What are the purple weeds in my garden?

Answered by Stephen Mosley

Purple deadnettle (Lamium purpureum) is a common annual weed that can often be found in gardens. It is part of the mint family, which helps explain why it can be such a nuisance. This plant is an aggressive grower and tends to spread rapidly wherever it finds suitable conditions.

One of the distinguishing features of purple deadnettle is its purple-colored leaves and flowers, hence its name. The leaves are typically triangular or heart-shaped with serrated edges, and they have a velvety texture. The flowers are small and tubular, arranged in clusters along the stem. While the flowers can vary in color from pink to purple, they are usually a vibrant shade of purple.

Purple deadnettle is an annual plant, meaning it completes its life cycle within a single year. It typically germinates in the spring and grows rapidly throughout the summer months. By late summer or early fall, it produces seeds before dying off. These seeds can then lie dormant in the soil until the following spring when they germinate and start the cycle anew.

One of the reasons purple deadnettle can be such a problem in gardens is its ability to spread quickly. It reproduces both through seeds and by sending out runners known as stolons. These stolons can root wherever they come into contact with the soil, allowing the plant to form dense mats and outcompete other plants for space, nutrients, and light.

Purple deadnettle is also known for its adaptability to different growing conditions. It can thrive in a variety of soil types, including sandy, loamy, and clay soils. It can tolerate both moist and dry conditions, making it a resilient weed that can colonize a range of environments.

In my own experience, I have encountered purple deadnettle in my garden and found it to be quite persistent. It seemed to pop up in areas where the soil was bare or where other plants were struggling to grow. I noticed that it particularly liked areas with partial shade, such as under trees or along the edges of my garden beds.

To control purple deadnettle in your garden, there are several strategies you can employ:

1. Hand-pulling: If the infestation is relatively small, you can manually remove the plants by pulling them out from the root. It is important to ensure you remove as much of the root system as possible to prevent regrowth.

2. Mulching: Applying a thick layer of organic mulch around your plants can help suppress the growth of purple deadnettle. Mulch acts as a barrier, preventing sunlight from reaching the weed seeds and inhibiting their germination.

3. Herbicides: In severe cases, herbicides can be used to control purple deadnettle. Selective herbicides that target broadleaf weeds, such as those containing 2,4-D or dicamba, can be effective. However, it is important to carefully follow the instructions on the label and avoid spraying near desirable plants.

4. Improving soil health: Purple deadnettle tends to thrive in nutrient-poor soils, so improving the fertility of your garden soil can help prevent its growth. Adding organic matter, such as compost or well-rotted manure, can improve soil structure and provide essential nutrients for your desired plants, making it more difficult for weeds like purple deadnettle to establish themselves.

By employing a combination of these strategies, you can effectively manage and reduce the presence of purple deadnettle in your garden. However, it is important to be persistent and vigilant, as this weed can quickly bounce back if not adequately controlled. Regular monitoring and proactive management will help keep its spread in check and maintain the health and beauty of your garden.