The Four Seasons Gardening Webinar Series is one of the most popular horticulture programs offered by the Illinois Extension Horticulture Team. Each season, the team hosts three live webinars delivered via Zoom. Webinars are free but registration is required and space is limited. Please click on the topics below to register. Webinars are held on select Tuesdays at 1:30 p.m. Central Daylight Time.

If you need live captioning support to participate in any of these programs, please contact Andrew Holsinger at It is strongly encouraged to submit your request at least two weeks before the program begins.

Upcoming Programs 

The Nuts and Boles of Tree Identification | October 19

Illinois is home to hundreds of native and non-native tree species, but identifying them isn’t always easy. Besides leaves, bark, twigs, buds, flowers, boles, and fruit can also be helpful in identification. Gain confidence in your tree ID abilities by joining Horticulture Educator Sarah Vogel to learn how to recognize tree species based on the size, shape, and appearance of tree parts and their scientific names.

Presenter: Horticulture Educator Sarah Vogel

If you need live captioning support to participate in this program, please contact Andrew Holsinger, at It is strongly encouraged to submit your request at least two weeks before the program begins.  

Tree Root Collar Disorders | November 30

A root collar is an important area of a tree where root tissue shifts to trunk tissue. Impacts to this part of the tree can have a variety of symptoms from yellow foliage and early fall color to dieback in the upper canopy, and even tree death. Horticulture Educator Ryan Pankau will explore how to prevent, identify, and treat common tree root collar disorders.

Presenter: Horticulture Educator Ryan Pankau


Webinar Archives

Each program is recorded and uploaded to Illinois Extension Horticulture YouTube channel. To allow time for closed captioning edits, please check the YouTube channel about two weeks after the scheduled program. 

Resource Collections

Illinois Extension has a vast collection of resources addressing horticultural interests across Illinois. We recognize that home and commercial horticulturalists each have unique needs, so we've cultivated a set of resources designed to address their top concerns. From educational curriculum units to websites devoted to deeply exploring a single topic area, our resource collection represents best practices based on both proven and emerging research and the work of our professional education staff.

Composting  -  Flowers  -  Fruits and Vegetables  -  Gardening  -  Insects and Diseases  -  Landscaping