Hi Barbara,

Thank you for reaching out to Ask extension with your question! We also received your inquiry directly to our office distribution email, which had a bit more information in it which I will copy and paste here:

Greetings:

I have a Cone Tree that planted itself in my yard. I live by Dry Creek in Centennial. I would like to poison the tree to get rid of it and the suckers which try to take over everything. I have used Sucker Punch on the suckers to no avail. I would like to know if I can legally poison the tree and if so what do I use and how do I do it?

Thank you for any help you can give me.

Barbara P

Would you have the ability to send over a photo of your cone tree, so we can see what type of tree you have? You should have an option to upload photos in this Ask Extension platform. Without a picture, I am only assuming you have an evergreen type of tree (like a Pine, Spruce or Fir) since you mention a tree with cones, and that what you are dealing with is not a deciduous tree, is that correct? 

I'm also wondering if there is a parent tree these suckers are growing from? True "suckers" grow from the roots of plants, and if you wish to use something to kill off the suckers, then you will likely damage or even kill the parent tree also. On the other hand, some trees send out seeds that can then germinate and become a weedy nuisance in yards, like Elm tree seeds that blow everywhere and then produce small Elm trees that sprout up all season. 

I guess what I am getting at is: are these true suckers, or are they seedlings? Seedlings would be easier to get rid of than suckers. Products like the Sucker Punch that you mention are never going to kill the suckers (or even seedlings). The chemicals in these products are plant growth regulators designed to slow down and inhibit the growth of the suckers from the parent root, without killing the parent tree. 

If you would like to kill the suckers (or seedlings), along with the tree they are growing from, then using a product with Glyphosate will work. It is a non-selective and systemic herbicde, meaning it will kill anything it touches, and the chemical will move systemically through the plant to kill the root and all parts. Many products contain Glyphosate, so there are many choices, but you must read the label on your product and apply the herbicide acording to the label, as the label is the law.

I hope this helps!

Dawn