Petunias and Marigolds can get going pretty quickly. It's hard to make recommendations without some idea of your goals re color, height, etc, if any. Allysum is a good filler or hi light. Annual asters, Cape Daisies. Hope others pop in with more suggestions.

What elevation and soil/light do you have in Colorado? Day vs night temps? Last summer(Z4 NH...wet summers,cool nights), I grew a wonderful marigold called 'alumia vanilla',a white alyssum and snapdragons from the aroma series. Depends on your color ideas. Calendula and purple batchelor buttons offer more height.

whether or not a plug would bloom in july ... really has little to do with whether you can grow the seed to plug size by planting time.. and get them to bloom on time ...

do you have any experience with seeds??? .. do you have an indoor light stand???

and when is your last frost freeze date .. timing out seedlings.. so they arent all tall and gangly by said date is the key ...

whatever you do ... dont rely simply on this ... have a backup plan ... or three ....

try the search engine for this topic ...

ken

here is a start:

http://www.gardenweb.com/gardenweb/query/planting-a-garden-for-wedding

We are zone 5. I have a small amount of experience with vegetable seeds but not much with flowers. I have a nice sized sun room that I have done seeds in and I can get a heat mat. This is a photo of the yard the wedding will take place in. I was thinking of a few raised beds for flowers. The right side of the yard is full sun. July can be very hot here. The nurseries here say the last frost date is May 15 but old time gardeners have told me not to plant outside till after may 31. There is not much color in their yard itself but a nice lawn. My nieces colors are plum white and green but I am sure she would be happy with any flowers in the yard. Thanks for all the ideas

Beautiful setting! My last frost date is the same as yours,but I have remay covers that are sometimes needed until June. Annuals need a fair amount of water. Can you set a drip irrigation line? Can you buy starts from a nursery,like purple or plum colored petunias,verbenas,a deep blue salvia farinacea?...pale yellow marigolds called "Vanilla" with white alyssum "carpet of snow". A lot of California poppies will bloom scattered from seed by mid July. Seeded Nasturtiums should be blooming by then. I grow "Double delight cream"...pale yellow. Lots of luck...your setting really seems to need just pots of color from the nursery...some placed in front of the shed to the left in the photo. Best wishes from NH!

where in z5.. its half the US ...

so you not only want to grow the seeds .... you have to build the beds first ... crikey ...

at least you arent the bride ... lol ... they are usually the ones that are biting off too much ...

ken

http://www.deborahsilver.com/blog/tag/nicotiana-mutabilis/

http://farhansgarden.blog.com/2015/04/19/beat-that-nasturtiums/

The links above are what plants I would use as the foundation. The nicotiana mutabilis, (be sure to get that one! There are three types) has huge impact because of the size. The size in contrast to Airy and delicate flowers.

The nasturtiums are great flowers but I think the foliage is really beautiful. I would envision you growing the nasturtiums up some support and also along the ground to choke out weeds and spill down the sides of your beds. The buttery yellow color would particularly compliment plum without commanding too much attention.

Beyond that I would just go to the garden center maybe 2 weeks before and add the perfect pops to go with your foundation of nicotiana and nasturium. There are some nice deep purple nicotiana varieties. I'm sure something will catch your eye and by July most everything is on sale

I think of July as high summer but looking through my garden pictures, high summer favorites like dahlias and zinnias aren't in full swing until August in my zone 5b\6a garden. July is kind of tough because it hasn't been hot long enough for zinnias and dahlias but it might be too hot for my favorite early summer sweet peas and poppies.

Good luck¡!!!!

I'm in z5 in the northeast with a last frost date of June 1 -- so basically two weeks behind your season -- and I start all my plants from seed. I'm also a long-time seed saver. Are your direct-sown zinnias and cosmos *usually* blooming by mid-July? if so, I'd start some early and direct-sow some and you should come out alright either way.

I love impatiens for giving lots of blooms and color in shady spots! I usually start my impatiens at the beginning of March... I sow the seeds in a 4x8 peat flat, then prick out 6 dozen (or more) seedlings for myself and give away the rest. With that timing, they're starting to bloom at the end of May or beginning of June, which is perfect for me.

Other annuals I typically grow quick/easy from seed are asters, zinnias, marigolds, cosmos, nasturtiums, scarlet runner bean vine, hyacinth bean vine, nigella (love-in-a-mist), centaurea (bachelor buttons), etc. I direct-sow the asters, cosmos, nigella, and centaurea, but often give the others a 3-4 week lead by starting inside. I also always grow things like dahlias, gladiolas, and pelargonium (annual 'geranium')... the latter from cuttings of overwintered plants.

If it were my gardens and my niece's wedding, I'd proceed by sowing some indoors, direct-sowing some outdoors, and have a backup plan of filling in with other purchased annuals as needed.

Kathy, if you're specifically looking for annuals that would match the color scheme of plum, white, and green, I'd definitely be checking the available varieties/colors in asters, nicotiana, sweet alyssum, lobelia, cosmos, zinnia, stock, dahlias (tubers), centaurea (bach. buttons), perhaps mallows? hyacinth bean vines would be nice on trellises! Those come to mind, anyway. :)

*ETA: don't forget neat foliage plants like coleus!

* other possibilities: ageratum, larkspur, garden balsam (Impatiens balsamina), perilla

As someone who did what you are trying to do, here are my suggestions. Plant containers. Scavenge planters, urns, hanging baskets, whatever goes with the setting and style. Use cuttings of geraniums and trailing ivy in addition to your seeds. With containers, you can position them for best effect on the day, tweak them with additions if necessary up to the last minute, and give them away along with arrangements. Which makes me also ask what the plan is for those, if any? I think you'd want to coordinate.. My two cents!

I have no idea what the plan is for the arrangements yet. I really do appreciate all the ideas everyone here has given me. I have been out looking for planters but I do like the idea of some hanging baskets as well. Thanks!!