I use organic fertilizer, which also builds the soil while feeding the plant. Too much fertilizer promotes fast, weak growth that will not be as flavorful. Rosemary, basil, oregano and other bushy herbs should be pruned lightly and regularly to promote fullness. Herbs are among the prettiest plants in our yard. The prostrate rosemary cascades over the edge of a limestone rock wall and is in bloom just about year round.
Bumblebees are regular visitors to the small blue flowers.
Pineapple sage sports showy red flowers in autumn, and it is always a joy to watch hummingbirds and yellow sulfur butterflies sipping its nectar. Bronze fennel is host to the caterpillar that will become the graceful black swallowtail butterfly. And rue, another perennial herb, is host to the giant swallowtail. Perhaps my favorite herb is African blue basil. I don't use it in cooking because I don't enjoy its flavor as much as sweet or spicy globe basil, but I have observed more colorful pollinating insects on the flowers of this plant than any other in our yard.