Rosemary Seeds Rosemary is a perennial evergreen shrub with blue flowers. It is a pungent and distinctive plant with a sweet, resinous flavor. Rosemary is ideal for a rock garden or the top of a dry wall. It is used for poultry, lamb, stews, and soups. This is one of the more difficult herbs to germinate. Until the plant is established, the grower level necessary is Advanced. Germination rates for rosemary can be very erratic. Germination: The seed takes a while to germinate so you need to start it about three months before the warm weather arrives. Place the seed onto a well drained base such as sand, vermiculite or very light potting mix. Cover the seed with a little more mix, water lightly and place the container in a warm location or onto a heat mat. Cover the container with plastic wrap until you see the seeds starting to emerge. As soon as you see the tiny rosemary plants starting to grow, it is important to give them a good light source and a warm environment. Do not expect germination of all the seeds as rosemary has a much lower germination rate than some other popular herbs such as basil.