Is Lavender Invasive or Does It Just Spread?
Explore the growth habits of lavender to understand if it's truly invasive or just a plant that spreads predictably and is easily managed in the garden.
Lavender is a popular choice for its fragrance and beauty, but many gardeners worry it might take over their garden beds. In most parts of the world, lavender is not considered an invasive species because its growth habits do not harm the surrounding environment.
Understanding Spreading Versus Invasive Plants
The term “invasive” has a specific ecological definition. A plant is classified as invasive if it is non-native to an ecosystem and its introduction causes, or is likely to cause, environmental or economic harm. These plants can outcompete native species for resources, disrupt food webs, and alter the natural landscape.
In contrast, many garden plants are vigorous growers without being ecologically harmful. They may expand quickly within a garden, requiring regular maintenance to keep them in check. A classic example is mint, which spreads through underground runners but is not considered a threat to native ecosystems. This differs from a plant like Kudzu, an invasive species that can smother native vegetation.
How Lavender Grows and Spreads
Lavender is a woody, clumping perennial, meaning its base grows larger and more woody each year. It does not spread through underground runners like mint. Lavender’s primary method of spreading in a garden is through self-seeding. Under the right conditions, like full sun and dry, well-draining soil, seeds from spent flowers can fall and germinate.
Some varieties of lavender, like English lavender (Lavandula angustifolia), may self-seed more readily than others. While not considered invasive in most regions, there are exceptions. For instance, Italian lavender (Lavandula stoechas) has been declared a weed in some parts of Australia because it can spread into the natural environment and displace native plants. A plant’s classification as invasive is dependent on the specific environment.
Keeping Lavender Contained
Managing lavender’s spread is straightforward. The primary method to prevent unwanted seedlings is deadheading, which involves snipping off flower stalks after they have bloomed but before they produce seeds. This not only controls the plant’s spread but can also encourage a second bloom.
Annual pruning is another practice for keeping lavender healthy and manageable. In early spring, cut back established plants to encourage new growth and maintain a compact shape. If any unwanted seedlings do appear, they are easy to identify and remove from the garden.