Equisetum - horsetail. And a planter is ideal. In the ground, this plant spreads like greased lightening. And much harder to remove permanently than real running bamboo.

Beautiful plant, but be very careful. It can be extremely difficult to remove from unwanted areas. A raised border planter won't necessarily be sufficient to contain spread--it can send rhizomes down and then laterally. (Picture down a raised planter and under a 3-4' concrete walkway.) If brave enough, I would put it in a solid bottomed planter with just drainage holes below, on top of solid concrete. And then be very careful with the pruning pieces. Definitely do not reuse the soil. I love the look of the plant, but don't dare introduce it into my CA garden.

Thank you both for the insight. It looks like the plant requires more water than I would like, esp. during the draught we're having in CA. So, I'll pick something else a little more draught tolerant for the planter. Thanks again!

If you are interested in the vertical look, maybe Pedilanthus macrocarpus, or one of its relatives, may work for you. I believe they come in dwarf or tall.

Equisetum hyemale is the botanical name. And this one does prefer moist, partial shade locations and wouldn't be ideal for a hot, sunny planter.

FataMorgana