I have a hunch that your problem with the Albertas is your climate. These spruces are native to Alberta, Canada where it is cool/cold and moist. Here in central Virginia the climate is like yours...hot and mostly dry. I have found that Hick's Yew, a variety of Taxus media, to be a satisfactory substitute as long as it is wind-protected and assured of adequate drainage. Your local nusery can probably suggest several very good substitutes.
Good Luck!!!

I agree with "taxonomist" about the climate factor - I'm only surprised they lasted 7 years. Every nursery here in my zone 7b/8a climate sells them, and they're doomed to a slow, miserable death from our heat & humidity.