Plant Calculator
Enter the approximate length and width of the area you will be planting and click 'Calculate' to determine how many Ruellia x brittoniana 'Katie' you will need.
*Correct and successful spacing is complex and depends on project conditions.
Ruellia x brittoniana 'Katie'
Ruellia, Katie Mexican Petunia
- Compact & continuous flowers
- Heat & drought tolerant
- Hardy groundcover
- Category: Seasonal, Tropical, and Perennial Color
- Hardiness Zone: 7b
- Height: 10-12 Inches
- Spread: 12-18 Inches
- Spacing: 10-15 in
- Bloom Color: Blue, Purple
Mexican Petunia ‘Katie’ is a compact, clumping perennial valued for its violet-purple flowers, narrow deep green leaves, and tough, drought-tolerant nature. This dwarf selection of Ruellia brittoniana stays low and well-behaved in the garden, making it a favorite for borders, mass plantings, and groundcovers in Central and South Texas. It blooms from late spring through fall, attracting butterflies and providing bright color in tough sites where other plants may struggle.
‘Katie’ thrives in full sun to part shade, with the most prolific flowering in sunny locations. It is highly adaptable to heat, humidity, and poor soils, including alkaline conditions, and is also known for its tolerance of drought and occasional flooding—making it one of the few perennials that can handle a range of extremes. The plant stays compact at 10–12 inches tall and 12–18 inches wide, and spreads slowly by underground rhizomes. For mass plantings, space 10 to 15 inches apart.
In USDA Zones 8–11, ‘Katie’ is cold-hardy, though it may go dormant in winter and return from the roots in spring. In colder parts of Central Texas, mulch around the base in late fall to protect it from severe freezes. It may self-sow lightly, but it is far less aggressive than the full-size Ruellia species, making it a safe, low-maintenance option for more refined beds.