I have interred information in the Database on some perennials , those I grow and have experience with , but I have discovered the hardiness to not always be accurate.
Is there a source more accurate, than some, to rely on.I would like to make the information I input more complete.

I can't help in a positive way, but here's a thought.

Isn't the hardiness of a cultivar difficult to express as a Hardiness Zone?
One unusually cold winter, and plants that are "hardy in your zone" will die in droves.

Also, the USDA Hardiness Zone doesn't capture problems like long springs that oscillate between thaws and frosts, or a late, mild fall that suddenly crashes right down to an average winter minimum.

I usually think of any quoted "hardiness range" as only a fuzzy guide - like Plus or Minus two or even three zones.

Some years, plants will survive far outside their "safe zone" and will even survive an unusally cold winter, if the cold developes gradually and steadily, and there is lots of snow cover.

Other years, "allegedly safe zones" will kill plants supposedly hardy 2-3 zones colder than your average.

I'm always reading comments like "they SAY this is only hardy to Zone 6, but I've had it come back for me in Zone 4 for many years".

But what do I know? I live in Zone 8!

I think Rick's right. It's probably best to consult several sources of information, and go with the average.

Too many factors determine ultimate survival- type of soil (clay, silt, sandy?), actual extremes of temp during any season in a particular year (an extremely cold winter in New England?, an extremely hot summer in Fl?, a prolonged drought in the southwest, etc).

I think of hardiness zones as a guestimate, and assume that my mileage may vary.

Karen

You will find that many plants just flat out have not been tried in colder areas. The best thing to do is consult an older, local gardener and ask away.

I'm in Zone 3A and am growing many things that the literature says are only hardy to Zone 5. Micro-climates are a consideration, too.

with all of the above.
As gardeners we need to experiment to find out what works.

For example:
I have fancy Glads that are listed as hardy to only Zone 8 yet they come back for me every year in my Zone 5a garden. (I got tired of digging them up every year and left them in the ground, surprised the daylights outa me when they came back the following year, and every year since then)

Another one is my Vitex agnus-castus, which is listed as Zone 7...again growing nicely for me in Zone 5a.

with all above + gardeners habits....site, soil, fertilizer, water, sun/shade, not to mention unusual weather conditions, critters digging, and dogs doing their business... I have spaced and planted three perennials in the same area only to have one thrive. Whew we just might be miracle workers

I wonder how fast and how far natural selection can change perennials' or reseeding annuals' cold-hardiness?

I would expect (especially for re-seeders) more of the hardier individuals to survive and drop seed. In subsequent years, recombination and selection among the surviviors ought to tend to produce even greater hardiness.

I would expect the perennials to be selected mainly by disapearing in adverse years, but, if they also drop seed, some hardier individuals might come back (or you can re-establish them from your saved seeds).

My guess is that this kind of selective drift can only change a species' hardiness by a few zones, or make it a little more resistant to surprise late frosts or an early thaw followed by frosts. Does someone know more about this? How much does hardiness vary within a species or within a cultivar?

It's another reason to save your own seed. Your own seeds ought to be at least somewhat adapted to your climate and soil and pests and methods. If a bad winter (or summer) kills everything in the ground, but you've saved your own seeds, re-establishing them from YOUR strain should retain any local adaptations and let you continue adapting them to your climate.

I say go with the above, and put in the best info you can, and then hopefully other gardeners will comment on what does and does not do well in their area, so we can get a better overall picture.

I really count on comments.I also comment on color accuracy.

Color accuracy? You mean, in descriptions or in pictures?

I was looking for some Lupines that might grow in my hot humid area and I found wild lupines will grow. I got the information from a list I found on the internet. Also list native trees, shrups, etc. for the selected region. Great source for hardiness. I found that American Meadows has the seeds, but I don't have time to look them up. Has anyone purchased from them before? Here is the link:

http://www.plantnative.org/rpl...

http://www.americanmeadows.com...

I sure haven't. Did you want that many seeds? If not, there's a lot more places that sell them.

I had luck with these particular flowers (I'm assuming it's the same kind of lupine, not a cultivar) when I was in Phoenix. Soaked the seeds over night and planted all the ones that sunk to the bottom of the glass. T'was gorgeous. I also love the leaf shape.

Correct, they are wild flowers. I could probably do better on eBay because American Meadows is kinda if-fie as a company. You would have to check out the WatchDog on DG. I would not mind giving them a chance, it's just seeds and I could easily save the seed for next years seed swap on Cubits. Sounds like you got a good tip as far as planting the ones that sink, that sounds like a great idea!! You should submit that tip to Trish! You might have something there and I sure will give it a try, thank you !!

You are so welcome!

This is a seed company I've heard some good stuff about from people who do a lot of seed starting:
http://www.swallowtailgardense...

This is also a really good site, and this guy knows his stuff:
http://www.jlhudsonseeds.net/S...

WOW

WhooHoo, I sure like those red ones.

I purchased a bunch of seeds from American Meadows for use in a fallow field in town. Natives, mixed and non. This is their forte and the process was painless and very successful. While not my thing, the folks who ran the project were very happy.

I'm thinking the ones listed as Texas Bluebonnets are probably pretty impervious to humidity = they hail from a *very* humid area.

The Texas Bluebonnets actually grow best in the parts of Texas that aren't quite so humid. They don't like Houston as well as Austin, for example. Unfortunately. (insert pouty face here) They might be very happy in Virginia, though.

Huh, Marylynn - I briefly lived outside of San Antonio and spent quite a bit of time in the Hill Country ... now I'm double checking my memory, I would swear I saw them blooming there.... 'Cause, yeah, it sure was humid!!!

Yep, they definitely have them in the Hill Country. However, compared to here that isn't very humid! LOL I guess we have different scales.