appearance bell-shaped biennials blooming blooms clump-forming colored colorful colors coloured colourful colours cultivars decorative Digitalis display distinctive downward-facing erect exotics flora floral flower-spikes flowers foxglove garden garden-flowers garden-plants herbaceous horticultural horticulture light mottled nature ornamental perennials petals plants potent-glycosides shape shaped shapes tall-spikes textures toxic toxicity tubular unusual whorls black brightly-coloured carpeting-plants clumps common daisy-like drought-tolerant environmental-weed flower garden flowers garden-escape gazania gazanias golden hardy introduced-species invasive lance-shaped leaves low-growing orange perennial prolific rapid-spreader resilient roadside-weeds South-African streaked tough vivid water-wise weed widespread wind-blown seeds yellow brightly coloured carpeting plants environmental weed garden escape introduced species rapid spreader roadside weeds South African brown color coloration colour contrast contrasting wind-blown-seeds winter lance-shaped-leaves