Back when my mother was alive, she was able to take a small pot of
oregano from the nursery and grow it into large perennial shrub that
we could harvest from all year.

Now that I've got a home and garden of my own, I've been trying to do
the same thing. My last several attempts have been pathetic failures,
however. I generally buy a well established pot of oregano, transplant
it into a larger pot, and let the plant grow.

Unfortunately, what generally happens is that rather than sending up
new stems to fill the new pot, the old stems simply get tall, the
lower leaves die off, and the plant gets leggy. Early in summer, the
plant goes to flower, and what was once a robust (if leggy) plant
rapidly dies back.

Lately, it has occurred to me that I really ought to be pruning the
plant if I want it to expand into a large bush. However, I know very
little about pruning techniques. Where and how much should I cut back
and when?

Right now my present oregano plant is fairly tall but leggy and going
into flower. If from this point I want to train it into a large shrub
that will fill the pot I've transplanted it into, what steps do I
take?

Also, are the pruning techniques for oregano generally applicable to
other herbs?

Thanks,
Peter