The Ruellia you have is Ruellia brittoniana and it can be very invasive. In irrigated beds or areas it spreads by underground 'runners' like Bermuda grass. Each stolon or rhizome that breaks off when you pull, leaves behind a piece that sprouts a whole new plant. (This is not the same plant as Baja Ruellia - Ruellia peninsularis which is a mannerly shrub or Katie Ruellia - a dwarf.)

To control you can try any product that contains glyphosate like Round Up, Doomsday, KleenUp, etc. Apply when the Ruellia is actively growing, in other words green and healthy. You almost need to 'trick' it by watering, fertilizing and pampering and then spray. Be careful not to let the spray or drift land on your roses. I've used a piece of cardboard placed by the plants I want to keep when spraying this product.

It may take more than one application, and you want to do it in the next month or two for best control. You can always call the 800 number on the product label and ask the manufacturer for tips as well.

I hope this helps.

I am trying to get some to root. How can I accomplish this task. I broke some of them off of a friend's plant. Will they root somewhat like a coleus? I need some advice.
Or do I need the roots themselves? Please help.
Schelle

I have water-rooted some ruellia and other related-species of the Acanthus family. The also set seed very easily, tend to "pop" seed out, and sprout on their own. A few also run from their roots, depending on what species you have.

In general, they are very easy to propagate and can be somewhat invasive, depending on your climate and situation. But, they are beautiful plants, and worth checking out. Very tough and many are xeric too (I wish I could propagate or find a "desert ruellia" (not sure of the species name) to try here in ABQ.

John R. in NM

I can't stand this plant. I have put all veg. kill on them and covered the whole area with weed mesh to quarantine. They are popping up through my grass, liriope, tree roots, etc. I really think that I will forever be yanking these out of our garden.
I have been trying everything to get rid of them for half a year and nothing has worked.
Vinegar did not work. Salt seemed to work better than RoundUp. Salt is supposed to kill just about everything and it did do some damage, but not enough.
RoundUp was a waste of money - saw new growth within a couple of weeks after spraying. The all veg. kill is left to be seen. I really wanted to avoid using chemicals, but once I saw how these plants can take over....basically, once these plants are established, the roots are like a huge bowl of spaghetti deep in the ground.
AVOID using! You will be invaded. Also, they are listed as an invasive plant by the Florida Exotic Pest Plant Council. I see them being planted all around me in these new housing developments! Cities and towns should seriously consider not allowing them to be used on new permit landscapes! Homeowners that aren't gardners are really going to have problems with this plant.

Here is a link that might be useful: Florida Exotic Pest Plant Council

They can be conquered. My technique is to cut off a few stems about 2 inches above the ground (to help keep them in sight). Then use an eye dropper or Q-Tip to put concentrated RoundUp on the freshly cut stem end. You can see the liquid being absorbed into the stem, so you can put more on. Two drops has been sufficient per large stem. I have not seen any regrowth in 3 weeks time, except in stems I cut and then lost sight of and didn't therefore treat. The visible stems turn brown fairly quickly. Curiously, however, the treatment seems to only kill that stem and its' associated rhizome. I had thought that the rhizomes were interconnected but only a few seemed to be.
Where I tried earlier to dig them up I was left with many more sprouts. The rhizomes were about 8 inches below ground and seemed interconnected. I'll let that batch get big enough to treat as I described above.
The concentrated RoundUp is normally sold as a refill for their sprayers and is to be cut with water for that purpose. I put it on full strength.