As a gardening and landscaping expert, I can tell you that purple asters, also known as Aster novae-angliae or New England asters, are not typically considered invasive by the United States Department of Agriculture (USDA). However, it’s important to note that even though they may not be labeled as invasive, they can still be aggressive growers if not well managed, leading to potential headaches in the garden.
Purple asters are native to North America and are known for their vibrant purple flowers that bloom in late summer and fall. They are a favorite among gardeners for their ability to attract pollinators such as bees and butterflies. In the right conditions, they can create a stunning display of color in your garden.
However, their aggressive growth habit can sometimes cause problems if left unchecked. They have a tendency to spread through self-seeding, and their rhizomatous roots can send out runners that can quickly take over an area if not properly managed. This can lead to overcrowding and competition with other plants in the garden.
To prevent purple asters from becoming a nuisance in your garden, there are several management techniques you can employ:
1. Regular pruning: Pruning back the asters in early summer can help control their growth and prevent them from spreading too aggressively. Cut back the stems to about half their height, which will encourage bushier growth and reduce the chances of self-seeding.
2. Deadheading: Removing spent flowers before they have a chance to develop seeds can also help prevent self-seeding and keep the plants in check. Simply pinch off the faded flowers or use a pair of pruning shears to snip them off.
3. Division: If your purple asters have become overcrowded and are encroaching on other plants, consider dividing them every few years. Dig up the clumps, separate them into smaller sections, and replant them in different areas of the garden. This will not only help control their growth but also rejuvenate the plants and promote healthier growth.
4. Mulching: Applying a layer of mulch around the base of the plants can help suppress weed growth and prevent the asters from spreading through runners. Make sure to leave a small gap around the stems to allow for air circulation and prevent rot.
5. Regular maintenance: Keep an eye on your purple asters throughout the growing season and promptly remove any seedlings or runners that start to encroach on other plants. Regularly inspect the area around the asters and take action to keep them in check.
While purple asters may not be classified as invasive, it’s always important to be proactive in managing their growth to prevent any potential issues. By employing these management techniques and staying vigilant, you can enjoy the beauty of purple asters in your garden without any headaches.
