As an adult, Thea took some classes in traditional drawing techniques with charcoal and graphite and discovered that she could draw. After moving to Melbourne in 2001, she joined the Saturday botanical illustration classes held by the FRBG Melbourne and started to develop her understanding of botanical art and improve her techniques. She loves to experiment with new methods and materials but still regularly returns to her first love of pencil drawing.

Once retired, Thea had more time for art classes with many different teachers and helping with organising exhibitions. These include the 2011 Eternal Order in Nature exhibition and all the TABI and reFraming Nature exhibitions since then. Thea has also exhibited in every TABI since 2016.

Thea joined the Botanical Art Society of Australia committee in 2011 to help support Australian botanical artists and has been President or Vice President ever since. She has exhibited with BASA in both Sydney and Melbourne and helped organise all their exhibitions especially the first Botanical Art Worldwide exhibition in 2018 and Bountiful Botanicals, the second Worldwide exhibition in 2025.