One thought you may want to keep in mind is to incorporate more permanent plant types into the bed. While a selection of perennials will certainly return each year, they do disappear in winter, leaving the bed a blank hole for many months. Personally, I consider this a highly undesirable feature in an area that is so conspicuous and open to public view. Incorportaing a few smaller growing shrubs or dwarf evergreens would provide a far more permanent structure (i.e., "bones") that would provide interest during the off-season as well. There are a few hardy perennials that will provide a more evergreen presence also, and an assortment of groundcovers that offer this feature too. Some other ideas to consider: reconfigure the bed to a more naturalistic shape - a rectangular bed plunked down in the middle of an expanse of lawn looks unconnected and awkward. Get rid of the little strip of lawn running between the sidewalk and the planting bed - it serves no purpose and increases the maintenance. And perhaps mound the soil slightly and include a few landscape boulders to offer some context as well as permanence - small shrubs, low spreading perenenials and ornamental grasses look especially good creeping or cascading around these rocks. And don't rely solely on flowers to achieve results. Flowers - even those provided by so-called long blooming perennials - are very temporary. Look for a contrast of plant forms, textures and attractive foliage to provided much more long term interest than just flowers can provide.

The flower saya "Lantana", but the leaves look more like a sedum. Does anyone know a lantana-like plant?

I think you've hit it. I knew it had to be some kind of Verbenaceae. Thanks!

I can't think it was a zephyranthes--I have several and the smallest I have has flowers larger than that. There is a kind of groundcover plant with starry white flowers that sounds more like what you're describing, but I can't remember its name. It's in the lawns that aren't treated with weed killer (like mine) and it's pretty until you try to get rid of it! Slender leaves maybe an inch or inch and a half long, and kind of green buds or seedpods--I've never investigated. I'm not fond of it. When we were first here my husband saw this pretty little plant and dug some up and put it in a flower bed for me, and I agreed with reservations that it was attractive, and then spent the next several years pulling it out. I try not to remember the names of my enemies. 'Course, these days I don't do to well with my friends either!