis), is beginning to slow down.  The leaves will fall in December.  However, there were a few lovely pink flowers left.

Blooming Flowers

Also, the recent monsoon storms have caused my ‘Rio Bravo’ sage, (Leucophyllum langmaniae), to burst out in flower.

Blooming Flowers

Beautiful, magenta brachts surrounding the tiny, cream-colored flowers on my single bougainvillea shrub.

Blooming Flowers

I also love the multi-colored blooms of my lantana ‘Patriot Desert Sunset.’  They will soon stop blooming for the winter.

 red bird-of-paradise

The vibrant colors of my red bird-of-paradise, (Caesalpinia pulcherrima) add vibrant color to my garden and nectar for hummingbirds.  

In another month, many of these flowers will no longer be flowering, but until then, I’ll enjoy the view.

Yellow Bells

This beautiful plant is one of my favorite shrubs in the garden – so much so, that I have three.  Yellow bells produce bell-shaped flowers beginning in spring and lasting through the fall months until the first frost.

 Hummingbirds and butterflies are attracted to the flowers.  The vibrant green foliage and colorful flowers make this shrub a welcome addition to any desert landscape. 

Yellow Bells is a large shrub that grows to a height of 4 – 8 ft. and spreads 3 – 8 ft. wide.  You can find its native habitat in the Americas.  There are two different types; Tecoma stans angustata and Tecoma stans stans.  Visually, the most significant difference is in the shape of the leaves.  Tecoma stans stans had a broader leaf and are pictured above and below.

Yellow Bells

USES:

Because of its size, this large shrub makes a great backdrop plant.  I have used it to screen fences, sheds and also planted it up against the house.  Yellow Bells works well as a tall, naturally-shaped hedge.  This shrub thrives in full sun to filtered shade.  They do best in warm-winter areas but can be successful as a summer annual in colder regions.

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MAINTENANCE:

This shrub is relatively low-maintenance.  It will freeze back in the winter months when temperatures go below 28 degrees F.  Since it blooms on current season’s growth, all that is required is to prune back the frost damage in early spring.  Seed pods are produced and can be removed if desired, which will extend the bloom period and improve the appearance, (the seed pods do not bother me, and I do not remove mine).   After an initial application of slow-release fertilizer when planting Yellow Bells, I have not needed to fertilize further. 

**Occasionally, caterpillars will appear but can be easily removed by spraying some BT (Bacillus thuringiensis) which is an organic pesticide.

Yellow Bells

COMMON NAMES: 

There are many familiar names for these beautiful shrubs.  Tecoma stans angustata is native to the Southwestern US and northern Mexico and goes by the names Arizona yellow bells, yellow bells, and yellow trumpet bush. 

Tecoma stans stans are native to Florida, the Caribbean and parts of South America and also goes by the name of yellow bells and sometimes yellow elder.  Because of the overlap of familiar names, be sure to purchase plants based on their scientific name.

Fall Rose Tips for the Desert Garden

Saguaro cactus

Exploring the Growth of Saguaro Cactus Arms

In the realm of desert flora, the saguaro cactus stands as an iconic symbol of the American Southwest.

The saguaro cactus (Carnegiea gigantea) is a towering, tree-like cactus native to the Sonoran Desert, spanning the regions of Arizona and Mexico. It claims the title of the tallest cactus in the United States, reaching heights of up to 52 feet and boasting a substantial diameter of up to 30 inches. Despite their slow growth, saguaros have an impressive lifespan, enduring for as long as two centuries.

One of the most common questions about these magnificent cacti is, “How long does it take for a saguaro cactus to grow its arms?” There’s a prevailing belief that it requires a staggering 100 years, but let’s delve deeper into the fascinating journey of saguaro arm growth.

However, as with much plant information, this answer is not always correct, it actually takes less time for a saguaro cactus to grow its arm back in a landscape setting than it’s native habitat.  

Unveiling the Mysteries of Saguaro Cactus Arm Development

Saguaro cacti (Carnegiea gigantea) are renowned for their impressive stature and distinctive arms, making them a captivating presence in the desert landscape. However, the timeline for the growth of saguaro cactus arms is far more nuanced than the century-long myth suggests.

The Influence of Habitat and Water Availability

The primary factor influencing the rate of arm development in saguaro cacti is the availability of water. In their native desert habitat, where water is a precious resource, saguaros exhibit a slower growth pattern. It’s not uncommon for them to take between 50 to 100 years or even more to sprout their first arms.

Accelerated Growth in Landscape Settings

In stark contrast, saguaro cacti in landscape settings, where irrigation systems provide consistent moisture, tend to grow at a significantly accelerated pace. The abundant water supply encourages more rapid development, and as a result, these cacti often display their distinctive arms much earlier than their counterparts in the wild.

Regional Variations in Growth Rates

Even within the saguaro’s range, growth rates can vary based on regional climate conditions. For instance, saguaros in areas with slightly higher rainfall, such as southern Arizona near Tucson, may experience faster arm growth compared to those in drier regions of the Sonoran Desert.

The Unique Journey of Each Saguaro

It’s important to emphasize that while some saguaro cacti may begin growing arms in as little as 10 to 20 years in well-irrigated landscape settings, others may take longer. Each saguaro’s journey is unique and influenced by various environmental factors and care.

In general, a saguaro growing in its native habitat can take 50 – 100 years to grow arms. In a landscape setting, where saguaro are treated with gentle care, arms often appear much earlier.

I have had many adventures with saguaros and love seeing them in the garden landscape. They look particularly spectacular paired up with an ocotillo.

Pink Crown of Flowers

I just had to share this photo of my flowering Arizona fishhook cactus(Mammillaria grahamii) also known as (Mammillaria microcarpa).

While walking outside in the garden this morning, I caught a glimpse of pink off in the distance. As I went over to explore further, I noticed my little Arizona fishhook cactus in full bloom. I don’t have many cacti in my garden, but even if I did, this little one would probably still be my favorite. 

Fishhook Cactus

Pink crowns of flowers appear off and on throughout the summer months in response to rain much to the delight of native bees.

Fishhook Cactus

I found this little cactus growing alongside a large boulder in an area of desert that was getting ready to be graded for a new house. At the time my crew and I were digging up different types of cacti, like barrel cacti and teddy bear cholla, to relocate them around the site out of harm’s way. I received permission to keep this little one.

One of the things that I love about this little cactus is its flowers off and on during the summer months in response to rain or a small amount of water from my garden hose.

Fishhook Cactus

Look closely at the spines, you can see where it gets their common name with their fishhook shape.

Believe it or not, I can hold this cactus (carefully) without getting pricked.

During the rest of the year, this small cactus fades into the background and is hard to see.  You can find it growing underneath bursage shrubs throughout the desert.

Do you have a favorite flowering cactus in your garden?

New Perennial Discovery and a Baby