 Other common herbs of the poor soils of bogs include false mayflower ("Maianthemum trifolium"), and some orchids, particularly, bog candles ("Platanthera dilatata").The most common trees that invade bogs as they fill in are black spruce ("Picea mariana"), northern white cedar ("Thuja occidentalis"), larch ("Larix laricina") and black ash ("Fraxinus nigra").Swamps are typically characterized by hydric soils and have more of a canopy than bogs.