are they 3 sided ? it's looks like a cactus that i have but mine gets alot of water and mine grows really fast. I don't know the name of mine either. sorry, i'm wondering why yours doesn't grow much ? do you water them full 2-3 times a week from spring till fall ?

miss daisy

They look like dragon fruit plants to me. The reason why they may not be growing fast for you, is you might need to give them something to allow them to grow upward. Mine didnt grow for me for about a year, then i put them on a trellis and they have grown over 4' in a couple months. Dragon fruit likes to grow up something. Hope this helps.
Justin

miss daisy, yes they are 3 sided. I don't think I water them very often, since I know cacti doesn't like water that much.

Justin, thanks for your info. I will move them to a bigger pot and put a bamboo trellis to let them grow up.

Can't wait to see them grow and produce flowers and fruits.... yummy....

Unfortunately, just three sided growth does not mean it is a DF (hylocereus). There are many epiphyllums w/3-sides (circus-circus and three oranges pop to mind), not to mention hylo crosses (Connie Mayer and Maiden Erleigh). Even if it is pure hylo, not all hylo are grown for fruit.

All that said, worse case scenario, you end up w/a healthy cacti with beautiful blooms. Even if it is not DF the fruit is edible, perhaps just not as good or large. These cacti are epiphytic and grow in the crotches of trees. For me loose "soil" with lots of organic matter, just make sure it drains well. Good amount of light, they do like to climb (hanging baskets ok too), no freezes.

If it is DF, they get BIG. If you have the time, you might check out Epiforums, they deal almost entirely w/epiphytes and have some seriously smart people there.

good luck,
-Ethan

for pretty DF pictures, check this site
http://www.tropicalfruitnursery.com/dragon/index.htm