Here's the situation....

Can you tell us what has failed? If the bed ever gets watered? If you want height or just some perennials? Vines to cover the wall? Color schemes? Foliage over flowers? Succulents?

Bleeding heart, foxglove, both survive but definitely not their ideal envirinment, so succulents not a good candidate. I water by hand every two days or so according to soil need. Yes, want height hence Japanese Maple in the shade which you likely can't see but please no invasive vines. Not picky about colors --purple, red, yellow.

You could fill the area between the maple and the fern with a couple of daylilies. You would need evergreen type for year round foliage.

That spot has not only heat from the sun but also from the pavement and wall. I'm not sure if Loropetalum would be happy but it would look great with the maple and fern year round.

If you're willing to use annuals, Gaillardia loves the sun and are at the nurseries now.

If you want a simple, elegant look move everything but the asparagus fern and fill the rest of the bed with more of the same asparagus fern. Often just planting multiples of the same plant provides a bigger statement than a mix of several different plants. Eventually the maple will need a bigger place anyway.