organic material into usable humus. To avoid the delay presented by this process, adding manure in the fall is advisable. Some gardeners who live in areas with large amounts of red clay soil use raised beds or Hügelkultur to avoid having to amend the soil. By using raised beds, gardeners avoid having to deal with Ultisols altogether. Best plants for Ultisol When choosing what to plant in Ultisol, plants found native to regions with high amounts of Ultisol are able to thrive. Generally these are species adapted to poorly drained, damp soils. The Missouri Botanical Garden recommends tickweed, spotted jewelweed, mealycup sage, Camassia, spring starflower, ostrich fern, sideoats grama, Bouteloua curtipendula, and prairie dropseed. Suborders Aquults: Ultisols with a water table at or near the surface for much of the year Humults: well-drained Ultisols that have high organic matter content Udults: Ultisols of humid climates Ustults: Ultisols of semiarid and subhumid climates Xerults: temperate Ultisols with very dry summers and moist winters See also Pedogenesis Pedology (soil study) Soil classification Red Soil References Pedology Types of soil