Park Seed company sells a very tall variety of zinnia (elegans) seeds. Parks Picks. They come in seven different colors.

They're supposed to grow 40-50 inches tall. You can get the seeds germinating within a week and have them ready for the garden in three weeks.

Link to Parks website and check out item #90135.

Just thought of a couple other annual blooms you might try, and they're almost always available at most garden centers.

Cosmos and cleomes.

Both grow rather tall. I've had cosmos here in southern California reach almost seven feet tall. Five and six feet are common. In zone 5 where you live, they should reach four feet in height easily.

Osteospermum or snapdragons.

Marigold, Flagstaff, supposedly the tallest marigold at 4 feet, and Sunflowers which have a lot of range in height, depending on which ones you plant.

yes check out the superb selection of sunflowers these days. They ain't just yellow/orange with brown center anymore :o)

Wow! you guys are great...feel free to mention any others.....I don't use many annuals in my garden so I'm not familiar with the varieties. I appreciate any and all suggestions. I'm going to helps someone put in a narrow border of annuals with the backdrop being a white picket fence. Thanks everyone!!! :-)

Plants from the malva family are nice... hollyhocks, lavatera, etc. Hollyhocks are available everywhere, and lavatera are a snap to start from seed. It's too early in the morning for me to remember the other plants I'm thinking of in that family! But they're all good and I rely on them all over my garden. Oh, malva sylvestris might be the name of one I'm trying to think of... nice lavender flowers with purple veins. For me they bloom up until frost.

I am renting in a condo-type place. We do have a community plot of our own but nothing you could consider permanent. Such as it is I am confined to annuals. Well I ended up with an extra phlox 'david' because I thought I bought a dud, got a second, then this one came up after all. So that is in there too and whenever we move I am taking it with me.

Oh yeah don't forget DAHLIAS!! Big plants, gorgeous colors, and the bloom up until frost. Then you dig, divide, store and plant them again next year. Up in our climate zone they are indeed an annual.

I recently started planting an annual called Pink Flamingo Celosia, which gets about 3-4 ft tall. The flowers are wonderful, and can be easily dried. Also what makes this annual striking is the foliage, it has a deep purple tint to it's leaves. It's nice looking just for that alone, but I also love the flowers. For me it's reseeded and I see little seedlings popping up again this year.

To see a pic....

Here is a link that might be useful: Pink Flamingo Celosia

I really like Mexican Sunflower (Tithonia rotundiflora). Direct sow now and they will grow to at least 5 feet tall and full of flowers!

Here is a link that might be useful: mexican sunflower

There are also some shorter sunflowers that you can try. I can't think of the names right now, but I think they still have some short varieties at Walmart. Good luck!!

Mel