In Arizona we are lucky to have drip irrigation systems that keep our plants watered so we don’t have to worry. In the desert, many irrigation systems are initially programmed to water once a day. But some plants never adjust to daily waterings and never will. For some plants, daily watering could even be deadly.
Why isn’t my plant thriving on my irrigation system when other plants are fine?
Different plants have different needs. Many desert-adapted plants need to dry out between waterings. Drip systems tend to keep the soil moist all year round.
As a landscape designer and consultant, I see a lot of landscape plantings that are struggling because the frequency of watering is all wrong. There are a few types of plants I rarely see happy on a drip system, and it’s a real shame because they could be an incredible addition to the garden.
If you have one of these plants, and it’s never grown much or seems sickly, check the watering schedule. It can make the difference between a sad plant and a glorious accent in your landscaping.
Lavender (Lavendula spp)
There are a few species of lavender available in the desert southwest, and none of them like to have their feet wet.
Lavender is wonderful when it’s treated right. It’s fragrant, the flowers are beautiful, and they can stay in your garden for many years.
Unfortunately it’s very common to see lavenders struggling to survive in Phoenix area gardens. Usually they experience periodic die-backs until they eventually fail completely. The problem is overwatering.
In reality they would prefer to be watered much less than other flowers. There is basically no situation where a lavender needs to be watered every single day.
Geranium (Pelargonium spp)
You’ll get much better performance from your geraniums if you stop watering them every day.
They stop flowering when they get too much water, and they don’t seem to grow as fast. A geranium that is allowed to dry out a bit is a geranium that will bloom like crazy.
These plants are actually succulents! Try not to mix them with annuals that love water. Give them a deep watering twice a week and they’ll thank you for it.
These can be paired with lavender because the frequency of watering is similar.
Saguaro (Carnegia gigantea)
Saguaros get overwatered right and left. They shouldn’t be within 6 feet of an emitter, full stop.
A saguaro that is getting too much water looks like an overstuffed sausage. The ribs become less prominent as the space between them gets filled with water.
Eventually it rots and falls. Hopefully not onto anything breakable!
Water saguaros a maximum of once a month.
Barrel cacti (Ferocactus spp. especially)
Golden barrels do pretty well on irrigation-that’s part of why they’re so popular. But the native fishhooks and red barrels cannot stand regular waterings. They tend to do really poorly on drip systems.
A thriving native barrel is in well-drained soil, away from shade trees or walls reflecting heat, and only receiving extra water during really dry months.
These are the ultimate set-it-and-forget-it plants! To the point that they can’t handle much pampering.
Any doubts about your irrigation schedule? Contact me for an online consult
Most yards only need irrigation once or twice a week. But our systems are confusing and usually they get set up once at the beginning and don’t get adjusted again. It doesn’t help that there are several different systems in the Phoenix area with their own quirks.
I have experience with several including Rain Bird, Orbit, Irritrol. And I have lots of experience with landscape plants in the Valley.
Don’t hesitate to try an online consult. We can discuss your landscaping, check the condition of your plants, and even talk about recommendations for replacements and additions. This is all available for a price much lower than a house visit.
Here’s the link to my scheduler:
Paige Maloney | Arizona Landscape Designer 
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