Jane Ransom wrote:

In article , Roger Van Loon
writes

They do??
The ones I have don't!!

Nor mine!

They must be totally out of date then.

Now, hang on a minute there.
Hold on to your horses.

I don't have any :-)

What in hell's name do you mean by 'out of date'??
I never heard such a stupid, nonsensical expression when referring to
gardening books!!!!!!!!!!!
A plant which needed conditions x, y and z a couple of centuries ago,
still needs conditions x, y and z today!!!!!!

Hope your own herd has not stampeded, and you're still holding on to
them :-))
I think we are talking here about the winter hardiness of plants, and
then I'm sure the basic info about a certain plant is only to be found
in authoritative plant encyclopedias and dictionaries (where else?)
But, sadly, those works are out of date after a relatively short time,
for several reasons.
First, the botanists think it necessary to regularly change the names:
they always find some reason (in fact I think it's mostly to let us
know how important they are themselves). I still have the old 1977
six-volume edition of the RHS "Dictionary of Gardening" (not so very
old after all), and it's amazing to see how relatively few of those
plant names are still valid at this moment. So, if you have the (now)
correct name of a plant, and you look it up in there, there's a good
chance you won't find it.
Secondly, new plants are being brought into cultivation all the time,
not to be found in those older works. (Just look at the list of new
Arisaema's).
Thirdly, I would not underestimate the value of new findings,
especially with hardier varieties of several species and hybrids being
introduced all the time. For example, Kadsura japonica and Bignonia
capreolata were not at all considered hardy some years ago, in fact
they have proved to be bone-hardy in my garden (no wonder, I see both
of them are now rated Z7 :-)))

I regularly use my late father in law's book on pruning shrubs -
published in 1966 - never found one better. In fact some of the old
remedies are far better than modern stuff - much more environmentally
friendly.
I have two RHS books, one published 1999 and one 2000, several Hessayon
books all of which I find invaluable and not one of them so much as
mentions USDA hardiness zones. Why should they waste time and effort
writing stuff which is of no use to us? Incidentally, while at a garden
centre yesterday, I had a look at a few books - didn't find any
references to USDA hardiness zones.

Mmm - were those serious plant encyclopedias, that is, authoritative
books that you would want to check, to learn about the growing
conditions and hardiness of special plants? (Not that I want to imply
other books can't be useful, in their own way)

I agree with other people in this thread - if our authors are now
including USDA hardiness zones in their books, it has absolutely nothing
to do with the relevance of that information to UK gardens but
everything to do with profits and markets for the publishers.

Of course, I'm sure that does play an important role, too.

--
Jane Ransom in Lancaster.

Roger Van Loon in Flanders.

--
Walk tall, walk straight, and look the world right into the eye.
You're welcome to visit my gardening page:
http://users.pandora.be/roger.van.loon/gardenp.htm