Answer: What you've read is true. Baptisia develops a deep tap root and does not like to be disturbed once it is established. Knowing this, your best route would be to deeply water the plant the day prior to the move so the soil is moist (and not as likely to fall apart). Then dig with a shovel, as deeply as possible, all around the plant. The plan is to remove the entire plant along with the entire rootmass with as little disturbance as possible.
As for the wire grass, digging is the best way to control it, or spray with Grass Be Gone or Over the Top--they contain fluazifop, which will kill grass but not your other plants (be careful if you have ornamental grass--it will kill this too).
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