Seen at roadsides and in deep or open forests alike, the trillium is a common species at the Park. The flowers are composed of three petals, three sepals, and leaves in threes.

Western Trillium grows from the low elevation forest to the subalpine, and thus enjoys an extended flowering season; it is not unusual to encounter the bright blossoms from April to July.

The petals fade to maroon as they age, but this flower is unusual in having pinkish petals when first opened. This is subspecies ovatum.