Garlic contains a chemical called Diallyl sulfide. It is deadly to mosquitoes in parts per billion. If you crush garlic and rub it on the undersides of your patio furniture they will avoid your next cocktail party. CA A. Yes, legumes that bloom, such as wisteria, and carnivorous plants such as cobra lily, Venus flytrap, and sundew. Blooming is nature's way of reproduction and often times, plants that are receiving adequate nutrition and growing profusely will not expend the extra energy to bloom and propagate themselves.
Carnivorous plants derive nitrogen from their prey.
Putting rocks in the bottom of the planting hole won't improve drainage, even though it sounds right. It's a lot of work to add rocks to soil. And all you get is rocky soil. If you want to improve soil's drainage, you have to improve the soil's characteristics. Instead of rocks add silt, sand, compost or organic matter.