"John Lloyd" wrote in message
...
In article , Kay Easton
writes
In article , Mike Day
writes

Point of interest: we have a wisteria that could hardly bloom more
profusely, but it has never ever been pruned, or perhaps, more strictly
speaking, it prunes itself. It grows in a full size barrel (36 gallons
I think), where it has sat undisturbed for at least the last 20 years
(it has bloomed for most of them), with an occasional dose of
Phostrogen. It is supported against the house wall by wire up to a
height of around 15 ft. thereafter its on its own and tends to spread
slowly outwards, and sideways within the limits of the wire. New
shoots, finding no where to go, tend to die back. I'm not sure what is
the lesson - perhaps it is to be cruel!

There is a good technical reason explanation for this. I posted a long note
about it some years ago here, I can't find the original, but briefly:

Wisteria grows naturally in forests. They climb to the top of the canopy and
flower in the light. The mechanism biological mechanism to stop them
flowering below canopy height is suppression by hormone flow from the
growing tip (apical dominance is the technical term).

How do they know to flower? The leaders flops over, and the flow of hormone
from the apical bud is disrupted.

The pruning regime normally followed is designed to trick the plant into
thinking that it has reached the canopy top and flopped over ie cutting off
the growing tip disrupts the hormone flow.

The situation you describe mirrors closely the natural growing pattern of
Wisteria in the wild. Mature plant, flopping over - hence it flowers without
pruning!


Roofing plants on Pergolas often show the same "flowering without pruning"
pattern - which I suppose is why there is ofetn conflicting advice on how to
get them to flower.

But, if you want an immature plant to flower or to clothe the legs of a
pergola with flower, then pruning is needed.

pk