Ranunculus repens - Creeping Buttercup. Method of removal, as for any unwanted plants, is to pull or dig them out. Notice it is growing in an area where the grass is sparse. Weeds such as this take advantage of clear soil so, improve the grass cover and the weeds will decline. The little plant top right looks like Cardamine hirsutum, another common weed and one which spreads fast by seed.

Best I can tell from the photo is chickweed and POA Annua. The chickweed is pretty easy. A little Ortho Clover, Chickweed and Oxalis killer should take care of that. The POA Annua is going to be a problem. A few treatments of Tenacity should do it but the seeds it is dropping right now are going to give you trouble for several years. A good pre m plan and careful use of Tenacity should keep it under control.

It doesn't smell like celery - the closest scent that I can think of is a bit like chrysanthemum blossoms. I don't have a photo, but there is heuchera under the roses, basil was near, and also some columbine in the same bed. Christopher CNC, I just searched feverfew, and I do believe you are right! I suppose a bird or some other critter dropped a seed there (but who knows from where). Thanks!

It would have had flowers at the top if it had lived longer. So lets call it Lactuca serriola, aka Prickly Lettuce.