Ideas for moisture tolerant shrubs

I'm looking for some ideas of large shrubs (or possibly small trees) to plant on the edge of my yard to provide a bit of privacy between my yard and my neighbor's yard. The problem is that this is an area that catches runoff from my neighbor's lawn sprinklers, and they have VERY erratic watering behavior (water every single day for a month, then water every 3-4 days for a couple months, then water every single day again for a month, then stop watering entirely for a month and a half during the heat of summer...you get the picture!). So I need something that can put up with being wet when they're watering every day, but can do with less watering when they're not. I'm happy to water every 3-5 days if I have to, but given our dry summer climate I don't want something that I'm going to have to water every day if the neighbors aren't watering them for me. My soil has a fair amount of clay, and they'll be planted on a relatively steep hill if that makes a difference.

Besides the moisture tolerance, the other requirements are evergreen and at least 10 ft tall but able to keep it to no more than 20 ft (electrical lines close by on one end of the yard), and can take full sun (our average summer highs are in the high 80's, but we do get occasional heat waves where we hit 100+ for a few days to a week at a time). Ideally, they'd be narrower than they are tall because I don't want them taking up a huge chunk of the yard width-wise. And in a perfect world, they'd also have pretty flowers!

I did some advanced searching in Plant Files and found a couple plants that look promising, so I'd love thoughts on them from anyone who's grown them, as well as any other ideas. Here are the ones I saw:
Viburnum cinnamomifolium
Viburnum cylindricum
Viburnum obovatum
Cyrilla racemiflora

I spend most of my time looking for drought tolerant things that will get by with little to no watering in the summer once they're established, so this is quite new territory for me!

Cyrilla racemiflora "Titi" was the first thing that came to my mind. I dug up a sucker from a wild one last winter and planted it in my woods. They normally grow in wet areas here, but I haven't watered my transplant but maybe two times this whole year and it is growing fine (even with the drought). They're tough plants.

Great--sounds like exactly what I'm looking for! Do they grow reasonably fast, or are they pretty slow growers? And how evergreen are they? PF has them as evergreen, and I saw your comment that they were semi-evergreen, but when I went on Forest Farm's website, they have them listed as deciduous. Do you think it would usually keep its leaves here in 9b? I don't mind if it would drop some in a hard winter, but I'd prefer if it had leaves most of the year.

I sent you a D-mail. I'm in 8b, and some leaves turn red, but most will stay on through the winter. I'm not sure about the growth rate, because mine got eaten back by deer and it's been unusually dry this year. With no deer and ample moisture, they would probably grow quickly.