Azaleas and rhododendrons require adequate water pretty much forever. Unlike some plants,they do not establish deep roots over time to carry them through periods of drought. They are shallow rooted and will need artificial watering any time the natural rainfall is insufficient.

I would not plant them before your trip, especially if your local weather has been dry. Frost and the onset of winter should not be a problem, but checking with a good local nursery, your County Extension Service or a university would be a good idea in order to receive specific information about late summer/early fall planting in your particular planting.

I have a little different approach. I live in hot humid PA. I never water more than once a week, especially in well mulched beds. So I would water, if necessary, heavily just before leaving, and then water, if necessary just after returning.

If the plants are hardy for your area, and were field grown (balled and burlaped), there should be absolutely no problem planting them now.

If they are tender for your area, planting anytime will be a problem.

If they were container grown, and are hardy, then they should receive a little protection this winter, especially evergreen azaleas. Some wind protection and sun protection is good. I use cedar shingles stuck in the ground to provide this protection for very small plants. For larger plants I use burlap for up to 3 winters, no more. If you use burlap, keep the top open. The burlap is there only to protect the plant from sun and wind but you must have good ventilation and access to rain.

In general, fall is the best time to plant. If they have been fertilized after June, then that may be more of a problem than your being away for a week. If they were fertilized after June and have tender new growth coming out, this probably won't harden off and will freeze back. Hence, you may want to at least protect them with burlap.

I live in central NC, where it can be quite hot and humid in the summer. We have had a relatively rainy season though. I am just afraid of them dying because I planted them at the wrong time, especially the expensive encores! I appreciate the suggestions - I am quite new to this whole outdoor planting thing.