alien appearance black-flag black-flag-iris blooms bright budding buds bush bush-plant colored colorful coloring colors coloured colourful colouring colours display displayed ferraria-crispa ferraria-undulata flora flowers foliage garden-escape greenery introduced-species invasive iris-family leaves malodorous-cormous-perennial mixed nature nectar pest plants shape shapes Sizes spring strange unusual unusual-shapes weed Western-Australia