When I am choosing colors for flowers in front of the house I like to pull in some of the colors that are on the house. This can really tie in the home and the garden and the eye will travel from the flowers to the front of the home. If the home itself is painted in neutral colors then you can use the color of the front door or shutters for the pop of color. I would put the plants with the colored flowers in a flower bed with some plants that have neutral leaves on them, such as a pale yellow leaf or off white. Sometimes plants with these colors can be hard to find but they are out there.
I would have a great time planting a garden with the colors of this home in the yard. First of all I really love both the design and the colors of this home. So of it would be great to have a garden with a lot of yellow, orange and red flowers (also the different shades of those colors) to make very interesting yard. I would also include some grayish foliage. You could put these flowers around the trees or in pots on the porch. With these wonderful large windows you could put some pots just inside the windows with the same colors.
Here are a few pictures of some plants that could be used.
The first plant is a Pansy Viola, the second one is a Dusty Miller and the third is a Rust Orchid. So with these three colors and/or some variation of them the colors of the home and garden would really tie in and I would also add some bright yellow for some pop. My family had a farm house painted in the traditional farm house colors. So to make the garden more interesting we painted the front door red (I love a red front door) then we were able to add a lot of red to the garden. The shutters on this home were green (that is an easy color to put in a garden) and the house itself was white. That made red the only pop color we had to work with. It was fun but not as much fun as you can have when there are more colors to work with.
Hope you have fun with this.