Ester based 2-4D will break down quicker if you can find it.
Which brands of
liquid-ester 2,4-D are labeled for aquatic use? Also, why would an ester 2,4-D break down more rapidly?
Navigate will also kill it but its kinda pricey. Its just a granular form of 2-4D.
NAVIGATE is a
granular butoxyethyl
ester 2,4-D, and is labeled for aquatic-use. But, it would likely prove lethal on nearby lilies as well.
Low-velocity/no-drift topical spot-treatments with imazapyr work well on primrose, and are unlikely to have much (if any) impact on adjacent/untreated emergent plants.
