If those are delphiniums, stuff them in and stake them well. Summer bouquets featuring the tall blue spikes will be special. Frilly pastel blooms are valued for their exceptionally long vase life. Plants are very prolific and bloom from mid summer till frost. Stake China asters carefully to promote strong straight stems.
Single colors are back in vogue.
Mix just the colors you want for cutting. Try the tall elegant 'Rocket' snaps for luxurious spikes of rich color. Provide firm support early, or the heavy flower stalks will sag. From the willowy 'Italian White', with its contrasting black center, to the whimsical doubles like 'Teddy Bear', sunflowers represent the essence of summer in sunny bouquets. Tall varieties need no-nonsense support.