I do believe this is Spiraea cantoniensis. The one most seen would be the cultivar Reeve's double. My bridal wreath does not bloom until well after leaves have opened, and it surprised me to see that some do. Makes a very dramatic statement.

I have a whole list of yellow flowers for you, but I've forgotten when many of them bloom. I'm sure most of them will love your sandy soil. They should all be hardy in zone 6. Some of these are specific plant species, while others are specific cultivars. They all bloom yellow though and I plan to acquire them sometime in the future if I don't already have them! -Verbascum nigrum -Gentiana lutea -Lysimachia punctata -Solidago (goldenrod; most species and cultivars yellow) -Berlandiera lyrata (smells like chocolate!) -Echinacea paradoxa (there are also many cultivars, like 'sombrero yellow' for instance) -Aurinia saxatilis -Achillea (yarrow; most species and cultivars) -Coreopsis (most species and cultivars) -Kirengeshoma palmata (needs lots of shade) -Hollyhock "Chater's Double yellow" (technically a biennial but reseeds like a perennial) -Helianthus multiflorus 'Flore pleno' -Heliopsis helianthoides -Frittilaria imperialis 'Lutea' (also available in orange) -Ligularia (most species and cultivars; needs lots of shade) -Penstemon pinnifolius 'Mersea Yellow' -Thalictrum Flavum 'Glaucum' -Daylily 'Stella D'Oro' (I'm sure there are other yellow cultivars but can't think of them at the moment) I'm sure there are many more that I'm forgetting but this is what I can think of at the moment. I actually didn't mind researching this for you. I was meaning to compile a list of yellow perennials for myself anyways. Hope this helped you out. P.S.-How is your aglaia odorata doing (you grow this, correct?)?? I got one last year but it has unfortunately died (left it outside for ONE night below freezing by mistake, and that was all it took...).

For a large quantity of blooms to cut, you will probably be better off with annuals than with perennials, especially if you're growing them from seed. I grow mostly perennials and woody plants, but do have a few thoughts for you. Zinnias will grow and bloom quickly, but I find the water turns very smelly after just one day; so if you're going to arrange them the day before the wedding, that's a consideration. Cosmos also grow quickly, make good cut flowers, and should give you masses of blooms in colors ranging from white through pinks to deep red. Snapdragon is another quick grower, blooming in late spring to early summer. I hope someone will chime in with more suggestions for you. If not, perhaps try the Cottage Garden forum - there are lots of very friendly and experienced gardeners there from all over the country ... there's bound to be someone who grows annuals in your climate. Don't forget fillers (like baby's breath, gypsophila) and greens - you can choose from solid or variegated leaves, smooth or rough textures, large & bold leaves or long and narrow, even trailers like ivy, whichever best suits your arrangements and your fancy. A trusted friend to help with the arrangements sounds like a good idea. Have a wonderful time with the preparations and best wishes on your wedding day.

The following is based on growing in New Hampshire (Zone 5)but if you live in a higher zone there may be more options for early-blooming cut-flowers. Dorinicum or Leopard's Bane is one of the first perennials to bloom in the spring. It produces tall, good-sized bright yellow daisy-like flowers and makes a great cut-flower. It's very reliable and comes back for me every year in NH. Larkspur would be another good early bloomer as it does best in cool weather. As for Zinnias . . . it may be THE BEST cut-flower for size, color, and production. Yes, everyone grows it. Look for the unusual types. Baker Creek Seeds has some great varieties most other seed companies don't. Try to grow specific colors rather than mixes. Snapdragons start blooming relatively early and continue throughout the season. It's my 2nd favorite cut-flower. Most other annuals will start blooming later than June, but once started they continue till frost. Iris start early, are reliable and produce great flowers, so that may be a source for cuts. Delphiniums start blooming here by mid-late June so that may be a good source. Some of the Primroses make good cuts. A number of Dianthus bloom early for smaller, but fragrant cut flowers..