Center for Landscape & Urban Horticulture
University of California
Center for Landscape & Urban Horticulture


Oak Trees on Golf Course
Welcome to the Center for Landscape and Urban Horticulture (CLUH), an information resource of the University of California Cooperative Extension (UC Cooperative Extension). The CLUH supports UC Cooperative Extension educational and applied research programs serving California's environmental horticulture industry. This site features science-based information on:


Please review our Mission Statement.


Low Water Landscape
For the latest science-based information on landscape water needs, please visit our pages under Landscape Water Conservation and Irrigation Management.




Cactus Garden LA Arboretum
Information is contributed by University of California Cooperative Extension scientists. All content is reviewed by these or other experts to assure it is authoritative and science-based. Featured are summaries of technical topics, fact sheets, newsletters, reports, commentary, and web links.



Calif. water use pie chart 2015
THE 9%: Landscape irrigation accounts for just 9% of water use in California, yet landscapes are under relentless attack as California confronts ongoing drought.  The facts presented here show how these attacks are misguided and that there are ways to conserve water without degrading landscape plantings.


Does the landscape you manage have a water budget or water conservation goal that seems impossible to meet? Read about Five Simple Steps for Conserving Landscape Water.



For Home Gardening information and resources, please visit the University of California Garden Web 

Raised Bed Gardening


What's new in Landscape and Urban Hort?

Poisonous Plants in the Landscape

Figure 1. Poison hemlock flowers and leaves. Photo by Paige Filler, Flickr.

Plentiful rainfall in California this spring created an ideal environment for many plants to thrive, including wildflowers, trees, and shrubs that desperately needed the water. However, other potentially harmful species also benefited from the unusually...

Disinfectants and Sterilizers: The Lesser-known Pesticides

Cleaning, sanitizing, and disinfectant products and microfiber towel. Photo by A. Katrina Hunter.

Did you know that disinfectants and sterilizers are pesticides? Any substance that claims to kill, destroy, prevent, or repel a pest, including germs, is considered a pesticide. So cleaning products that claim to sterilize or kill germs on surfaces or...

Another Eucalyptus Pest: The Dotted Paropsine Leaf Beetle

Figure 1. Adult dotted paropsine leaf beetle. Photo by Martin Lagerwey.

Eucalypt trees have become abundant in the California landscape, but so have the many invasive eucalypt pests that have arrived in California in the last couple decades. In the fall of 2022, yet another invasive pest was added to the hoard of...

Sudden oak death: what is it?

Figure 4. Coast live oak with limbs killed by the sudden oak death pathogen, Phytophthora ramorum, possibly spread from nearby infected California Bay laurel. Photo by Pavel Svihra.

Sudden oak death (SOD) is a disease syndrome that has killed millions of native oak trees (Figure 1) along the west coast of the United States, from Big Sur in California up to Southern Oregon. The disease may involve several organisms, but its main...

White After Labor Day?

Cochineal scales on a prickly pear cactus. Photo by Lauren Fordyce, UC IPM.

It may be after Labor Day, but some of your plants may still be wearing white, breaking that long-standing fashion “rule”! While many of us don't adhere to this old rule for our wardrobes these days, you may care about white stuff on your...

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