White Sage Growth Habit

I have a white sage (Salvia apiana) that a friend of mine gave me years ago. It is growing well and has come up every year now in the spring.The question I have is how come it will not grow as big as it looks in books that I have seen. It should look like a shrub, but mine is more like a thin twigged weed. The leaves are far apart and the stems only grow 18 to 24 inches tall, then they flower. It has no resemblance to a shrub. Although it has spread rather well by root. I have also ordered another plant from you to compare the two to make sure that it is the right variety. Could it be the short growing season that I have in my area. I live in Torrington, Connecticut, USA. What can I do to make it grow to the expectancy that I have for it.
I have a garden sage plant, that I've had for 2 years now and it resembles a small shrub.It seems to look more like the white sage that I expect, except for the fact that it's green.
Can you give me some information that might help me with this. Maybe it would be better if I grew it inside?

Salvia apiana is hardy in zones 7 to 9. Connecticut is mostly zone 6 with a bit of zone 5 and 7 in certain areas. You might make the true white sage survive the winter by putting it in a sheltered spot and mulching it well in the winter if you live in zone 6, but if you are in zone 5 the true species is unlikely to have survived several winters. If you live in zone 5 or 6 it would be better to grow the plant in a large pot and move the plant, pot and all indoors in late fall or early winter for the rest of the winter.
Have you checked the picture in our 2002 catalogue on page 47? If you grow the plant under low light conditions it would get thinner and the leaves would be further apart on the stems. They need full sun.
You have not mentioned what kind of soil you have. Sages like good drainage. If your soil is too clayey it would result in poor growth and would require the addition of sand and humus to result in optimum growth.