I am not sure if this is considered advertising. I hope nobody minds my listing companies by name. Here are catalog companies that I use or am considering using.

Breck's: www.brecks.com

Brent and Becky's Bulbs: http://www.brentandbeckysbulbs.com/spring/

Van Dycks: (don't know about reliability)
http://www.vandycks.com/index.phtml

White Flower Farms:
http://www.whiteflowerfarm.com/

Check out Daydream Tulip:
http://www.brentandbeckysbulbs.com/spring/productview/index.php?sku=02-0407
I have mixed feelings about color, but it is supposed to be a good perennial and multiply annually. Breck's also sells it.

Skip the Breck's catalog.....white Flower is good as is Brent and Becky's...I hear. I like Van Bourgundien.
You will have to get an early rush order to get good bulbs in early September....but you surely don't want old mouldy bulbs that won't grow.
Linda C

John Scheepers is a good source, as well. Many types of daffs and tulips available; you could call and explain what you need and have them sent in time.

You might consider giving Fall Crocus bulbs or Colchicums. I understand they will actually bloom without soil, water, or anything (even in the bag they're shipped in)! You could put the dry bulbs into a small glass and tie with ribbon, or, if they're blooming, just lay them at the top of the plate at each placesetting. September would be about the time they would ship, maybe even a bit earlier.
You have a great idea there! I have a feeling that Brent and Becky's would work with you to figure out the best bulb and ship them to you in time. They give highly personalized service. (And they are one of the more reasonably priced companies for the size bulbs they ship.)
Definitely skip Breck's. The ones already mentioned are good. I also like McClure and Zimmerman, though Brent and Becky's usually beats their prices.

I would use Scheepers, because they have a wholesale side---Van Engelen--and you can make large orders & get a price break. *And* they are very good size, high quality bulbs. Also a family business as is Brent & Becky.

New2Gardening---if you get your tulip bulbs in your hands in early August, they will have been dug out of the ground in July in the Netherlands, which is too early! They have to "cure" after digging, then of course be shipped etc. Your wedding favors will be much less likely to come up next year & thrive.

If you want to give some kind of plant as a favor for a summer wedding, how about small potted hydrangea plants? We got ours that way & it is out in the front yard fright now, covered with blue blooms & reminding us of our friends' wedding. They are obtained by cutting, and somewhere in some greenhouse there are thousands of them ready to be shipped to you.

Home Depot and Costco always have their tulips available by the first of September here in California. Al

I wouldn't count on a box store like HD or Costco. Another wonderful place to get bulbs is Colorblends. They only do the fall bulbs. I first heard about them from one of my teachers at horticultural school, then I talked to them at a trade show. Really nice people.
Wherever you get the bulbs from, I would contact the company to make sure you can get the bulbs by the date you want them. Some won't ship until October or even November.
I think bulbs as a wedding favor is a great idea! And easy- you can even buy little netting bags to put them in and a little ribbon and done!

Here is a link that might be useful: Colorblends

Well, sorry about that- skip Colorblends. I just got the catalog the other day and hadn't thumbed through it. They won't ship before Sept 22.

For others, if you like straight forward people, Colorblends is for you. They have an entire page in their catalog on why bulbs shouldn't be harvested and shipped early. Unfortunately that page isn't on their website but I urge everyone to get a catalog and read it. A good explanation of why daffodil bulbs aren't good in box stores, and why you often find fungus or mold on them.

You should be able to find some cheap wedding favors online. I'm not sure about bulbs, but there are good deals on some other things. Here is a link I've found to be helpful.

Here is a link that might be useful: Wedding Party Favors

Just got my bulbs today from www.tulipworld.com and they all look pretty good. ofionnachta: I called them to ask about what you said and they said these were harvested at the same time that everyone else's is done and there is no reason to worry- I called brecks and they told me the same thing.

So now the hard part, to start putting on 300 tulips in nice little favor packages!