Elevated slope

Hey guys...newbee to the site.
1. Does anyone know how to do an elevated slope. See I have azalea's that were not doing so good in a flat bed so want to elevate bed to get them better drainage so maybe they'll do better. What's a good height to start and end slope? Also by the walkway how would you keep the dirt from eroding? Do you need to make a mini wall, like putting 3 bricks, 2 bricks, then 1 or would it work to slope the sides inward then mulch on top... would that hold it?
2. Does anyone know where I can get a dwarf bottle brush tree?

Hope not to confusing...thanks in advance for your help.

I think you're talking about doing a raised bed for your azaleas. We usually use railroad ties 3 deep and lined with landscaping cloth to help protect the wood. Azaleas are acid lovers, so before you start doing raised beds, you might want to have the soil tested. It may be something as simple as adding amendments to change the soils ph. They like fun sun as well.
You might want to check the seed exchange for the tree you are looking for. There are numerous plp exchanging plant materials, selling plant materials on there.

I'm also curious how you know the problem was them being in a flat bed? As doccat said, they are acid lovers and for some reason I picture TX soil being rather on the alkaline side. If your soil pH was too far off from what they like, that would have been enough to make them unhappy (and even if your soil is normally OK, if they were up by the foundation of the house, the foundation can leach lime into the soil and make the soil more alkaline than it would be ordinarily). Or if you had them in too sunny of a location--in your TX heat I imagine they'll be happier if you give them afternoon shade. Or if they were planted in the late spring or in the summer and didn't have a chance to get established before hot weather hit they could have easily looked ratty all summer, but assuming other conditions are right they should be fine next year. I guess what I'm saying is before you go to all the trouble of creating a raised bed and transplanting them you might want to investigate what the true problem was, otherwise you might go to all this trouble and then end up with the same problem again. Unless your flat bed is really heavy clay or unless it's a low spot that stays wet all the time, I think there's a decent chance your problems were caused by something else.

You don't mention where the bed is but since you mentioned a walkway it makes me think it might be a bed near the foundation of the house...if that's the case, then I would not try to raise the soil level in that bed, you don't want to hold moisture up against your foundation. And as I mentioned earlier, foundation beds aren't necessarily the best place for acid loving plants since the foundation can leach lime into the soil.

As far as your bottle brush tree--here are the places that are listed in Plant Scout as selling any Callistemon species. Some of these aren't going to be dwarf, so I'd click on the plant name first and check out what height it gets, but hopefully one of these will work for you. The one cultivar that I know is nice and dwarf is Callistemon 'Little John', it's not listed in the Plant Scout but you might try asking local nurseries about it, if they don't carry it they can probably order it for you. http://davesgarden.com/products/ps/search.php?search_text=Callistemon

I grow Azaleas and Rhododendrons in my garden, loads of them, in fact these are the more reliable plants that I can guarantee will give huge success so early in the year both on in size and colour, so I think it is the growing conditions you have to correct. these plants need an acidic soil, added to that, at planting time, they also require loads of leaf mould added to the planting hole, they need dapple shade and dont like winter morning sun after a night frost as the buds drop off or rot. they require a moist, but free draining soil /position, you have not said what the problems are that makes you want to move them so can you give some info as to what, like leaf drop, discolor, lack of flowers, wilt etc, all that would help us to identify what the true problems are, if your soil is clay, you will need to alter that, adding some peat, manure, leaf mould etc, if it is not acidic enough, you will find it hard to correct and for raised beds, you will need to buy the right acidic soil to fill the beds, if it is too dry then you need to add lots of stuff to the soil to help it retain enough moisture, plus the leaf mould, these plants come from mountain areas of chins, japan etc and are in dappled shade , you dont see them in full hot sun as they cant tolerate these conditions, so maybe TX is just too hot for them unless you can offer all the other conditions they also need, please get back with further details about the problems that the plants have.
A nice natural looking slope will look great for growing plants, but again, you will go to a lot of expense, work and energy, unless you have shade, the right soil, conditions etc, as will be the same with a properly constructed raised bed area. hope this helps you understand some of the conditions you require. good luck. WeeNel.