I'm Ivy. Interestingly, though, my top matches were equivalent: 80% for both Ivy and Rowan. Of course my avatar is currently a bumblebee, not a butterfly, but I guess that's a pretty close match! :-)

"In Celtic astrology, you're Ivy (not everything on the zodiac is a tree). The animal symbol that accompanies this plant is the butterfly. The ancient Druids say Ivy people are good-natured, empathetic, optimistic, and social and may have magnetic personalities. However, Ivies may be prone to indecision, disappointment, restlessness or a fear of offending others."

The Rowan 80%
The Ivy 80%
The Oak 75%
The Alder 75%
The Hazel 75%
The Willow 65%
The Vine 65%
The Holly 60%
The Elder 60%
The Birch 55%
The Reed 50%
The Hawthorn 50%
The Ash 45%