I was going to direct you to the Amaryllis forum, but I see that you've already found it :).

This is so much easier in person but I will try to describe my experience with amaryllis roots. When you get the bulb you have two basic "root conditions". Brown flat and dead. (imo) Slightly white, slightly thick and round and slightly alive. (imo) The brown flat dried up and 'dead' ones I now actually rip off the base of the bulb carefully. If done right (you must grasp individually at the base) its a cleaner break in my opinion. I leave the white-ish intact ones alone. These can take up some water, but I can't say I know that they continue to grow when given a chance-- I have assumed not because I've assumed that once the root is dormant and done growing that it won't start up again. I could be totally wrong on this but its what I have assumed. The problem with doing this via the net is that ...some bulbs you might buy have only dead roots. Some have a mix. Some have some great long clusters of potentially strong white roots (I always favor these and consider the bulb healthier for it.) So I can't see what you might have or buy. Many bulbs are sold with virtually no roots or all short dead brownish flat dead roots. Try and avoid those. I think they take longer to get started growing (not necessarily blooming though.) So when you force paperwhites in water-- before you know it, you have these attractive white roots going everywhere and coming out from the bulbs! With amaryllis... not really. I think it varies slightly with how much warmth the bulb gets but generally the roots take a lot longer to form and their speed is individual to the health of the bulb you got. So don't expect a 'show' with the roots like you would with paperwhites. Its especially important to thoroughly anchor the bulb wherever you put it so the bloom doesn't topple it in case the roots don't form enough or aren't long enough to support the flowering stalk on store purchased bulbs. If you have a potted bulb it has likely filled the pot with long fabulous white roots (VERY VERY long) from growing all last year(s). They easily hold themselves up. But not a new storebought bulb. So in summary: My personal belief is any thicker rounder whitish roots on purchased amaryllis bulbs will absorb water and are somewhat alive. I assume and personally believe they don't get longer though and new roots are sent out from the bulb for its new life at your house. These new roots are very slow growing. So slow that in many and I personally believe most cases-- won't start or get very long until after the bulb has flowered. Many bulbs flower and definitely have not started new root growth. (especially true if kept in a cooler windowsill or cooler home.) I give my bulbs bottom heat and I feel they do much better and the roots start growing faster. Amaryllis bulbs can be forced in water successfully. I personally don't believe in rooting any plant in water and then transferring it to soil because the roots have likely adapted to an unnatural life in water and have some significant stress changing over (if its even possible) to life in soil. I think with care it can certainly and has been done, its just not second nature. I'm typing this half asleep, I hope this helped a little if it made any sense at all. :) Have you found the Clemson article on amaryllis yet? Its one of the better pieces of information out there. Google "Understanding and Producing Amaryllis". There is a lot of misinformation out there. Hans here is fabulous and really knows what he is talking about (his point recently about cutting the leaves off was excellent and I couldn't agree more in my experience and THIS from someone who had read consistently to allow the leaves to die down all the way from pros and was a firm follower of that advice. This might be fine with naturalized daffodils and such but I don't think it works with potted amaryllis you specifically wish to force from my experience. [I enjoy forcing my plants because I enjoy their blooms in Jan/Feb. They otherwise grow in my climate fine and would do great on their own blooming in the summer.] I think Hans is right and the leaves start compromising the bulb after its been dormant past 'dry out the pot' stage. (Ie: more than a couple weeks.) Its an excellent and subtle point for people who like to reforce their bulbs year after year. There are also some excellent and very experienced growers of Amaryllis here and that's what makes this website just fabulous.

Do you have any links to the look you're going for? I don't like when some of the blooms and foliage are over and some are yet to come, I prefer when it's all open at the same time... I guess what I'm saying is it's hard to put together a pot that puts on a big nice show and sometimes the pictures you see in catalogs and packaging are staged or photoshopped. I usually pack in all one kind and keep it simple. I've seen pots with annual rye seeded on top or clover and the lush foliage sets off the blooms too and always looks good.

Check out the Hippeastrum/Amaryllis Forum on this site. You'll find lots of info there. If your bulb hasn't rotted, it should be o.k. Cut off dead roots and keep the healthy white roots. The bulb should be planted in a coarse soil mix with very good drainage and make sure at least 1/2 of the bulb is above the soil. Water sparingly at first. Places sell the kits with a vase and stones to grow amaryllis is water, but it is not a very good way to grow amaryllis.