Is there a reliable website that will help me narrow the choice of perennials based on height (12"-18"), exposure (full-to part shade), color (yellow + Red), flowering (late Spring thru Mid-summer or later), etc.? The nursery sites that offer this search will sell you anything!

I have about 100+' of border that winds its way under junipers, boxwoods and bayberries (hence the height restriction), and then into full sun. I love sedum and will be planting some of those along the way.