Archive for May, 2012

New Florida Whitefly Website (Includes List of Trained Professionals)

Rugose Spiraling Whitefly Eggs, Juveniles, and Adults. Photo: UF Laura Sanagorski

Green industry professionals of Palm Beach County should be aware of the new Florida Whitefly website ( that contains whitefly management information for professionals, homeowners, and educators.  For professionals, this site provides access to an e-learning course  titled “Invasive Whitefly Pests of Florida”.   Following the course, an exam will be presented; professionals who successfully complete the exam will be listed on the website.    I encourage horticultural professionals who treat or plan to treat whiteflies to take the class and exam to increase knowledge, earn one CEU, and get on the list.  Individuals may look to this list to hire professionals who are proficient in whitefly management.

The Florida Whitefly website is a result of a partnership between the University of Florida (UF), IFAS Extension, Department of Entomology and Nematology, Florida Department of Agriculture and Consumer Services-Division of Plant Industry, UF/IFAS Extension-Lee, Miami-Dade, and Palm Beach Counties, Southern Plant Diagnostic Network, IPM Florida, and Pest Management University.

A score of 70% or better on the quiz earns the user one FDACS CEU in one of the following categories: Limited Lawn and Ornamental, Limited Landscape Maintenance, and Commercial Lawn and Ornamental.

Root Systems and Depth – Important Considerations for Tree Selection and Planting

Severe Circling Root System: Structural Defects that May Not be Detected Without Proper Inspection. Photo: UF Laura Sanagorski

A program was held on Monday, May 21st*, on pruning young trees for structure and selecting quality trees for planting.  We discussed the importance of evaluating the structure of trees’ trunks, canopies, and root systems.  The root system is often overlooked.

A Sound Root System: Roots Grow Away from Trunk and Do Not Circle. Photo: UF Laura Sanagorski

Prior to selecting trees for an installation, take some time to inspect the roots.  This could mean removing trees from their containers or removing excess soil from the top of the root ball.  Plants and trees, especially those grown in containers, may have several inches of excess soil on top of the root ball.  This should be removed, as you want to ensure that the topmost, or first-order root(s), is about 10% the height of the root ball above grade after planting.  Over time, the tree will settle and the topmost roots  will be at grade.  This allows the root system to grow properly, and to receive enough water and oxygen to support the growing tree.  Planting a tree too deep and/or failing to remove excess soil from the top of the root ball, is a common cause of tree decline.

Proper Planting Depth and Sound Root System. Photo: UF Laura Sanagorski

A healthy, structurally sound root system has roots that grow straight, away from the trunk, and do not circle or girdle.  Trees that have been planted too deep, or left in containers too long, may develop circling or girdling root systems.

When roots hit the impervious container, they turn and begin to circle the pot.  This can be a huge problem in the landscape: as the tree matures and the canopy grows larger, the roots continue to circle, possibly girdling the trunk.  They may not be able to support the tree – failure is a possibility.

Sometimes circling roots will be very fibrous – these can be teased out prior to planting or sliced with a sharp shovel after planting.

Correcting Fibrous Circling Root System – Slicing Technique. Photo: UF Laura Sanagorski

When circling roots have turned woody, pruning can correct these defective roots.  Pruning cuts should be made before the root turns, as new root growth will be in the direction of the root just before the cut.  I encourage you to make a commitment to planting trees with the topmost roots just above grade, and to inspect root systems prior to selection and planting.

Tree Failure Due to Circling Roots. Photo: UF Laura Sanagorski

*(This program was the first of eight in the 2012 Strengthening our Community Tree Canopy Series‘ for professionals, a project supported by FDACS and the Florida Forest Service through a 2011 Urban and Community Forestry Grant.  To learn more about upcoming topics in this series, Download the 2012 Urban Forestry Brochure here.)