Thaumas P. Ehr, Landscape Architect

Over-pruning Desert Plants is Unhealthy!

Being in the landscape architecture and green industry for 35 years, I have always have been bothered by plants being improperly pruned. Many times I have said that our landscapes are being morphed into wastelands of pencil erasers, hatboxes, meatballs and tubes by uninformed landscape-maintenance people who have no idea what they're pruning with their electric hedge shears.


In many neighborhoods, once-beautiful desert plants have become unrecognizable.This is puzzling, given our proximity to a vast natural landscape. With more than 35,000 acres of desert parks and preserves and 200-plus miles of trails throughout the city, we are surrounded by natural Sonoran Desert.


If you've done any hiking, you know how desert plants should look in their natural environment.Yet, all too often in our Valley neighborhoods, landscapers, gardeners, property managers and homeowners have transformed the natural character of our desert plants into comical, misshapen, unrecognizable mutations.


Although coastal gardens can look beautiful with whimsical hedge shapes, doing this to desert plants is simply incompatible with our surroundings. More importantly, it erodes their health. When you create large, flattened surfaces with hedge shears, you expose the plant in many ways to our harsh climate. Our desert plants need the multiple layers they create to survive. Quite literally the roots are not proportional to the leaf surface area.

I can't tell you how many times have observed over- and improper pruning, poor plant choices and destruction of landscape plants.


Here are some of the most serious offenses I see consistently:

  • Over-pruning with electric shears of desert-adapted shrubs and groundcover, including creosote, Texas rangers, jojoba, cassia, and brittlebush.Egregious pruning of desert-adapted palm trees -- removing way too much foliage and exposing the core to sun and wind damage, and disease.
  • Over-pruning and exposing the trunks of desert trees and "lion tailing" the branches by removing too much inner growth -- leaving only tufts at the end of limbs.
  • "Pineappling" succulents, such as agaves, desert spoons, yuccas and hesperaloe, by removing more than just dead leaves -- thereby exposing the plants' inner core to exposure and disease.Improper "topping" of trees, cactuses and succulents. Besides making the plants ugly, removing the tops of trees leaves them stressed and disease-prone.
  • Many businesses fulfill city requirements for planting trees and shrubs on commercial properties, then hack back the plants to showcase their signage or inventory (car lots come to mind).
  • Unnecessary raking of gravel areas and blowing of leaf debris. Some leaf debris can be beneficial to trees and shrubs as organic mulch, while blowers only add to the cloud of dust in our city.

Is it OK that a gravel yard is not raked? Of course it is!We recognize that landscape-maintenance companies, property-management services and homeowners are not horticultural experts. But some basic guidance and education are critical to rescuing our landscapes and streetscapes.


Take a look at the problems I've mentioned and educate yourselves on proper desert-plant choices and maintenance, and demand better from landscape maintenance professionals. Homeowners may wrongly assume that highly trained plant experts are expensive to hire. In truth, they often bill for fewer hours and provide much better service.


Here are five easy things we can do to move in the right direction:

  1. Observe.Look critically at your own landscaping and neighborhood streetscapes. Ask yourself what works and what doesn't. It's easy to do what's always been done, but consider whether that's really the best way.
  2. Educate yourself.Consider taking courses, such as the Desert Botanical Garden's Desert Landscape School, or utilize the dbg.org website.
  3. Interview landscapers.If you use a maintenance service or if your community contracts with a property manager, take time to interview them. What are their professional qualifications or certifications? Provide feedback and hold them accountable for instituting best horticultural practices.
  4. Step back.Consider stopping normal pruning for a while in selective areas and let the plants grow naturally. See what happens and evolves, then re-evaluate your landscape.
  5. Demand standards.Look for truly qualified professionals with such certifications as the International Society of Arboriculture, Desert Landscape School or Arizona Landscape Contractors Association. These professionals are held to high standards, and their work should reflect that.

In the long run your landscapes will be and look healthier and will save you money in maintenance.