Hi, Cate. "Perennial" simply refers to a plant that is capable of completing 3 or more growth cycles. "Perennial" does not speak to cold-hardiness, which is what you are actually addressing in your question. If your lavender is Lavandula angustifolia, it will likely be hardy w/o protection, but if not, it may not be. As you can see, you didn't offer enough info for a conclusive answer. The rosemary will assuredly need protection & even an unheated garage will be too cold. A brightly lit and cool room would be best as this plant appreciates a cool rest in winter. Al

I know it is hard without a pic of it! And, I realized when you replied that I forgot to mention that it is not fragrant at all. Even though it looks and feels like some type of herb. So, not a sage. By looking at it you would think sage or lavender with the grayish leaves and the flowers. Thanks for replying! I have been trying to do Google searches to try and find out what it is, and how to propagate it. I tried a hardwood cutting for my MIL, but it didn't take. Sred

In my zone 5 location, I have to overwinter rosemary in my house. The plant is fine outside with temperatures in the upper 20s. I am guessing that the fate of your plant is due to the lows in the teens. Your well established deep roooted plant should be able to withstand long periods without water. I think you can save your plant with some drastic pruning to remove the brown stems. If this were mine, I would be anxious to root some more cuttings. After a few years my plants become tall and leggy and it is time for them to be replaced.

I don't know about growing rosemary from seed, but last spring I got 3 little rosemary plants about 8 inches tall and put them in some mostly sandy soil by my front door in full sun. They pick up water from the irrigation for the shrubs, but that sandy soil drains instantly. This year, 12 months later, they're about 4 feet tall. I've trimmed one side back drastically and it's bouncing back. By this time next year I'll have the prettiest smelling hedge in the world. Give your rosemary lots of sun, WELL-drained soil and regular moisture but no wet feet, and then stand back. I'll let the other folks here talk about lavender, because it's too hot and humid in my yard for it, although I'd love to be able to grow it. Good luck!