http://iequei.notlong.com 16 May 2008 Trilliums. The white trillium (Trillium grandiflorum), also known as the wake-robin and the white lily, was officially adopted in 1937 as the offical flower of Ontario. A good choice, since this ubiquitious plant is probably the most common Spring flower thoughout Ontario, found is slightly wooded areas in decidious forests. I notice some people are growing trilliums in their gardens.