I planted cosmos sonata mix a month ago and don't yet have blooms. The plants are 4-7 inches tall but no buds yet. I'm not sure if the season/climate will affect the seeds but even if it doesn't have any impact, you probably won't get any blooms until mid to late August. Maybe you would want to wait until next year to get a longer season out of your seeds. Just a thought.

I'm just getting going on some more perennial seeds now. They usually have plenty of time to sprout and get big enough (not huge mind you) to get planted out in the early fall. I try to plant out by the first week of Sept so they have a few weeks to get aclimated to their new home before the frosts roll in.
Of course, I am a whole zone cooler than you also, so you may have even more time.

As for the annuals, I know for me they wouldn't have enough time to put on much of a show.

Thanks! I think I'll save til next year...many seeds are annuals!

It depends on what annuals. Some are faster like marigolds, zinnias, nasturtiums.... those you can still start this year.

Ferry-Morse sites give approximate days to bloom to many of the annuals. I found that actual days might be a little longer as the days listed might be for optimum condition, but you can still use them as a guide.

Here is a link that might be useful: Ferry Morse

In past years, I have had cosmos bloom, and drop seed and the seed germinate and those new plants bloom long before frost. When the first cosmos plants where looking bad, I just pulled them out and let the newer ones take over blooming.

I decided to plant cosmos...everything else must wait! :)

Nope.

It's not too late to plant this year.

In Massachusetts we recieved June frosts this year and a 7.5" of rain. I didn't plant my garden until the first week of July.

I already have 3 speckled roman tomatoes fully ripened and picked and a 2 pantano tomatoes that will be ready this coming week.

The trick I used was keeping everything in pots until the weather stabilized --- Which I might add didn't help.

My garden weathered the hail storm yesterday, but my neighbor's garden was torn to shreds.

I'm going out on a limb here, since I live on the other side of the puddle, but over the past few years I have found that one has to rely on instinct more than the instructions given on the packet as to when to plant out.

'Seasons', as such don't seem to exist anymore... we've had November days that were up into the 70's, and yet have had to turn on the heating in the house in late May.

Summer flooding has become a real problem in parts of the UK, and last February we had snow in this area for the first time since 2003.

Growing has become a lottery unless you are using a glasshouse, and every year brings the question of "what might actually produce a crop?". My pear tree hasn't fruited well in this millenium, last year we had a meagre plum crop ( nothing the year before )... runner beans did well, but tomatoes were a waste of time!

I'm glad I'm starting to lose my hair otherwise I'd be tearing it out! :-)