|What would be a good plant to plant around a mailbox all year round?|
|I would vote for planting annuals rather than perennials. This way you could change the look as the seasons change. For instance, try a small vine such as yellow flowered Thunbergia to grow up the post (you would need to provide a bit of mesh for it to cling to) and surround that with one of the new white marigolds (about two feet high) and perhaps some of the Alaska nasturtiums which have a green and white variegated foliage, mixed orange and yellow toned flowers and stay under a foot high around the outer edge.
Portulaca (Rose Moss) is an annual rather than a perennial, but it seeds itself down and comes up each summer. Blooms all summer and takes little care. Another self seeding annual that blooms all summer up until frost is Four'O'Clocks. They come in several colors. I have them in Hot Pink, and Bright Yellow. You can save seeds from the plant easily and just drop them wherever you would like to start them. Drop them during the winter or very early spring. They will grow to about 3 feet high.
If you'd rather plant perennials, how about Stella de'Oro daylilies? They are beautiful plants with bright yellow blooms from early spring to late fall. They are the longest-blooming daylily, and produce prolific blooms. The lighly ruffled, 2-1/2 inch golden blooms curl back to create a bell shape, and mature plants do an outstanding job at choking out weeds around them. The plant, even when not blooming, is very pleasing to look at; easy to care for, minimal maintenance, prolific leaves that are "architectually" pleasing to the eye.