On Fri, 21 Feb 2003 10:01:23 GMT, "Anne Middleton/Harold Walker"
wrote:


.
| And the USDA zones are a damn-fool idea |
| Now, now, Nick, temper, temper. The USDA zones were devised with
| a specific purpose in mind, hardiness of *woody*

That is true, and I wish people would stop doing it./////////////
Nick, is that an all inclusive statement.....meaning that we in the USA
should stop using this valuable tool?????????

Some of my most valuable gardening books are of English origin but I would
never suggest chucking 'em out because they contain material of no value to
the parts of the USA where it is colder than hell in the winter time and
gardening, as you know it over there, does not exist......such utter
nonsense and tripe as planting broad beans in the autumn months to give a
head start for the following year or planting spring cabbage seedlings in
the autumn months..........perhaps I should reconsider and consign those
books to the scrap heap or the compost heap??????
HW.

You have entirely omitted attribution of the quoted material. In
a contentious thread like this one shows signs of turning into,
careful attribution and quote-marking is a sine qua non, as well
as being a courtesy.

--
Rodger Whitlock
Victoria, British Columbia, Canada

In article ,
(Rodger Whitlock) writes:
| On 21 Feb 2003 08:40:36 GMT, (Nick Maclaren)
| wrote:
| Rodger Whitlock writes:
|
| ...The USDA zones were devised with
| a specific purpose in mind, hardiness of *woody* material in the
| continental USA.
|
| Perhaps I am too stringent, but I regard anyone who invents such
| a scheme without thinking of its potential for extension as being
| a fool...at the very least they should have considered
| its relevance to herbaceous crop plants.
|
| Not really (imo). The only important herbaceous crop that
| over-winters, and for which hardiness is therefore an issue, is
| fall-sown wheat, afaik. The other big grain crop grown in the US
| is corn (maize), which is invariably sown in the spring.

Winter wheat is woody? Boggle :-)

More seriously, I agree that the vast proportion of the agricultural
crops are not herbaceous, but they are not woody either, and the
average extreme minimum is quite inappropriate. There are many,
FAR better, measures for those, INCLUDING simple latitude! So I can
assume that either they were living in some fantasy world or were
thinking about the minority of perennial agricultural crops.

While the majority of those are woody, it is NOT a dominating
majority, not by any manner of means. Strawberries, asparagus
and globe artichokes have been grown commercially and on a large
scale in the USA for a long time, and there are a fair number of
other crops that may have been.

| And it may be that the deviser realized that a system suitable
| for herbaceous material was impractical as their hardiness
| depends on many other factors than just temperature, whereas the
| hardiness of woody material (sc. fruit trees) is really dependent
| only on the winter low temperature.

Well, if that were true, it would be a justification for using
the scheme, though NOT for claiming its generality. But it is
not true.

The survival of fruit TREES is dependent FAR more on the average
daily minimum than the average extreme minimum - bark is quite a
good insulator, you know! - especially as the former is FAR more
closely correlated with how deeply the soil freezes. The confusion
arises because, in the contiguous USA though not more generally,
the correlation between the two is extremely high.

The survival of fruiting branches is probably more dependent on
the extreme low, but isn't the main issue anyway. The main issue
is the frequency of late frosts and their effect on the flowers,
as any fruit grower can tell you! And there are plenty of ways
to measure that much more directly.

| Horticultural material doesn't have enough economic importance to
| count in this kind of study.

Agreed. I was and am damning them for doing a bad job of what they
set out to do, not what other people may claim.


Regards,
Nick Maclaren,
University of Cambridge Computing Service,
New Museums Site, Pembroke Street, Cambridge CB2 3QH, England.
Email:
Tel.: +44 1223 334761 Fax: +44 1223 334679

Pete The Gardener wrote:

On Thu, 20 Feb 2003 10:39:43 GMT, "Anne Middleton/Harold Walker"
wrote:


"Nick Maclaren"
"Nick Maclaren" wrote in .
And the USDA zones are a damn-fool idea anyway, as they measure
///////////////// to repeat Nick, it is a useful tool but not the only one.


I don't find it to be much use, according to the USDA Zones I'm in
zone 10/11 here in London, but there are very few plants from these
zones that are worth trying.
--
Pete The Gardener

Hi Pete,
There must be some misunderstanding here.
Where did you get that info? IMHO, London is Z8/Z9:
http://www2.dicom.se/fuchsias/eurozoner.html
I think not even a sheltered garden in the center of Londen would be
Z11. That zone would mean, essentially: no frost at any moment, the
whole year through.
So I'm not at all surprised Z10/Z11 plants are not happy outside,
where you are...
Regards,
Roger.

On 21 Feb 2003 18:03:14 GMT, (Nick Maclaren)
wrote:


More seriously, I agree that the vast proportion of the agricultural
crops are not herbaceous, but they are not woody either, and the
average extreme minimum is quite inappropriate. There are many,
FAR better, measures for those, INCLUDING simple latitude!

Not really. If you look at a weather map of North America with
the temperature bands colored (or the USDA zone map, for that
matter!), you will see that they are *not* oriented east-west.
Indeed, on the left coast, the bands run north-south rather than
east-west. And in the south east, they run in a large curve that
aproximately parallels the coast from Texas to New England.

Judging from remarks in Donald Wyman's "Shrubs and Vines for
American Gardens", these zone maps were devised specifically for
ormnamental trees and shrubs. I was wrong in thinking that they
were devised for fruit trees. But they were definitely intended
for *woody* material, not herbaceous plants.

Wyman distinguishes the zone map devised at the Arnold Arboretum
from that devised by the USDA. And, might I add, that his words
imply that the USDA map was actually devised by the American
Horticultural Society and only published by the USDA. Your
disdain for it might not be too far off the mark after all.

--
Rodger Whitlock
Victoria, British Columbia, Canada

On Sat, 22 Feb 2003 12:22:34 GMT, Roger Van Loon
wrote:

Hi Pete,
There must be some misunderstanding here.
Where did you get that info?

The RHS Dictionary.

IMHO, London is Z8/Z9:
http://www2.dicom.se/fuchsias/eurozoner.html

This is probably true for much of London, though where my parents live
I would say 7/8, but I live in South Kensington, in central London,
and the climate is a fair bit different.

I think not even a sheltered garden in the center of London would be
Z11. That zone would mean, essentially: no frost at any moment, the
whole year through.

Most years we get either no frost or, at most, about half a degree of
frost. This year has been an exception, we've had temperatures below
freezing on about 8 or 10 nights, I think the worst was about -4C. We
haven't had it that cold for at least 6/8 years.

So I'm not at all surprised Z10/Z11 plants are not happy outside,
where you are...

Many Z10/11 plants will take short periods of freezing temps, what
they wont take are long periods of cold, but not freezing, temps with
loads of damp.

--
Pete The Gardener
A room without books is like a body without a soul.

Pete The Gardener wrote:

On Sat, 22 Feb 2003 12:22:34 GMT, Roger Van Loon
wrote:

Hi Pete,
There must be some misunderstanding here.
Where did you get that info?

The RHS Dictionary.

Strange. I see in the 1992 edition of the RHS Dictionary of Gardening
(ISBN 0-333-47494-5) they give Z8/Z9 for London, certainly not
Z10/Z11.

IMHO, London is Z8/Z9:
http://www2.dicom.se/fuchsias/eurozoner.html

This is probably true for much of London, though where my parents live
I would say 7/8, but I live in South Kensington, in central London,
and the climate is a fair bit different.

I think not even a sheltered garden in the center of London would be
Z11. That zone would mean, essentially: no frost at any moment, the
whole year through.

Most years we get either no frost or, at most, about half a degree of
frost. This year has been an exception, we've had temperatures below
freezing on about 8 or 10 nights, I think the worst was about -4C. We
haven't had it that cold for at least 6/8 years.

Yes, I heard of spots in Central London where you even have large
Phoenix canariensis.

So I'm not at all surprised Z10/Z11 plants are not happy outside,
where you are...

Many Z10/11 plants will take short periods of freezing temps, what
they wont take are long periods of cold, but not freezing, temps with
loads of damp.

Still, then it would be useful to know that a plant is rated Z10/Z11
and not Z7, I think.


--
Pete The Gardener
A room without books is like a body without a soul.

True, but my wife is always complaining that there are way too many
books in all the rooms of our house, no space left :-)

Regards,
Roger.
--


You're welcome to visit my gardening page:
http://users.pandora.be/roger.van.loon/gardenp.htm

In article ,
Rodger Whitlock wrote:
On 21 Feb 2003 18:03:14 GMT, (Nick Maclaren)
wrote:

More seriously, I agree that the vast proportion of the agricultural
crops are not herbaceous, but they are not woody either, and the
average extreme minimum is quite inappropriate. There are many,
FAR better, measures for those, INCLUDING simple latitude!

Not really. If you look at a weather map of North America with
the temperature bands colored (or the USDA zone map, for that
matter!), you will see that they are *not* oriented east-west.
Indeed, on the left coast, the bands run north-south rather than
east-west. And in the south east, they run in a large curve that
aproximately parallels the coast from Texas to New England.

I suggest rereading what I said! What you say is quite correct,
but irrelevant. The vast proportion of agricultural crops are
grown as annuals, where it is the length of growing season and its
cumulative heat and light that matters, and simple latitude is a
MUCH more reliable indicator for those EVEN within the USA!

Globally, of course, it beats the daylights out of USDA zones as
an indicator of which agricultural crops are appropriate. Look at
any good atlas and see - the bands hit you between the eyes.

Wyman distinguishes the zone map devised at the Arnold Arboretum
from that devised by the USDA. And, might I add, that his words
imply that the USDA map was actually devised by the American
Horticultural Society and only published by the USDA. Your
disdain for it might not be too far off the mark after all.

Interesting.


Regards,
Nick Maclaren,
University of Cambridge Computing Service,
New Museums Site, Pembroke Street, Cambridge CB2 3QH, England.
Email:
Tel.: +44 1223 334761 Fax: +44 1223 334679