When we first bought our home there was no yard to speak of. We had to tear everything out and start from scratch, at the time I was sad that there wasn't one redeemable flower or bush to keep. Now I'm happy that I could plant every single thing in our yard and make it exactly the way I wanted.
I try to have something blooming at all times in our yard. I used to plant a lot of annuals, but it's a lot of work not to mention the expense to do year after year. The other thing with annuals (plants you have to plant every year) you can only get blooms so big. We have a few in the front, but our yard mostly comprises of perennials (these come back each year i.e roses, peonies, hydrangeas).
One thing I had to learn the hard way is the importance of soil. You have to have rich, soft soil before you plant anything. I know it's not the fun part, but it's more important to put a $2 plant in a $20 hole. I think most people make the mistake of just throwing some mulch on top of something they recently planted and calling it good. I turn over /amend our soil every year, YES the entire yard. The only way you're going to get a lush full garden is maintaining the soil. It should be so soft you could push a pencil right into the dirt.
My favorite roses are anything from the David Austin variety. Especially repeat bloomers. We have Iceberg Floribunda Roses planted along the entire length of our backyard. Beautiful clusters of medium-sized, lightly double, white flowers, bloom all summer and sometimes into October. Once the blooms are dead its important to dead head your roses, just take a clean pair of garden shears and cut the dead bloom/bud off. This will promote new growth.
Another fun rose is the David Austin Camaieux Rose. It reminds me of the roses from Alice in Wonderland. This is also a repeat bloomer, but doesn't bloom quite as often as the Iceberg.
In terms of fertilizing you can use Miracle Gro on roses, and I fertilize my entire yard once a week. However, I have found that Osmocote sprinkled at the base of roses has performed best. This doesn't have to be sprinkled weekly, maybe every 3-4 weeks. Lastly, roses need quite a bit of sun at least 6 hours a day so keep that in mind when choosing a location to plant.