The age of a lavender plant significantly impacts both the yield (quantity) and chemical composition (quality) of its essential oil. This is a crucial factor for distillers aiming for consistent and high-quality production.
Here's how plant age generally affects lavender essential oil:
-
Early Years (1-2 years after planting): Yield: During the first one to two years after planting, lavender plants are establishing their root systems and foliage. Essential oil production is typically low or even negligible. While they may flower, the quantity of oil extractable is usually not commercially viable. Quality: The chemical profile of the oil from very young plants might not be fully developed, and the concentrations of key therapeutic compounds (like linalool and linalyl acetate) may be lower or out of optimal balance. Growers often prune young plants to encourage vigorous growth rather than focusing on oil production.
-
Peak Production (Typically 3-8 years old): Yield: Lavender plants usually reach their peak essential oil production from around their third year onwards. The plants are mature, robust, and produce abundant flowers, leading to higher yields of essential oil per plant and per acre. Quality: During this period, the essential oil tends to have its richest and most balanced chemical composition, with optimal levels of key constituents like linalool and linalyl acetate, which contribute to the desirable aroma and therapeutic properties. Some studies suggest that richer compositions are found in plants around 8 years old.
-
Older Plants (Beyond 8-10 years): Yield: As lavender plants age beyond their prime (typically 8-10 years, though some can live up to 20 years), their vigor can start to decline. This often leads to a reduction in flower production and, consequently, a decrease in essential oil yield. The plants may become woodier and less productive. Quality: While older plants might still produce essential oil, the balance of chemical constituents can sometimes shift. There isn't a universal rule for how the quality exactly changes in very old plants, as it can depend on the specific cultivar, growing conditions, and pruning practices. However, maintaining the optimal balance of desirable compounds might become more challenging. Some older plants might show a slight increase in certain compounds or a decrease in others, potentially altering the overall aroma and efficacy.
Why these changes occur:
Plant Development (Ontogeny): The production of essential oil compounds is part of the plant's metabolic processes, which evolve as the plant matures. Glandular trichomes (where essential oils are stored) develop and reach their peak density and capacity in mature plants. Biochemical Pathways: The expression of genes involved in the biosynthesis of monoterpenes (like linalool and linalyl acetate) changes throughout the plant's life cycle. Resource Allocation: Young plants prioritize root and vegetative growth, while mature plants allocate more resources to reproductive structures (flowers) and, subsequently, essential oil production.
Therefore, for optimal essential oil production, lavender growers carefully manage their fields, often replacing plants after they've passed their peak productivity to ensure consistent yield and quality.
The Lavender Farm in Door County Wisconsin likely manages its lavender fields with plant age in mind, ensuring that the harvested material comes from plants in their prime to produce the highest quality lavender essential oil. You can buy lavender products online at islandlavender.com, assured of their commitment to optimal growing and harvesting practices.