April 2022 EcoQuest: Imprudent Pruning | Desert Botanical Garden


Join the April EcoQuest: Imprudent Pruning

Find and map as many examples of improper pruning as possible.

Be sure to use #imprudentpruning in the notes of your observation! This will help us sort through the observations on iNaturalist.



Any and all examples of improper pruning in metro Phoenix, including trees and shrubs, palms, cactus and agaves. Take multiple photos and include as many details as possible with observations.

This month’s EcoQuest is in collaboration with Desert Botanical Garden’s Desert Landscape School.

Desert Landscape School (DLS) is a signature program at Desert Botanical Garden, that offers professionals, homeowners and gardeners an opportunity to learn from experts about all aspects of desert landscaping. Sign up for one of the exciting horticulture and desert gardening classes today! Courses are available for online and onsite learning. Learn with DLS.

To learn how to properly prune and maintain plants, take the DLS Planting and Maintenance class, starting the week of April 18.

In nature, plants can be pruned by animals, storms, or they naturally shed branches. In a landscape setting, like homes and urban areas, pruning can be done for various reasons. Choosing the right plant for the right place should always be the first consideration. This means choosing plants that will not outgrow the space they’re in, cause problems when fully grown, or need a lot of pruning. There are multiple types of pruning -thinning, structural or raising- that can help maintain plant health, influence fruiting and flowering, provide clearance or improve aesthetics when done properly.

Imprudent pruning is asking for trouble. When pruning practices and methods aren’t carefully considered and executed, it can affect the health and life of plants. Improper pruning can damage a plant for the rest of its life. Pruning reduces and removes plant resources, creates wounds and causes plants to react in different ways. The use of dirty and dull tools also can cause damage and spread disease. Removing too much plant material at once can shock plants and weaken them. Pruning at the wrong time can reduce or eliminate flowers and fruits, reducing food sources for pollinators and wildlife.

Plants provide many benefits to people and wildlife, and help mitigate the effects of climate change. If we are planting trees in great numbers but are losing them in a few years’ time due to improper pruning and maintenance, we are negating our efforts. Mature trees are less tolerant of pruning, and we can lose them and the many benefits they provide to harsh pruning practices. It is important to maintain plants for the long-term.

Below are the top 5 most common examples of imprudent pruning. Can you find these for this month’s EcoQuest?




What is it? Literally cutting off the top of a tree, across branches with no consideration for proper pruning cuts.

Effect: Removing the top of a tree causes compounding problems. Immediately, this depletes the resources of a tree and causes an immense amount of stress. As the tree attempts to recover, multiple new branches will grow from the exposed cut stubs. These branches compete with one another, leading to poor branch connections that can eventually break. Exposed stubs can rot and lead to even more damage. Topping, especially repeatedly, is a slow death for a tree. In-depth info can be found here.

What to do instead: Right plant, right place. Selectively prune branches. Larger limbs can be pruned back to a lateral limb that is at least one-third the diameter of the limb being removed.


Lion Tailing

What is it? Removing interior branches, leaving a “tuft” of branches on the outer-most ends, resembling a lion’s tail.

Effect: Trees naturally grow in a way that evenly distributes weight. Lion tailing concentrates the weight of branches left at the top, leaving the tree’s structure compromised. Especially when combined with new growth, the concentrated weight becomes too much for the tree to handle, causing the tree to break or split. This also leaves a tree more vulnerable to storm damage.

What to do instead: Right plant, right place. Selectively prune branches. For trees that have previously been lion-tailed, allow sprouts along the lower branches to fill in and selectively prune them with time to create more stable branching.


Shrub Shapes

What is it? Also known as shearing or tipping, this is cutting the tips of branches off to shape a shrub and removing large amounts of the plant all at once. Shearing cuts are made all over, without taking the structure of the plant into consideration. Shrubs are often sheared into unnatural geometric shapes.

Effect: Removing the tips of branches stimulates growth and density. This in turn blocks sunlight to the interior of the plant, reducing its ability to photosynthesize. While the outside might look green and healthy, the inside is browning and unhealthy. This can eventually kill the plant from the inside out.

What to do instead: Right plant, right place. Selectively prune branches for size and structure, according to selected plant and desired size.


Puny Palms

What is it? Over-pruning palm trees, leaving very few living fronds.

Effect: Palm trees rely heavily on their fronds to make energy, and they typically only make a few fronds at a time. Some only make one to two new fronds a year! Removing living fronds can slow or stop a palm’s growth. Over-pruning palms also makes them less storm tolerant. Climbing spikes should not be used to climb palms to prune. Climbing spikes wound the palm tree which do not close, inviting insects and pests.

What to do instead: If you must, only remove dead or discolored fronds, never living fronds. Do not remove fronds that have a horizontal or upward orientation.


 Photos from University of Nevada, Reno.

Cactus and Succulent Chop

What is it? Randomly chopping cactus, cutting agaves to look like pineapples, trimming up or “skinning” yuccas, shearing aloes.

Effect: Excessive pruning can harm and kill cactus, agaves, aloes and yuccas. Removing leaves from agaves, aloes and yuccas makes them more vulnerable to cold and water loss. Pruning wounds plants, opening a pathway for disease and pests.

What to do instead: Right plant, right place. Agaves, aloes, and yuccas retain dead leaves and should not be pruned. Do not remove living leaves. If necessary, flowering and fruiting stalks can be removed. Cactus and succulents should be pruned at a joint or line of demarcation. Right plant, right place. Do not plant near walkways or other areas frequented by people and pets.

Does all of this sound complicated? Don’t worry, because it is! Pruning and plant maintenance is a science and takes knowledge and experience. Pruning and landscape maintenance should be done by certified arborists and landscapers with training and a strong understanding of plant biology. They know what will improve the health of your plants and help them last.

Observing plants that have been imprudently pruned can help us recognize improper pruning and the effect it has on the health and longevity of plants. We can also see if there are patterns of improper pruning in our area.

Tell your friends! Say NO to the top 5 NOT wanted!


When making observations, please be mindful of homeowners’ yards and commercial properties. Do not include identifiers of homes or businesses in your photos. That includes submitting observations with the name of a company, home address, etc.. Photos that don’t follow these guidelines will be removed and will not count for the EcoQuest..


Sources and more information:

Desert Landscape School
Trees Are Good
Leaf & Limbå
West Coast Trees
University of Nevada, Reno
Advanced Tree Health


EcoQuests are month-long challenges that are part of the larger Metro Phoenix EcoFlora project. Learn more by visiting our website.

Look for project happenings, EcoQuest announcements and more in the newsletter, project journal and on social media.

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Please do not observe indoor houseplants or pets.
For your own safety and the protection of plants and wildlife, do not trespass when making observations. Please follow all posted rules and guidelines in parks/preserves and do not enter private property.
Do not remove or move natural materials (plants, animals, rocks).
Respect wildlife (do not touch, feed, or disturb animals and keep a safe distance).

Arizona Office of Tourism: Responsible Recreation in AZ