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!

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, '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.

Saguaro cactus

In the past, people have asked me how long does a saguaro cactus arm take to grow back. The commonly held belief is that it takes 100 years before they will develop an arm.

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.  

The most critical factor in determining the timing of when a saguaro will start to grow an arm is the availability of water. Put simply, the more water a saguaro receives, the more quickly it grows. In a landscape setting where irrigation is present, a saguaro will grow much more rapidly then they do in their natural desert habitat. Saguaro cacti that grow in southern Arizona (near Tucson) grow more quickly than those in the western areas of the Sonoran desert because there is more rainfall in southern Arizona. 

A saguaro growing in its native habitat can take 50 – 100 years to grow arms. In a landscape setting, arms often appear much earlier.

 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.