Question
I live in North Las Vegas, NV.  I bought two rose bushes to plant in my front yard.  The yard is desert landscaped. That is the soil is covered with small rocks and there are other drought tolerant plants spaced about two to three feet apart from each other.  The soil is also rocky underneath.  Taking advise from a local nursery, I bought a bag of planting mix and a small bag of bone meal.  I dug a holed wider than the root ball of each bush and mixed the dugged out soil with the planting mix and mixed in about 1 to 2 tablespoons of the bone meal.  I removed as many of the rock from the original soil as I possibly could and planted each bush in the ground, tamping the mix as I went.  Here's the problem and my question.  I was watering the area everyday, 1 hour in the morning from 6:00am to 7:00am and 1 hour in the evening 7:00pm to 8:00pm and all the plants seem to be doing well. I went back to the nursery to exchange another plant that didn't do so well and I talked about how I was watering the plants.  I was told I was watering them too much.  So I cut back to 3 days a week and only 1 hour in the morning, 6:00am to 7:00am.  Almost overnight the roses started dying.  I just don't understand.  Considering my location and weather, how can I get my rosebushes and the other plants to grow beautifully in this desert landscape.  Some of the other so-called drought tolerant plants in my front lawn aren't doing so well either.  This is fairly new subdivision and even the newly planted trees which still have stakes around them doesn't seem to be doing well either.

Answer
It is always difficult to grow a plant where it prefers another type of climate. Roses will do okay in high heat but the secret is to choose only those that like those particular conditions. Roses have genetic backgrounds like humans and some hate the heat and others do much better in it. To try and grow a rose tht like cool conditions just won't work. In your situation you have to think of growing roses as if they are in containers. The containers need to be filled with anything that will hold the water and stop it from getting dried out in the high heat. Although planting mix is okay you do need a different type of material to fill the holes as the planting mix is too much work in regards to watering. Here are a couple of examples on what you can do. Dig up a thick sod of grass and place i in the bottom of the hole. This will give the plant nitrogen when the grass finally breaks down. Keep all your garden waste and place that in a hole as it too works very well. I garden in sandy soil and have used a clump of grass to stop the water from quickly draining away. If you have the space you can make some quick compost. Again any garden waste can be used. Make a one foot pile of waste, then one foot of soil, scatter fertilizer that is high in nitrogen over it then wet it down well, finally cover it with a tarp and try to keep it damp. Use this when ever you have to plant  tree shrub or rose.  It doesn't have to be broken down all that well. Just as long as the material is dead works just as well.
When you buy any shrub or plant, don't buy th 4 inch pots as they dry out too fast and die. Try and get the one gallon pots as this will have soil in them and will last for you. When you plant a tree always put a mulch around the base of anything yu can get in your area. Mulch is your best friend as it will cool the roots and keep the plants moist.
Don't water every day but just do it three times a week. Make sure it gets right down to the roots and do it in the evening. Try not to get the water on any part of your plants if you are watering during the heat of the day as this will definately cause burn spots. Some gardeners will stick a 3 inch plastic pipping along side of their trees to make sure the water gets right down deep.  It is not unusual for roses to make smaller flowers in very high heat. It also not unusual that they want to shut down when it gets hot. The only way you can stop them doing this is by giving them some shade. Here is a list of some rosess that prefer hot weather.
Hybrid teas
St. Patrick
Marilyn Monroe
Dolly Parton
Lady Di
Belindas Dream
Crimson Bouquet
Julias Childs
Hot Cocoa
Gemini
Elle
Our Lady of Guadalupe
Day Breaker
Honey Bouquet
Bewitched
Any roses in the Noisette classification like heat.
I have heard that some of the David Austin roses so well too such as Molineux
Fair Bianca, Graham Thomas, Christopher Marlowe, Golden Celebration
Be carrfull how you fertilize as too much will make soft canes which the high heat will burn much easier. Fertilize in the early spring with any rose fertilizer and then in July with an organic one such as fish fertilizer as this releases very slowly so it won't burn.
Don't give up hope when plants get in a snit and look bad. They will take a longer time to settle in. Planting them when the weather will stay cooler rather than the summer, is also a good idea. Hope this helps a little.