If you're painting your front door wythe blue I'd sprinkle some flowers the same color near the walk up. Also, I don't think you can ever go wrong with pine trees. Maybe a star pine?

Hydrangea might do well. for the purple/blue flowers, the soil must be acidic. they also come in pink and white (your last pic). The agapanthus are nice, but just know they aren't always in bloom like that. maybe some Iceberg rose bushes. tons of white flowers.