Good old fashioned busy Lizzie is hard to find nowadays, if it can be found at all. The nasty mildew that kills it so quickly might not be prevalent everywhere, but happens to be a serious problem where most of the bedding plant farms are located. Now, the formerly uncommon New Guinea impatiens, Impatiens X hawkeri, which is somehow resistant to the mildew, is becoming popular.
The two specie have distinct personalities though. Busy Lizzie dazzles with cheery cartoonish colors, and bloom profuse enough to almost obscure the light green foliage. New Guinea impatiens has bigger and bolder flowers of white, pink, red, magenta, lavender, purple, apricot and reddish orange, but does not try to hide its rich green, bronze, purplish bronze or gold variegated foliage.
New Guinea impatiens are more expensive, and are not available in cell packs like most other bedding plants are. They are most popular in four inch pots. They do well in pots and tolerate partial shade, but want rich soil and regular watering. Mature plants can get more than a foot wide, and might get as tall if crowded. Although grown as annuals, they can survive as short term perennials.
In only a few years, busy Lizzie, Impatiens walleriana, went from being one of the most popular warm season annuals to being unavailable in nurseries. It is now making a slight comeback. Most of those planted during their planting season last spring are now so profuse with bloom that their rich foliage is mostly obscured. Although they can be perennial, almost all get replaced in autumn.