> I am not sure of which nasturtium do we speak when we
> want to have peppery leaves used for salads, and a compaion
plant for
> cucumbers
you are talking about tropaeolum, the one that also hast the
beautiful and delicious bright yellow, orange and red flowers
(great stuffed with some nutbutter or a piece of cheese).
> What is the difference between
> Nasturtium - Tropaeolum majus
> and
> water cress - Nasturtium officinale
well, they are 2 different plants, with tho only common feature
the peppery tast of the leaves - everything else is different.
most significant diff is propably, that watercress grows best
sumberged in (flowing) water - not sure that your cukes would
appreciated that. for more details of the differences please look
them both uip on http://www.pfaf.org