In article , Tony Morgan
writes
In message , Janet Baraclough
writes
I've been growing clematis for 47 years, I can assure you that if you
plant a set of leaf nodes below the surface and you have a wet spell
within a week or so, then you can expect to get rot and lose the plant -
not necessarily but there's a good possibly..

I've always planted clematis deep for the same reasons Rachel has
given, and find they do very well; even though they invariably have a
wet spell soon after planting. I live in the extremely wet west of
Scotland; rainfall at least 70" pa and rising.

Experts are divided as to what causes Clematis wilt (which seems to be
the underlying motive for deep planting).

There is certainly some discussion about this, but the accepted view is
that wilt, *also known as stem rot* is caused by a "a vulnerability to a
number of fungi of which Ascochyta clematidina (Phoma clematidina Thüm.)
and Coniothyrium clematidis-rectae have been identified". [1] Most
particularly, Phoma clematidina, but other phoma have been found in
wilted clematis stems. Small flowered hybrids and species are very
resistant to the virus.

The reason for the deep planting recommendation is that it is believed
by some (many?) to be due to insufficient water in the flowering season
- usually accompanied by a fungal infection (opinion is divided as to
which precedes which), as well as "insurance" in getting new growth if
wilt destroys the plant.

A plant under stress is a vulnerable plant. If you starve your plant of
water, it will be more susceptible to disease & bugs. Planting deep
does, indeed, give you a considerable measure of 'insurance' because of
the growth habit of hybrid clematis. If you don't have any leaf nodes
under the soil, if anything should happen to the top of the plant (not
just wilt), the dormant nodes will shoot. Indeed, if clematis didn't
like being planted deep from the cutting stage onwards, you couldn't
propagate them in the first place. Furthermore, if you didn't bury the
stem with buds, you wouldn't get multi-stemmed plants. It is a very
good long-term survival strategy.

So, to put it simply, if you have no buried leaf nodes & you lose the
top of the clematis (for whatever reason), your plant is to all intents
and purposes dead. Hybrid clematis cannot shoot from the roots
(although atragenes can). Oddly enough, the roots will continue to grow
for years, but there will be no top growth.

It is believed that wilt-virus (easier to spell than the Latin) enters
the plant through cracked or damaged stems & leaves and we know from our
own experience that it always works up the plant, never down. It
appears to block the stem and prevents water being taken up through the
system. The nodes you bury will be safe - the plant above ground is
not. If you catch it quickly enough, it is possible to strike cuttings
from a clematis affected by wilt & have perfectly healthy plants.

Its my view (shared by others)

Whom?

that its better to address the cause than
to adopt the "insurance" view of deep planting that can often cause
rotting of the stem if a long wet spell follows planting.

Addressing the cause is the obvious solution which is why deep planting
is recommended as well as planting well with plenty of food & water in
order to create a healthy plant. As we all know, a healthy plant is a
disease resistant plant.

And about these 'long wet spells' you speak of? We live in the UK -
it's hardly a rare occurrence for most of us.

Clematis wilt (I've never ever experienced it myself) can, in my view,
be avoided by well watering in the flowering season.

If you've never experienced it, how do you know?

And if wilt appears
can invariably be rectified by the application of Benomyl (Benlate).

No it can't. As any fule no, Benlate was banned in the UK & the US some
years ago. There is no useful 100% chemical prevention for wilt and, in
spite of what you seem to believe, Benlate didn't fix it either.
Systemic fungicides may help - but not much.

Clematis wilt invariably occurs in (or immediately before) the flowering
season, and by that time the root system is sufficiently developed to
regenerate the plant by the next season - even if the Benomyl doesn't
restore the plant that season.

The root system can't regenerate anything if there are no shoots to
regenerate from. And wilt, generally speaking, affects only one group
of clematis - some of the early large flowered hybrids. And it doesn't
affect them all that much. Often, what appears to be wilt, is something
entirely different. The plant being battered by wind, slugs or mice
eating through the stems, etc.

Benomyl or any other fungicide does not *restore* the plant. It has
nothing to do with whether the plant will grow again or not. But the
buried leaf nodes have *everything* to do with it.

IMHO more clematis are lost in the first season through rotting of
buried portions of the newly planted stem following wet periods
(especially in heavy or badly drained soil), compared with those that
are lost by wilt (which rarely occurs at planting time). This is why I
disputed the advice given.

But you're not supposed to plant them in heavy, badly drained soil.
They don't like it. Basically, they drown. Unless it is a marsh or
water plant adapted to that environment, if your soil is waterlogged and
heavy, with no oxygen, your plant can't breathe.

You are disputing advice that is tried and tested not just by me, but
the whole clematis industry, for generations past and whilst I agree
with Charlie in that advice has to be a 'fits all' basis, people often
break the 'rules' successfully. Nevertheless, these are exceptions, not
norms. I know of clematis armandii growing on a North wall in the
Pennines - but it's not a position I would recommend for general
planting as I know of many more that have failed in similar
circumstances.

The authority for my information on planting depth comes from: Graham
Stuart Thomas, Christopher Lloyd, Barry Fretwell, Christopher Grey-
Wilson, Raymond Evison, Mary Toomey, Malcolm Oviatt-Ham, Ruth Gooch,
Sheila Chapman, Dr.John Howells, Everett Leeds, Geoff Hamilton (bless) -
they *all* recommend deep planting, most particularly for hybrids.
Every clematis nursery in Britain says the same. So does the British
Clematis Society & the International Clematis Society.

I have not read, anywhere, that planting clematis with no extra depth is
a recommended practise, so please list your sources of information
(other than yourself, of course).

I mentioned your interesting theory to Grandad, who has grown more
varieties of clematis for a lot longer than you. It made him laugh -
but he was not amused to hear of your implication that our advice (and
therefore the advice of every clematis nursery) is deliberately
misleading in order to sell more plants. The only printable thing he
said was 'even a fool can be thought a wise man ... if he keeps his
mouth shut'.

[1] Dr. John Howells' Work on Stem Rot (Clematis Wilt)
--
Rachel
Clematis Web Site
http://www.ukclematis.co.uk/