Forget-me-nots are cherished garden additions known for their delicate, true-blue flowers that appear en masse in the spring landscape. This widespread popularity is often accompanied by confusion regarding the plant’s vigorous spreading habit. Understanding whether these plants are merely aggressive or pose a true ecological threat requires looking closely at the different types of forget-me-nots. The plant’s behavior is highly dependent on its specific identity and its method of reproduction, which determines how much management it will require in a cultivated space.
Which Forget-Me-Not Are We Talking About
The common name “forget-me-not” actually covers several species within the Myosotis genus, and their growth habits vary significantly. The most familiar type in garden settings is often the woodland forget-me-not, Myosotis sylvatica, which is typically grown as a biennial or a short-lived perennial. This species spreads primarily by producing a massive number of seeds that readily self-sow throughout the garden, sometimes forming a dense blue carpet.
Another species, the water forget-me-not, Myosotis scorpioides, exhibits a fundamentally different growth pattern and is often found near ponds or streams. This true perennial spreads not only by seed but also through creeping horizontal stems called stolons or rhizomes. This vegetative reproduction allows it to colonize wet areas rapidly and form dense, persistent clumps. Because the species’ spreading mechanisms differ, identifying which one is in the garden is necessary before determining the required control strategy.
The Difference Between Aggressive and Invasive
The confusion surrounding forget-me-nots often stems from the loose use of the terms “aggressive” and “invasive” in horticultural conversation. In the context of a garden, an aggressive plant is one that spreads quickly and vigorously within a cultivated area, making it a nuisance for the gardener. This rapid growth can be due to prolific self-seeding or fast-spreading root systems, but the impact is generally confined to the property boundary. Most garden forget-me-nots, particularly M. sylvatica, fit this description, as they are simply enthusiastic self-seeders.
The term “invasive,” however, carries a specific legal and ecological definition that applies to non-native species. A plant is classified as invasive when it spreads rapidly and causes environmental or economic harm by displacing native species in natural ecosystems. While the woodland forget-me-not (M. sylvatica) can escape gardens, the water forget-me-not (M. scorpioides) poses a greater ecological threat. This water variety is legally restricted in multiple US states because it can choke waterways and rapidly form monocultures that displace native wetland vegetation.
Practical Methods for Garden Control
Managing the aggressive tendencies of forget-me-nots requires targeting their primary method of reproduction. For the common self-seeding variety, Myosotis sylvatica, the most effective control method is a practice called deadheading. Removing the spent flowers before they have a chance to set seed prevents the plant from dispersing the next generation of seedlings throughout the garden. This action redirects the plant’s energy away from seed production and limits its spread immediately.
If the plant has already established itself widely, mechanical removal by hand-pulling or hoeing is a straightforward option, especially when the soil is moist. It is important to remove the plants before the seed capsules ripen to avoid scattering more seeds during the process. Applying a layer of organic mulch around the plants can also help suppress the germination of any stray seeds that may have fallen to the ground.
Controlling the water forget-me-not, M. scorpioides, is more challenging due to its ability to spread vegetatively via stolons. For this variety, simply pulling the top growth is not enough, as the root system must be completely removed to prevent resprouting. If the plant is colonizing a boggy area or pond edge, continually digging up the spreading roots and stolons is necessary for long-term containment. Gardeners who find the maintenance too demanding may consider replacing the forget-me-not with a native blue-flowered alternative that requires less intervention.