David E. Ross wrote:


Be careful. Oregano and mint can be quite invasive. On the other hand,
sage, rosemary, and thyme behave very well.

Here in the frozen north, mint definitely needs a rhizome barrier.
Oregano is fairly well behaved, but putting down a barrier should give
peace of mind. But they should be used to cover ground, not in a pot.
We make herbal tea every night (so let me suggest lemon balm as well,
and that, too, needs a barrier), and a few square meters of herbs can
satisfy all the herb needs a family may have. Plus we marinate or add
herbs to just about everything we eat before dessert.


Try planting a few sage, which can grow somewhat shrubby.

Plant thyme as a ground cover; it's quite good between stepping stones
if the stones are spaced 2 inches (5 cm) or more apart.

or as a foundation plant.


Rosemary is available either as a ground cover or as a shrub. Either
would be good around olives. I have a rosemary shrub that is now 20
years old or more. It's taller than I am. The trunk is about 3-4
inches in diameter. The branches are twisted and very picturesque.

yes, I think rosemary as an accent plant has its merits. But the ground
cover varieties I have tasted were horribly bitter. so I vote shrub.
The other herbs with the exception of mint all can be made to look
good, though my experience is that sage grows in a full bush only in
full sun. Otherwise it might get rangy (this from experience in a
warmer climate, when I had just rosemary and sage).


Oregano can be kept under control in a large flower pot. It takes about
the same care as sage, rosemary, and thyme. They all require only a
moderate amount of water. Mint can also be kept under control in a
large pot, but it needs much more water.

--
David E. Ross
Climate: California Mediterranean
Sunset Zone: 21 -- interior Santa Monica Mountains with some ocean
influence (USDA 10a, very close to Sunset Zone 19)
Gardening pages at http://www.rossde.com/garden/