Dear Neil: A few years ago, I planted the tall version of purple ruellia. It’s beautiful, and it takes no care. However, it’s spreading like wildfire. It even sends runners up underground into my ...

Q: A few years ago, I planted the tall version of purple ruellia. It’s beautiful, and it takes no care. However, it’s spreading like wildfire. It even sends runners up underground into my planters and ...

I planted a few Ruellia simplex, both tall- and short-stem varieties, in January in a rectangular pot. The plants are fertilised every two weeks and get about four hours of sun daily. They produced ...