Answer: You can pick a sprig or two any time to use fresh. Fresh herbs have lots more flavor than dried, so it doesn't take much to flavor a dish.
The basil should be cut back periodically to stimulate new growth and prevent it blooming. Once it blooms, the flavor can deteriorate and since it is an annual, it tends to decline after blooming.
Rosemary would be selectively pruned (remove overly long branches by cutting deep inside the plant) or can be lightly sheared during spring or summer. If grown outdoors in the garden, do not prune it in the fall as this can stimulate late growth and reduce winter hardiness.
Sage is usually cut back quite hard after it blooms in the spring, and cut once or twice again later in the season. (The harvest would be dried.) This stimulates branching and helps it stay dense.
Oregano is usually trimmed back hard periodically to keep it compact and prevent it from blooming and setting seed. (It can seed about prolifically.)
Enjoy your herbs!
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