- Author: Janet Hartin
Landscape trees provide shade, cool urban heat islands, reduce interior energy use and related costs, provide habitat for pollinators and wildlife, and beautify our communities. They also help clean our environment by absorbing carbon dioxide emitted by vehicles and other producers of fossil fuels.
Taking care of our urban trees is an important way to maximize these benefits. Unfortunately, their average lifespan in our cities is less than 1/4 of their potential due to poor selection and care. You can help enact change and increase the health, longevity and canopy coverage of our urban forests by encouraging your city leaders, local non-profit organizations interested in ‘green cities' arborists, landscape architects, nursery growers, HOAs, and concerned citizens to register for our free ‘Trees for Tomorrow Start Today' workshop (via Zoom) on Tuesday, March 9, 2021 (8:15am – 3pm).
Please reach out to your city leaders and local ‘green industry' professionals to encourage their attendance and participation. While the workshop is free, registration is required through this secure link: http://ucanr.edu/u.cfm?id=264
A bevy of speakers including certified arborists, horticulturists, planners, water district personnel and other non-profit and green industry representatives will discuss the benefits of urban trees; recommended practices for their selection and care; how to avoid hazardous trees that damage property and structures; and share success stories resulting from partnerships through cities, non-profit organizations, the green industry, HOAs, and street tree committees.
A highlight of the workshop will be the opportunity for attendees to participate in breakout sessions that cut across professions and interest groups (city planners, community service directors, arborists, landscape architects, landscapers, water district managers, HOA managers, golf course superintendents, nursery growers, UC master gardeners, concerned citizens, etc.) to enact positive change regarding tree selection and care.
Thank you for sharing this opportunity to help ensure a healthy future for our children's children with your city leaders and decision-makers.
In the meantime, here are some tree care tips to ‘start the conversation' between now and the workshop:
• Select trees that perform well in your climate. The Sunset Western Climate Zone maps are more precise than USDA zones for our warmer climates. Trees should also be selected based on their adaptation to the ‘micro-climate' in each particular landscape, as well (shade, proximity to buildings, space needs below as well as above ground, soil type, water source, etc.)
• Plant trees the same depth they were in their container in holes at least 2-1/2 times wider. Do not add compost or organic matter to the hole. This practice can result in circled roots that never grow laterally out of the confines of the dug hole.
• Remove any tree ties that are cutting into the trunk or branches of your trees. If trees must be staked due to windy conditions, make sure that the ties are loose enough to allow trees to gently flex in the wind. This helps trees develop the necessary lower trunk strength and stability to support the tree as it matures. Over time, you may be able to completely remove the ties and stakes once the lower trunk becomes stronger and self-supporting.
• Keep all plants and mulch several inches away from tree trunks.
• Keep tree trunks dry. They should not come into contact with water from sprinklers or hoses.
• Regularly water newly planted trees but water mature trees infrequently and deeply. Watering too often reduces the level of oxygen in the rootzone and can lead to waterlogged soils prone to crown and root rots. During fall, trees require only about 15% of the water they require in the summer.
• Prune trees only as needed and avoid topping them. Invest in the services of a credentialed and knowledgeable professional to correctly care for your valued trees. Find a list of International Society of Arboriculture Certified Arborists in your area here: https://www.treesaregood.org/findanarborist.
UC IPM has created a diagnostic tool to help easily diagnose pest problems in your garden or landscape.
To get started using the tool, you'll first need to identify the affected plant in your landscape. Then, choose one of the four Plant Types categories that best describes it. To do this, click on the photo directly or use the +Add to my list button.
You will know the choice was made when the main photo is grayed out and your selection is listed in the left-hand column of the screen. To remove a selection, click on the red “X.”
Next, click on the Plant Names bar on the left to view a list of plants in your chosen category. Scroll down through the choices until you find your affected plant, (we'll use broccoli as an example) and then add the plant to your list by clicking on the photo or on “+Add to my list.” Note: you may also view bigger versions of images by clicking on the magnifying glass icon.
Your selection will again become grayed out and will be listed in the left column under Plant Names.
Once you've selected your plant, choose the Plant Parts bar from the left hand menu to view the plant parts choices. In our example, the crown of our broccoli has damage, so we will choose Crown. You can choose more than one plant part, but the more narrow your search, the more precise your results will be.
Once you've selected the plant part(s), click on Damage to see photographs and descriptions of damage that you may be observing on your affected plant. Choose the one that best matches your plant's damage symptoms. Our example plant (a young broccoli transplant) is showing signs of something boring into the crown.
After each selection, you will see a number in the View Results bar. The number of results will get smaller the more you narrow down your choices. Click the View Results bar underneath your selections in the left hand panel to see the diagnosis/es. If you have a handful of choices, you should be able to determine which pest or problem is affecting your plant by inspecting it and comparing the damage to the diagnosis description.
If your search brings up a large number of results, the search was too broad. Narrow down your selections when choosing plant names, plant parts, and damage. This will help you get your results faster and more accurately.
In our broccoli example, there is just one result.
The pest in our broccoli plant is the diamondback moth. We can use this page to help confirm this is our pest based on the description, photos, and damage symptoms. The results page also provides options on what to do about this pest.If none of the results seem to match the damage you are seeing, click the “Back to diagnostics” bar and try other damage symptoms. To reset your search and start over, select the Reset All bar. To return to the main UC IPM Home and Landscape page, click on "Home, garden, turf and landscape" in the green bar at the top of the page.