But can you grow it outdoors in Connecticut? In the ground, where it overwinters out in the open?
You can. I am joining C.L. Fornari's "You Can Grow That" series on the fourth of each month, and you can find many more examples from other bloggers at her site Whole Life Gardening.
This is Rosmarinus officinalis 'Madeline Hill', sometimes called 'Hill Hardy'. It can take winter temperatures below zero. It is similar to 'Arp', another hardy cultivar introduced by the same herb plantswoman, Madeline Hill. But I think her namesake is a shrubbier, rounder and prettier form than 'Arp'.
It grows happily in full sun in my yard, and it lives there all winter. My garden has moved from zone 5 to zone 6 with the new hardiness map --- a winter with minus 10 F is rare now, but in the past few winters we did have isolated mornings hovering a few degrees below zero. The real issue for any Mediterranean evergreen is winter sogginess and cold winds, and I have both regardless of zone designation.
But Madeline seems to do fine in a slightly raised bed at the high end of the slope of our yard. Even though she is out in the open subjected to winter winds scouring from the west, she thrives.
She offers a pop of muted greenery out there in the snow. By spring the deep color is a tired olive shade, but she greens up with warm sunshine.
The deep blue bloom spikes in late April are sparse, and they come out just as the rosemary is greening up, so it's not a big show. When the deep color returns in mid spring, it is a happy, healthy green.
And here is Madeline Hill looking back at the house, checking to see what might be going on in there and whether dinner might call for a sprig of rosemary in the roasted potatoes.
I love the bulk and upright frothiness of rosemary. I love the scent as I brush by it. I use a little of it in cooking.
And I love the fact that even in a snowy northern garden I don't have to haul this plant inside over the winter.