This appears to be Powdery Mildew, a very common fungal disease that affects many plant species. (The same mildew might not be moving from one plant to the next, but rather closely-related and identical-looking mildew species can be infecting different plants simultaneously because the type of weather conditions they all thrive in are present.)

Fortunately, severe impacts on host plants are rare and you can generally ignore it. While cutting back infected growth might temporarily reduce infection severity, it also might impact flowering time and bloom abundance so we tend not to encourage it. (You can experiment and try, though, if you want.) Pruning off infected growth also won't prevent re-infection since this kind of fungal disease thrives in humid weather and could continue to infect foliage well into summer by means of windblown spores. If you feel the need to treat the plant with a fungicide, follow all label directions and be aware that fungicides, while not targeting insects per se, still could have unintended negative consequences for pollinators and other organisms, so do not spray open blooms and reconsider treatments if you're growing the plant as a host plant for butterfly larvae.

You don't need to remove the plant if you otherwise want to keep growing it; powdery mildew might not necessarily be as bad in a future year (given its weather dependence) and as the plant matures it'll have more energy reserves in its roots to draw on for any occasions where it's more severely impacted by fungal growth.

Miri