On 10 Jan 2004 13:28:02 GMT, pamfree (Zemedelec) opined:

Lavendar and "Butter and Eggs" (red or pink plus yellow() seem unstoppable in
zone 9. I don't know what's the cutoff point for Lantana as an outdoor
perennial, but these two have almost attained the vigor of weeds.
zemedelec

Dallas, Zone 7a is about the cut off point for lantana as a perennial.