Answer: You might be able to very carefully use an herbicide containing glyphosate by wiping it on rather than spraying it. This will eventually translocate to the roots and kill the dandelions. Be very careful to read and follow all of the label instructions and allow it the full time to work. Alternatively, when it is time to refurbish the iris bed and lift and divide all the iris, you could go after the dandelions then.
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