Bob, I agree with you about Catharanthus roseus (Vinca). I've always called it a "parking lot plant" meaning that it can thrive in a totally hostile environment. Your picture sure illustrates that perfectly.
, I'm going to add Angelonia serena (a tender perennial used as an annual like the Catharanthus) to the list. It hasn't come back year after year, but it sure does laugh in the face of the harsh conditions it finds in my west facing, full blazing sun, non-irrigated (and rarely watered) front bed. Oh...let's not forget the Alabama red clay soil.

Angelonia blooms it's head off, non stop, until a heavy frost and never needs cutting back or deadheading. It never fades in the sun and heat and is pest and disease free for me. I might add that hummingbirds like it.

rhizo,
Good to know that about Angelonia. Recently I have been tempted to order seeds for Angelonia serena or serenita. My neighbor's Angelonia serena kept blooming all winter and they are into their 2nd year, but we had no deep freeze this winter in our neighborhood (2 miles west is a different story).
The new Gomphrena fireworks (a totally new type of Gomphrena) is proving to be the same. But it grew so large I did not plant it's seeds again this year. The local zoo was very impressed with it's performance.
Bob

Here is a link that might be useful: Gomphrena fireworks

Yes, and I would add the old fashioned tall pentas to the list too. Any plant that blooms all summer in our hot humid southern sun is, by definition, a trooper DELUXE.

I love "annual" vinca! (Catharanthus roseus is most definitely an annual in my zone...). I grow some every year, usually a lavender color and the polka dot one, such as the one you have. That polka dot one was in the first batch of seeds I ever grow many years ago, bought a pack off the seed rack along with a couple other annuals - so I have a special fondness for it. :0)

We recently moved from a Nevada small town. Temperatures ranged from 1-106oF and yearly rainfall was less than four inches.

Russian sage, I don't know which one, once established did well for six years with no irrigation.

Dona, I heartily agree.

Mxk3,
Vinca was my #1 favorite plant. I tested seeds from all over. A kind breeder even gave me his entire line to test. Had many discussions with the company that developed Cora. Bottom-line is it gets hit with Phytophthora Stem Blight & Root Rot here and in many other areas and that's it...sudden death.
I have seen it grow in cracks before so I even tried growing it between bricks. Nothing... come mid summer most are gone. I keep collecting seeds from the survivors hoping it mutated resistance, but no luck. I still love it and grow it anyway.

Albert,
Russian sage is rated for my zone. But I can't grow it in my yard. It never takes off.
I think you hit it. I treat all my plants equally and water almost daily. That does not work well for either russian sage or vincas.

This post was edited by bugbite on Sun, May 19, 13 at 11:58

My russian sage is planted in a part of the yard that can't be reached by a hose and I've never toted water to it!

Vinca is my favorite annual esp since the deer don't touch it. Takes a while to kick in around here as they love the heat but then they are golden. This year tries Titan mix and am very impressed so far. Also did Cora Cascade but no cascading action as of yet.

Russian Sage is beautiful, but it melts out in our humidity here after a few years. In other climates, I have no doubt that it's a dandy.

My husband and I lived in New Orleans during the eighties. That's where our children were born. We rented a home the first few years and each spring I would plant a row of Vinca across the front of the house that had no landscaping whatsoever. (This was when I was a newbie and didn't know about a lovely phenomenon known as reseeding.) A lovely Hispanic woman on our block would walk by and say "Your house looks so happy!" That was the beginning of my love affair with vinca which continues to this day. I planted a Cora called "violet" this year with chartreuse Durantas in my streetwise border. I know there are vincas out there with purple tones. Hope I found it this year. But if not, it's likely to be lovely anyway.

In another bed this year, I planted one that is Burgundy Red with a prominent white eye along with white Serena Angelonia. I can hardly wait for it to fill in. I know I will love it.

I'm going to nominate the lowly pansy. I'd started some plants from seed but late in spring. Anyway, I tossed the seedling's out in favor of some full-sized plants already in bloom. Well, the little stinkers I tossed out, refused to die. I'd tipped the pot over on top of some potting mix and the things rooted themselves. Wow. They are now safely tucked into their own pot.

Vincas are real troopers. I have some white ones like yours that I planted last year, and they are still going strong and reseeding.

The one in this pic is about 3-1/2 years old. No protection from our occasional winter freezes. The pot in front of it is 6", put there for size.

i say that zinnia is the easiest annual ever!!!