Hi Susan,

Thank you for reaching out to us at the UNH Extension Infoline.

I am sorry to hear that your Asters are taking over the garden! Are these New England Asters (Native)? If so, they can definitely get a bit aggressive if you have more than one plant. It can spread vegetatively and by seed. 

I will be including a few resources for you to reference below for control methods, a few will be referring to invasive plants (which aster is not listed as invasive) - but I am hoping a few of the methods might still apply with the aggressive growth habit.

Resources:
1. https://www.backyardecology.net/new-england-aster-a-beautiful-and-diverse-native-wildflower/#:~:text=New%20England%20aster%20can%20be%20kind%20of,over%20if%20paired%20with%20equally%20aggressive%20plants.
2. https://extension.unh.edu/resource/invasive-plants-specific-methods-control
3. https://extension.illinois.edu/blogs/know-how-know-more/2017-07-25-garden-gone-awry-how-control-aggressive-garden-plants

I hope that this information helps. Please reach out if you have any further questions!

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