The more colorful phormiums tend to lose their color after a while and revert to plain green. Some do this faster than others. The straight species are a lot tougher and more vigorous, and live longer than the hybrids. The color is most beautiful if given part shade to avoid bleaching of the foliage. They can get by once established on little water, but they do need some. They always get bigger than you think they will get. Make sure they have enough space! They can get HUGE, I mean HUGE, 10x10' if they revert or if they are the species. Here the only pest to watch for is mealy bugs. They collect at the base of the plant and will kill it. You have to get in there and look and apply a systemic insecticide to get rid of them. Maintenance means cutting off the finished flower stalks and pulling off the foliage when it is dead and can easily be pulled away from the plant.

I planted one of these...several years ago and most likely a vivid color..It is now ginormous (6-7ft tall and at least 10-12' or more wide. I've had to move a couple plants and probably more... It has lost it's color..it's now primarily green and yellow with small hints of color. I can't remember what color I got but it wasn't yellow! Probably a wild pink or maroon. I just came across a review somewhere that says they do loose their color once they get big!! Damn it...here it is a huge architectural piece in the front of my house with out the color I expected..so be warned..If I remember correctly they loose the color when allowed to be themselves and grow wild..but not in pots. I live in Oregon south of Portland and everything grows big here.

They don't belong warmer than zone 8. Everyone was selling a hybrid, grown in Tampa or Orlando, that held up fairly well in zone 9, but this far south, forget it unless you plant it in the shade and water the devil out of it all summer long. But then you lose all the cool colors.

Don't recall seeing any Phormium locally, but are available from Forest Farms and other on-line/mail retail nurseries. Nolina texana can look very nice in containers. Though not sure it will thrive in full sun in north Texas. Also will eventually become too broad to grow anything around it's base in a 24" pot. Other options that come to mind are nassella tenuissima (Mexican feather grass) and muhlenbergia capillaris (gulf mulhy) which should both do okay in full sun here. Here is a link that might be useful: Phormium at Forest Farms