Wild Petunia, Ruellia caroliniensis (photo on right), is a native wildflower found throughout Florida in native woodlands. This perennial is typically 6-15 inches in height. It usually grows erect and taller than broad.
Blue or violet flowers appear in the spring, summer and fall. These flowers grow in unstalked, axillary clusters of 2-4. Usually only one or two of the light purple flowers are open on any given day. The flowers have a slender corolla tube and five, petal-like lobes.
The plant grows best in part shade/part sun or full shade. It will grow best in well-drained soils and is very drought tolerant. It may be frozen to the ground in the winter but regrowth should occur from the roots. These plants may be propagated by seed or cuttings.
Wild Petunia may be confused with the non-native Ruellia squarrosa (photo on left), known variously as Blue Shade or Creeping Ruellia or Creeping Bluebell. Unlike the erect Ruellia caroliniensis, R. squarrosa, grows very low to the ground and spreads more by underground runners than by seeds. The flowers resemble those of the wild petunia but occur singularly.
Ruellia caroliniensis is the larvae host plant for the Common Buckeye, Junonia coenia, butterfly.
REFERENCES:
University of Florida Fact Sheet FPS-514, October, 1999 Ruellia caroliniensis
http://hort.ufl.edu/shrubs/RUECARA.PDF
Natives for Your Neighborhood, Carolina wild petunia, Ruellia caroliniensis
http://www.regionalconservation.org/beta/nfyn/plantdetail.asp?tx=Ruelcaro
Online Atlas of Florida Vascular Plants, Ruellia caroliniensis
http://www.florida.plantatlas.usf.edu/Plant.aspx?id=812
Jenny's Garden, Ruellia squarrosa
http://jennysgarden.com/groundcovers/RuelliaSquarrosa_ShadeCreepingBluebellWater.htm
Photos by Denny Girard