Landscaping, need tree advise

I am helping my daughter and son in law design and landscape their new yard. Nothing has been done. I need to find some trees. The front yard needs a shade tree, I was thinking of the Royal Empress or the Tulip Poplar. I don't know much about these, but I really like the pictures of them. I would like to put a clump/grove of Quaking Aspen on the north side of the driveway, which is very sloped, where there would be no grass, just trees, plants, walkways of stone and decorative benches. I also love the flowering Dogwoods and Crape Myrtles. The Weeping White Birch is very pretty, my son in law likes the white barked trees.. I have been looking at tree sites but need advise. Small slow growing evergreens and small flowering shrubs will be sporadic throughout the landscape. (Any suggestions?) I have Hardy Hibiscus and Roses and many perennials.
Any suggestions would be appreciated as to your favorite trees, flowering and fast growing, not very messy and non reseeding would be a plus. (I am not asking much am I?) I will try to get there Friday with my camera to take some pictures so you can see what I am up against.
Thanks for any help, Marie

Do they live near you? If not, we'll need a little info on what their climate is like. The Royal Empress tree is invasive in many areas of the country, I don't think it's as much of a problem in the west, but if they live anywhere east of the Mississippi I would absolutely not plant it. For the aspen, how large is their yard? Aspens are not a plant for a small suburban lot, but if they've got some acreage then they'd be nice. Crape myrtles would not be hardy in your zone, but if they're in zone 6b or warmer then those would be nice choices.

Assuming they also live in Utah, here are some sites with plants that are either native to the area or appropriate for your climate, hopefully this can give you some inspiration.
http://www.greatbasinnatives.com/servlet/StoreFront
http://www.wildlandnursery.com/

They live 5 miles away from me, on a slope near the mountain. They have 1/2 acre of land. The area the quaking aspen would be in is around 35' x 20'. I have quakies in my yard amongst a maple and 3 pines - and love them. I plan on checking the nurseries around here for some ideas. Pictures of her yard are coming tomorrow.

OK, as I promised, here are some pictures, now you can see what we are up against. Any help is appreciated.

That is the front yard. The front is 39' and 48' back to the house. This is the front side yard that I want to put quakies in

Now, this is the bottom of their property, very sloped. The yellow is mustard weed, gotta get rid of that stuff. Also, they have a great crop of alfalfa. A lot of work ahead.
Any ideas?

They are thinking of planting small trees in the parking strip all along the house. ???suggestions???

Don't do any planting in the parking strip, or tree lawn as it is sometime called, without first consulting with the local street department, homeowners' association (if applicable) or local zoning agency. Planting in tree lawns, which are public property, is highly regulated for safety reasons. There are two reasons for regulation. One is vehicular safety. No tree/shrubbery should be planted that could eventually impede a driver's vision, such as blocking the view of a stop sign. There shouldn't be anything planted too close to a fire hydrant either for obivous reasons. The second is buried underground or over head utilities. You don't know what's under there. If you hit something when you dig you could have a big problem. If you don't actually hit something, there could be something close by that would impede the root development of the tree. The size of the tree is also governed by any overhead utiltiy lines. If you have any overhead utiltiy lines then the largest permissable tree is usually one in which tree's mature height is less than 20'. So my advice about right-of-way planting is "don't".

Or if you don't like the look of the bare strip of grass, you might be able to plant a bed of nice tough perennials to add a little interest, again you'll have to be careful when you dig but at least you won't run into some of the other issues. I agree about calling the city first to see what you're allowed to do.

The area where you said you're going to plant the aspens looks a bit small to me. To be fair, I've never grown them, but I know they spread and form a grove and that just doesn't look like a big enough area to me. It might work for a while, but in the long term I think they (or whoever they sell the house to a few years down the road) are going to have a big headache.

I'd also be careful with where you put any trees--since there are nice views there, I'm not sure what from what angles all the neighbors are getting that view, but it's not very neighborly (and in some areas possibly against the rules) to plant things that are going to block the neighbor's views of the hills. It's hard to tell from the pictures where would be blocking a view and where wouldn't, but I'd definitely think about that before you plant anything big.

The biggest initial challenge is going to be getting rid of those weeds. I'd start by cutting/mowing them down, then till the area and consider putting down some black plastic for a while to solarize the soil and get rid of any weed seeds. That approach will probably result in less weed problems down the road, but it would also mean they probably couldn't plant much this year because by the time you're done solarizing the weeds, it's going to be too hot to plant things. Or if they want to plant sooner, I'd still cut down the weeds, but instead of black plastic use newspaper instead, it will decompose eventually and you can cut right through it to plant things. I'd also give the area a liberal covering of pre-emergent herbicide like corn gluten before you put the newspapers down, that should help cut down on weed seed germination from the disturbed soil.

Since their house is in an area that seems like it borders pretty closely on nature, personally I'd try to go with native plants as much as possible, those will blend in better with their surroundings (not to mention they'll be lower water & lower maintenance). The sites I linked to above will give you some ideas. And you can also try the High Country Gardens website, some of their plants won't be hardy in your zone but some will be. And although their plants aren't Utah natives, most of them are native to somewhere in the west so their water needs will be compatible.

Arbor day foundation also doesn't recommend planting a tree in that strip. Usually not enough room for the roots. Ground cover in the strp would work great.
http://www.arborday.org/
Their web site gives great advice.
The tulip tree gets huge up to 80'. I'd do a smaller tree in the front probably 20'.
That sloped section would look great with a retaining wall.

Be sure to check the GardenWatchDog before you order from High Country Gardens. Their reviews form DGr's this spring have been slightly mixed.

http://davesgarden.com/products/gwd/c/28/

I've ordered from them tons of times and never had a problem. But I was really suggesting them more as a source of plant ideas since their website is a good reference, I should have been more clear about that and mentioned that you can likely find some of the plants cheaper locally (regardless of Watchdog ratings). I did go and look at the couple of recent negatives and I'm still not too worried about them--a few of the people sounds like they never even contacted HCG to let them make things right so I don't put too much stock in those. Even good companies are going to have things happen to the plants in transit from time to time so to me it's all about how they make things right, and if someone never contacts them to make things right then to me that doesn't count as a "real" negative. And there weren't enough recent "real" negatives compared to the number of recent positives to make me think that things there have changed significantly in recent months. So speaking for myself, I still wouldn't hesitate to order from them.

I would love to go to town on that yard but your so different climate wise I'm not sure where to begin. Unless water is dirt cheap there you will have to go with drought tolerant everything. Use lots of natives. Looking at that wild hill in the back ground it doesn't look like there are a whole lot of native plants to choose from.

As far as the tree strip I would check with a whoever is in charge. City, town, HOA. If it is allowed you can just call the power or phone company, they usually will come right out and spray lines so you don't dig up their stuff. There are many trees you can plant in that little strip. We have live oaks growing in those little strips in Savannah so it can be done. Live oak not a good choice for keeping the sidewalk in one piece BTW. Makes for a very good looking street when it's 200-300 years old.

WOW, 200 - 300 years old.
The city that I live in and just down the road where they live have trees growing in the parking strips. They have called "blue stakes" to see where the power, gas and water lines are. So many ideas.
This is great advise. I have been doing a lot of research. Can't wait to show the progress. Money for them is a problem at this time so it may take a few years, but we will get a good start on it. I believe this thread may go on for years.
Thanks all for the advise,
Marie