You may see this plant around town here and there in random spots. It's lovely and adds a touch of the lush tropics into your garden. I think that these should be near a water feature, but not all of them are used in this fashion. Put them in pots or planters with some sunny shade with lots of water and they will thrive. They do need regular watering. During our freeze, they suffered some burn, but today are producing new green stalks.
Here is a brief write from Linda Strader.
"Cyperus alternifolius, known as Umbrella Plant, is a water loving tropical looking plant that can take the Tucson climate provided you give it lots of water. It is originally from Africa, and is considered a sedge, not a grass. Umbrella Plant grows in clumps, with long stalks and ‘umbrella’ like leaves on top of the stems. It grows to about 2 or up to 4 feet tall and spreads voraciously as long as it has water, so you will need to be vigilant if you want to keep it under control. It can also self-sow and become weedy. An alternative to ground planting is growing in pots, which makes it a little easier to control. If you have a water feature of some kind in your yard, the Umbrella Plant is a good compliment to a lush themed garden. It can take sun or shade." End of article. Source: http://www.examiner.com/gardening-in-tucson/plant-of-the-day-umbrella-plant