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desert-landscape

“How much water do my plants need?”

I am often asked this question by desert dwellers and my answer is always, “That depends.”

desert-landscape

There are several variables that determine how much water plants need, along with the frequency of watering.

Variables include:

  • Type of soil (clay, sand, combination)
  • What kind of plant (native plants, higher water use flowering shrubs and ground covers, succulents, etc.)
  • Recommended depth of water
  • Desert region (low-desert, mid-altitude, high desert)
  • Efficiency of irrigation system
  • Water pressure (can vary between neighborhoods)
As you can see, there is no universal watering guideline in regards to how long to water or how often.

Let’s look into the variables a little more closely to help you determine what yours are:

 

SoilClay soils hold onto water longer than sandy soil. They take longer for water to permeate to the recommended depth. The result? Clay soils need irrigation less often than sandy ones but need to be watered for a longer length of time. Phoenix area soil tends to have more clay in them while those in the Palm Springs area are sandy.

Plants – Native or desert-adapted plants need less frequent irrigation versus those that come from tropical climates. Cacti and other succulents do well with infrequent irrigation.

Water Depth – Trees need to be watered deeply while ground covers and succulents do fine at a more shallow depth – shrubs fall in between the two.

Desert Region – Where you live in the desert matters when it comes to water and your plants. The differences include rainfall amounts, when the rain falls, high and low temps, and more. Residents of low-desert cities like Palm Springs and Phoenix need to add water to their plants more often than those who live in higher elevation regions such as Tucson.

Irrigation System – The older your irrigation system, the less efficient it is. This is due to mineral build-up within the system, which affects the amount of water that comes out. Also, old drip irrigation systems tend to accumulate leaks. The average lifespan for a drip irrigation system is 10-15 years. 

Despite these differences, what is a shared characteristic is that the vast majority of desert residents water too often and not deeply enough. This is usually due to lack of knowledge and thinking the ‘more is better,’ especially in the desert.
Landscapers are generally not a reliable source when it comes to scheduling irrigation – most recommend irrigating far too often.
 
So what is a desert dweller to do?
Thankfully, there is very useful information available for homeowners to help them figure out when and how much water their landscape needs.
 
Major metropolitan areas throughout the Southwest have excellent watering guidelines available for residents. The guidelines include the regional variables we have discussed so far.
Here are helpful links based on major desert cities (click the link for the city closest to you):
Watering guidelines are just that – guidelines. Circumstances may mean that you need to water more or less often, but these guides are a useful baseline to work from.
*One final note – before you implement a new irrigation schedule, it’s important to gradually wean your plants to the new one over several weeks. The reason for this is that it allows plants to become accustomed to the new schedule.

Yes, it does take a little work to figure out how much and often to water your plants, but these guides are incredibly helpful and will guide you along the way.

Rain shaft heading straight for us.  Torrential rain began to fall just a 1/2 hour after I took this picture.

You would think that living in the desert – that we don’t get much rain.
While it’s true that we don’t get as much rain as most people, we do experience periods of torrential, summer rains.
That has certainly been true, this summer.
Actually, this week, we have had rain every day – often very heavy. 
I had a landscape consultation yesterday and the back yard was not landscaped – there was just plain dirt, which had turned to mud.
My shoes are still muddy and drying out in the garage 😉

Approaching thunderstorms as seen from Double S Farms.
My garden has enjoyed the rainfall.  I have shut off my sprinklers and drip irrigation because there is a danger of over-watering plants.

My husband is very happy with how nice our back lawn looks.  The rain and high humidity have really brought out its best.  (The entire garden is my domain, except for our lawn – that is my husband’s).
  
Unfortunately, we aren’t the only ones who have enjoyed our wet, humid summer – so have the mosquitos.  We have gone through 1/2 a bottle of repellent in just 5 days 😉

And so, as the rain threatens to fall again tonight, I will cheerfully sweep the entry and patio for the fourth time this week because I know all too soon the rain will taper off and become an infrequent visitor.

Okay, I must begin this by admitting that I have no idea what to post about today….

Maybe I shouldn’t admit this to you, but there are times when I have nothing.  I think it may be because there is so much going on in my life. 

– My three youngest kids start school on Monday (we have a modified year-round school calendar).  My daughter Ruthie, begins Jr. High and is understandably nervous.  We went shopping yesterday for some new clothes and shoes.

– We have guests arriving tomorrow from Kansas City who we will be entertaining for the weekend.  There is a very special story behind these people and my daughter Ruthie.  I can’t wait to share it with you later 🙂

– I just finished writing 4 gardening articles and have one more left to go.

– We are busy helping my in-laws each week with miscellaneous tasks around their home.  My father-in-law is continuing to suffer more debilitating effects from ALS.


However, with all of this going on, my garden is thriving.  I thought that I would share with you some summer things that you should do in your garden.  


It is from an article that I wrote earlier this month for a local community newsletter.  I hope you enjoy it 🙂

Thankfully, there is not a lot of things to be done in the garden during the hot Southwest summer, but there are some tasks that are important this time of year.  

I recommend going out into your garden during the early morning hours to do these tasks, as I do, or at dusk, once the sun begins to set to avoid the extremely hot period of the day. So, put on your hat, sunscreen, gloves and sunglasses and let’s get started.

Succulents: Cacti, agave, yucca and other succulent plants can suffer from both the extreme heat and sun of summer, especially on the side of the plant that points toward the southwest. Signs of heat damage include a yellowing of your succulents. If your succulents are not connected to your irrigation, they need to be watered to a depth of one to two feet. Larger succulents such as saguaro, ocotillo and yuccas need to be watered to three feet deep. Do this once this month and again in August. 

This can be easily done by simply placing your hose next to the plant and barely turning the water on so that the water trickles out slowly. Leave the water on for at least an hour and then check to see if you need to leave the water on for longer.

Shrubs: Make sure that your shrubs are receiving enough water. They should be watered to a depth of 2 feet each time you water. Avoid fertilizing this time of year since this creates more stress for your plants, which are struggling to handle the heat of summer. You can deadhead spent flowers from your shrubs to promote additional bloom, but avoid pruning away any foliage at this time of year. Spider mites can become a problem this time of year. Look for any tiny webs, which are a sign of these tiny mites. Controlling them is easy since they like to hide in the dust, so spray your plants every few days with water to help keep the mites from becoming established.

Trees: Avoid planting any trees this month, except for palms. Mature, established trees require deep watering this time of year, especially if they are not connected to your irrigation system. This should be done once a month in summer, watering to a depth of 3 feet. Using a hose, allow water to slowly trickle out around the drip line of the tree (where the branches end, not against the trunk) which is where the roots are located. You may need to move the hose so that you water around the entire tree. You can skip one watering if you receive 1 inch of rainfall, which replaces a single irrigation. 

As the increased humidity, (25 – 33% humidity is considered high in the desert), makes it more uncomfortable for us to go outside, it helps to keep in mind that plants just love the extra moisture even if it is only in the air around them.


**I hope you find this helpful.  I wanted to also tell you about a fabulous sight that I saw on our vacation.  I blogged about it on my Birds & Blooms blog.  



 

Baja fairy duster (Calliandra californica) is a must-have for the desert garden.  There is so much to love about this shrub.  

 
My favorite attribute is that it flowers off and on all year.  Its red flowers are shaped like miniature feather dusters.  Also, this plant attracts hummingbirds, is low-maintenance, drought tolerant and great by swimming pools because of its low litter.
 
Baja fairy duster has a vibrant red flower, which is often a color missing in the desert plant palette.  The majority of flowering occurs spring through fall, but some flowering can occur in areas that experience mild winters.  
 
It is native to Baja California, Mexico and is also called red fairy duster by some.  It is evergreen to 20 degrees F.  During some unusually cold winters when temperatures dropped into the high teens, I have had some killed to the ground, but they quickly grew back from their roots. 
 

USES: This shrub grows to approximately 4 – 5 ft. High and wide, depending on how much you prune it, so allow plenty of room for it to develop.  

 
It makes a lovely screening shrub, either in front of a wall or blocking pool equipment, etc.  It also serves as a colorful background shrub for smaller perennials such as damianita, blackfoot daisy, Parry’s penstemon, gold or purple lantana and desert marigold.  
 
Baja fairy duster can take full sun and reflected heat but can also grow in light shade.  It is not particular about soil as long as it is well-drained.
  
 Baja fairy duster in the middle of a desert landscape, flanked by desert spoon to the left and ‘Torch Glow’ bougainvillea to the right.  Red yucca is in the foreground.
 
MAINTENANCE:  As I mentioned before, this is a very low-maintenance shrub.  Some people shear this shrub, which I DO NOT recommend.  This removes most of the flowers and takes away from the natural shape of this shrub.  However, it’s size can be controlled with proper pruning.  Pruning should be done in late spring and should be performed with hand-pruners, NOT hedge clippers.
 
Baja fairy duster does require regular irrigation until established but then is relatively drought-tolerant.  However, proper watering is needed for it to look its best and flower regularly, which is what I do.  


Other than adding compost to the planting hole, no other amendments or fertilizer is needed.  Most native desert plants have been adapted to growing in our nutrient deficient soils and do best when left alone in terms of fertilizing.  I tell my clients to fertilize only if the plant shows symptoms of a nutrient deficiency.
 
So, go to your local plant nursery and get some of these beautiful shrubs for your garden.  Then, while you sit and enjoy its beauty, you can debate what you love most about it….the beautiful year-round flowers, the hummingbirds it attracts, it’s low-maintenance, or come up with your reasons.


Do you like prickly cactus?  

I have a few favorites, one being 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.  

This cactus makes a beautiful accent plant for the landscape. Both the pads and fruit are edible, (but you might want to remove the spines first ;-). Cold temperature and drought intensify the purple color.

Santa-rita prickly pear is native to the Southwest regions of North America. They can grow as large as 6 ft. X 6 ft., but can be pruned to maintain a smaller size.  Pruning is done carefully, by making pruning cuts at the junction where the pads connect.


Lovely yellow flowers appear in spring followed by red fruit in the summer months.  Javelina, rabbits and pack rats will sometimes eat the pads. Pack rats use the pads to make their homes.

The pads of the prickly pear are covered with clusters of 2″ spines as well as tiny spines known as glochids. Glochids are incredibly irritating to the skin and detach from the pad very easily. Their tips have a small barb, which makes them difficult to remove from your skin.  If you need to handle them, use a few layers of newspaper or a piece of carpet. Do not make the mistake of touching the pads with gloves because the glochids will attach to your gloves and render them useless, (I ruined a perfectly good pair this way). 
 
 **There are different ways to remove these small spines, including applying Elmer’s glue (letting it dry and then pulling them off), but many people have reported greater success using duct tape. 

 

 
USES: In addition to serving as an accent plant in the landscape, this prickly pear species can also be used as a screen. Some may be surprised to learn that they also make excellent container plants, just make sure they are not near any foot traffic areas. They do well in full sun or light shade in well-drained soil.
 
MAINTENANCE: Prickly pear is very low-maintenance plants. I always use tongs to pick up the pads that I have pruned, or you can use newspaper.  
 
Although they are incredibly drought-tolerant, watering once a month during the hot summer months, in the absence of rain, will be appreciated and will improve the appearance of your prickly pear. Shriveled pads indicate acute drought-stress.
 
 

Many people believe that the appearance of white, cotton-like areas on the pads is a sign of a fungal infection. However, it is caused by a small insect that secretes the white cottony mass, called cochineal scale.  Control is straightforward – simply spray off it with a strong jet of water from the hose – that’s it!

 
PROPAGATION: Prickly pear can be planted from seed, but there is a much easier way. Just cut off a pad that is at least 6 inches tall. Put the pad upright, in a shady, dry place for at least about two weeks. This allows a callus to form at the bottom.  
 
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.  If planted in the summer, provide shade until established (about three months). *I generally do not recommend planting in the winter but encourage waiting until spring when the soil warms up. 
 
If you have a large prickly pear, you can prune it, or you can start over by taking it out and cutting off some of the pads and plant them in the same place. Many of my clients have done this and been happy with the results.
 
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?