Nurse Plants and Cactus

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nurse plants

 Young saguaro cactus were peeking out from its bursage nurse plant.

As you walk through the desert, there are many opportunities to view some of the striking cacti and their unique shapes.  What is not initially apparent, are the many examples of plants helping young cacti survive.  However, if you look closely, it is all around you – desert shrubs and trees sheltering growing cacti from the harsh desert climate. 

nurse plants

 Young barrel cactus underneath a bursage nurse plant

Despite their tough, prickly appearance, cactus are quite vulnerable.  Of the thousands of seeds that are released by each cactus, only a tiny fraction grow into new cactus plants.  Most would not survive if it were not for “nurse plants.”   These plants provide much-needed protection from the sun, cold temperatures and predators (including humans).  Nurse plants also provide much needed additional moisture for the new cacti.

nurse plants

 Mammillaria microcarpa 

It is easy to walk by and not even notice the presence of the small cacti growing underneath nurse plants.  Most of the year, the fishhook cactus (Mammillaria microcarpa), pictured above, are almost impossible to see.  It is only in the spring when they are blooming that you can spot them.

nurse plants

 Hedgehog cactus outgrowing it’s bursage nurse plant.

For the smaller cacti species, bursage (Ambrosia deltoidea) most often serves as the nurse plant.  It also often serves as the first nurse plant for saguaro cacti.

Two young saguaro cacti

 Two young saguaro cacti outgrowing their creosote and bursage nurse plants

Creosote (Larrea tridentata), palo verde, mesquite or ironwood trees often serve as the nurse plants for larger species of cacti.  As it grows larger, it requires more water and nutrients from the soil, which leaves little for the nurse plant.  So frequently, the nurse plant will decline and die as you can see from the photo above.

Young buckhorn cholla emerging from its bursage nurse plant

 Young buckhorn cholla emerging from its bursage nurse plant.

So next time you have the opportunity to take a walk in the desert, look around….you will most likely see examples of this unique relationship of plants helping young cactus survive.

Drought Tolerant and Beautiful: Globe Mallow

September Gardening Tasks

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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!

September Blooms Outside My Door

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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.

Fall Rose Tips for the Desert Garden

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Fall Rose, 'Double Delight'

 Fall Rose, ‘Double Delight’

In the Desert Southwest, we are blessed with two different blooming seasons – spring and again in fall.  

While two bloom seasons is generally one more than many regions experience, roses don’t enjoy the heat of summer and go into summer dormancy.  That means that they just exist and don’t grow or bloom significantly. Their leaves may show signs of sunburn.

Fall Rose, 'Medallion'

 Fall Rose, ‘Medallion’

However, once September arrives and the days begin to grow shorter and temperatures begin to cool, it is time to lightly prune your rose bushes, which will stimulate new growth. 

Begin by pruning back 1/4 of the top growth, removing sunburned foliage and any flowers present.  

As always, prune back to an outward facing bud at an angle of 45 degrees.  Seal any pruning cuts larger than the diameter of a pencil with Elmer’s glue to prevent borers.

Fall is also time to fertilize roses in preparation for their fall bloom season.  Apply an organic fertilizer formulated for roses.  Afterward, be sure to water in well.

'Abraham Darby'

 ‘Abraham Darby’

**For those that want to go the extra step, I would recommend soil amendments such as compost and manure in addition to rose fertilizer, which results in greater growth, lush foliage and blooms over the long term.  

To do this, first make 4 – 5, six-inch deep holes around each rose, placing them at least 1 ft. from the center (I use the end of a broom handle for this).  Then apply a mixture of aged steer manure and alfalfa pellets (rabbit food) and pour into each hole.  Water in well.  

The aged manure improves the soil structure and slowly releases nutrients.  The alfalfa pellets release a type of alcohol as they break down that roses just love.

By lightly pruning and fertilizing in early fall, you’ll enjoy a fall filled with beautiful roses.

How Long Does It Take Before A Saguaro Grows Arms?

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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.

Two Iconic Sonoran Desert Plants: Saguaro and Ocotillo

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Desert Plants

The saguaro cactus is one of the most iconic plants of Arizona, (Carnegiea gigantea), it is perhaps the most recognizable trademark of the Sonoran desert with their tall arms reaching toward the sky.

Although, saguaros are only in some regions of the Sonoran desert. The vast majority are found in Arizona and Mexico. They are often found growing on the south side of the mountains due to the warmer air temperatures.

Desert Plants

Another iconic Sonoran desert plant is the ocotillo (Fouquieria splendens) with its leaf covered canes topped with brightly colored flowers. Sometimes, people, mistake ocotillo as a type of cactus, but they’re actually a type of shrub.

Ocotillo produces beautiful vermillion blooms that attract hummingbirds and their canes leaf out occasionally in response to humidity and rain.