Oenothera filiformis

Long-Flowered Beeblossom. (f.k.a. Gaura longiflora) They're more likely to grow strongly upright (non-floppy) in full sun and medium-dry to dry soils. The bees blissfully work the flowers from early morning until they close by mid- to late morning. 5-8' tall x 4' wide (rather gangly looking after the flowers close each day but great for the pollinators). The plants are short-lived (biennial here). Self sows (sometimes extensively).