Anyone who has planted bugleweed in the hopes of covering a difficult-to-plant spot in the landscape probably won't be surprised to learn that it has invasive tendencies. After the charming purple flower spikes have faded, the plant gets busy spreading everywhere by sending out runners that rival mint in peskiness. Soon, the clump you planted beside your hosta collection is running right up the crowns of those hostas and everywhere else, taking up all of the water and nutrients and turning your garden into a monoculture. A lovely and well-behaved alternative is lungwort, which spreads slowly but not invasively in moist spots.