I hold National Plant Collection ® of Satureja.
The genus Satureja is native to the Mediterranean region and
comprises highly aromatic species of mostly low growing
sub-shrubs. Commonly grown in British gardens are
Satureja montana, winter savory; Satureja hortensis,
summer savory, an annual; and Satureja spicigera,
creeping savory. Both S. montana and S. hortensis were
introduced to Britain by the Romans and were two of the
plants the English colonists took with them to America to
remind them of the gardens they left behind.
Savory was used by the Romans to flavour vinegar and
the Ancient Egyptians used it as a love potion. It is
mentioned by Shakespeare in 'The Winter's Tale'.
Thyme differs from Satureja in that it has a period of new growth in late winter early spring,
prior to flowering between May and August, followed by a period of new growth in late summer and is
evergreen in the winter. Satureja does not flower until late August and September,
by which time it is too late for any new growth.
It therefore behaves like a sub-shrub, dying down completely to tiny resting buds at the base of each stem.
Plants should be pruned hard to this resting bud in late spring, unlike
thymes which are pruned immediately after flowering.
The plants then grow throughout the summer and flower as summer ends and autumn begins.
In my opinion this characteristic should be regarded as the major factor in determining delineation
between the genera Thymus and Satureja, rather than flower shape.