appearances arid barrel barrel-cactus Cacti cactus clumps clusters coloring colors colouring colours display edge edges flora frilled frills garden-display garden-plants green irregular leaves light ornamental perennials plants pointed protection ribbed ribbing ribs round shape shapes sharp short-spikes small-spines spikes spines spiny succulents sunlight surface surfaces tall textures unusual variety abundance ageratum annuals appearance bedding bloom bloomimg blooms blue-billy-goat-weed blue-billygoat-weed borders chick-weed color colored colorful colour coloured colourful containers cultivars cultivated edging exotic florets floss floss-flower flower flowers fluffy fuzzy goatweed greenery hardy leafy potting-plants profusion purple rock-gardens soft weed wild attract-prey attracted attraction carnivore carnivorous carnivorous-plants cover devour digest digested digesting distinctive enzymes funnel herbaceous insect-trap insects nectar-like-secretions nutrient-source nutrients operculum passive-trap pitcher-plants pitchers pitfall-traps prey proteases rims slippery species trap variations vegetation veins