I had to tackle this problem myself about a month ago----my anthuriums grow a lot during the winter and their long necks were making the entire plant way too tippy. An article I read on the internet stated that fussing with their sensitive roots would destroy the plant (ack!) and you should never do such a thing. Dang it though, I had to try *something*.

I basically decided to do an experiment: I treated it the same as an african violet with a long neck. I unpotted it, whacked off the bottom 1/3 of the rootball, trimmed off the top 1/3 of the foliage, removed any suckers, then planted the entire thing deep to cover it's neck (I put it back in the same size pot). So far the plant has been fine---it continues to bloom like CRAZY, but I do see a leaf or two beginning to yellow. I would say the procedure was a success, but I suppose there's still a chance the whole plant could collapse on me. It'll be interesting to see what other people say on the topic.

An added note: the suckers I removed and potted up separately never missed a beat---they're growing like gangbusters!

I also have a Wonderful Coworker (my nickname for her is Dawn Scissorhands), who told me to just whack off the top of the plants every now and then to keep them the right size, but I can't bear to do it. That still doesn't help with the filling in the bare bottom of the stems, either.

Here are two posts I saved off the internet, probably somewhere from gardenweb, I haven't tried it myself so no guarantees:

"I have about 25 different Anthurium andraeanum plants. They are my absolute obsession. What I am going to say is scarey and painful to contemplate. You have two options... Unpot the plant and break up the dirt. Cut the bottom of the rootball off so that you can repot the original plant further down in the pot. Or...cut the top off of the plant about 1 inch above the dirt. The bottom will re-sprout. Put the top, which likely already has air roots, in a new pot, keep watered and you will soon have two plants. They really are tough little creatures. Either way will come out fine."

And this:

"Many anthuriums in nature are epiphytic and lithophytic, they grow in the rainforest canopy clinging to the branches of trees and onto cliffsides where water drips down. But they don't live ***in***water. You can grow an anthurium mounted to lava rock/volcanic stone easily, but you musttreat it like a mounted orchid: good light, good air circulation, warmth, humidity, mist it daily, and once a week or maybe once every two weeks, add some fertilizer to the water you mist with. An orchid fertilizer would be fine. Follow the dilution directions on the box. Anthuriums that are potted in media or planted into the ground will still eventually push roots up through the soil to try to attain their epiphytic nature. If you do pot your anthurium, use a mix of well draining highly organic mix, liberally peppered with bagged wood chips, perlite, even small pieces of bagged lava rock or aliflor."

Hope that helps. Good luck!

I believe that 2nd statement is mine from an old post, Water girl.
Anthuriums, being epiphytes, will continue this behaviour (if they are HAPPY and GROWING WELL!!!!! LOL) ad infinitum. They want to get those roots out, they want to scramble over stuff and root onto different stuff. The container is just for the convenience of the grower, not the necessity of the plant. Your guide should be your own statement: THEY ARE BLOOMING LIKE CRAZY.

You shouldn't add more dirt. How about getting a larger cache pot to place your container it, that will help prop op the plant?

All of the anthuriums I have planted in the ground, regardless of whether they are species plants like A. veitchii or A. plowmannii or hybrid A. andreanums, have pushed out aeriel roots. A few have truly huge root masses.

It may be impractical for you, but if it were me, I would simply plan on growing a massive plant and keep stepping it up.

Or, if you are into trading, you can separate them and make new plants

bihai,

I actually almost put your name on it when I posted it, I was almost positive it was yours, but I didn't want to misquote you if it wasn't!

Thank you all. This is really helpful to me.