Rosemary is a fragrant, evergreen shrub known botanically as Salvia rosmarinus, widely valued in both cooking and traditional medicine for its distinct pine-like aroma and flavor. Many people seeking to harvest their own supply often ask about its specific growing season, assuming it follows the same cycle as annual herbs. However, the concept of a limited “season” for harvesting rosemary is generally a misunderstanding of its growth habits. Its availability and quality are governed by its perennial classification, making it accessible year-round in many contexts.
The Perennial Nature of Rosemary
Rosemary is classified as a perennial, meaning its woody structure persists and grows over multiple years, unlike annual plants such as basil, which complete their life cycle in a single season. As an evergreen, rosemary retains its needle-like leaves throughout the entire year, even during cooler months when growth slows considerably. This characteristic allows gardeners in appropriate climates to harvest small amounts whenever needed. The shrub’s resilience and longevity mean it does not experience the traditional “end of season” dieback common to many garden herbs.
Optimal Harvesting for Peak Flavor
While fresh rosemary is available year-round, the concentration of its aromatic essential oils, which contribute to its flavor, fluctuates with the plant’s growth phases. The most potent and flavorful rosemary is typically harvested during the late spring and summer months when the plant is actively growing. The highest oil content generally occurs just before or during the plant’s flowering stage, a biological period when the plant is dedicating significant energy to reproduction.
Harvesting Technique
For the best quality, harvesting is ideally done in the mid-morning after the morning dew has completely evaporated from the leaves but before the hottest part of the day. This timing ensures the aromatic oils are at their maximum concentration within the foliage. When taking cuttings, snip the tender, supple new growth tips, which are typically lighter green and easier to chop for fresh use. Avoid cutting into the woody, older stems, and never remove more than about one-third of the entire plant at any single time, allowing the shrub to recover and produce more growth.
Regional Climate Influences on Growth
The ability to harvest rosemary consistently is heavily influenced by the regional climate, specifically a location’s USDA Plant Hardiness Zone. In warmer, Mediterranean-like regions, generally zones 8 through 10, rosemary is a true outdoor evergreen that can be harvested throughout the winter with minimal interruption. The steady, mild temperatures in these areas permit continuous growth, though it slows in colder months.
In colder climates, typically zones 6 and lower, rosemary cannot survive the harsh winter outdoors and is instead grown as an annual or brought indoors. When temperatures drop below freezing, the plant’s growth essentially stops, and it may enter a state of semi-dormancy. Gardeners in these areas often move their potted rosemary plants inside to a bright, cool location to continue light harvesting or simply overwinter the plant until spring.
Storing and Preserving Fresh Rosemary
Once harvested or purchased, fresh rosemary can be kept viable for short periods using simple refrigeration techniques. For longer-term preservation, drying or freezing methods are effective.
Short-Term Storage
Wrapping the sprigs in a slightly damp paper towel and placing them inside a sealed plastic bag or container in the refrigerator’s crisper drawer can maintain freshness for up to two weeks. Alternatively, the stems can be placed vertically in a glass of water, covered loosely with a plastic bag, and refrigerated.
Long-Term Preservation
For longer-term storage, the herb can be dried by hanging small bundles upside down in a warm, well-ventilated space until the leaves are brittle. The leaves can then be stripped from the stem and stored in an airtight container for future use. A freezing method that preserves the fresh flavor involves stripping the leaves and packing them into ice cube trays with olive oil or water before freezing.