Helichrysum 'Silver Mist'. Window box plant. Click image to add to your lists and to get care advice. Other names: Liquorice plant  Helichrysum petiolare, Helichrysum minus 'Silver Mist',  Helichrysum petiolare minus 'Silver Mist', Plecostachys serpyllifolia 'Silver Mist', Everlasting flower. 'Silver Mist' is a tender, mound-forming to trailing, evergreen sub-shrub, often grown as an annual, with branching stems bearing oval, woolly, silvery to grey-green leaves and small, dull cream flowers