Also called sword ferns, Kimberly queen ferns (Nephrolepis obliterate) make elegant specimen plants, thanks to their straight, upright fronds. These nearly-carefree Australian natives are happy indoors if they’re kept in medium light and given sufficient humidity (if your air is too dry, try running a small humidifier nearby). Outside, they’re hardy in zones 9-11. Indoor gardeners love them because they help purify the air, but you can also enjoy them outdoors in warm weather months.