A new and distinct Torenia plant named `Danmoon15` particularly characterized by plenty of delicate, funnel form, cup-shaped flowers with petals in shades of violet and purple-violet with a yellow blotch on lower petal; cascading bush, which maintains a compact, rounded plant habit; vigorous growth habit; densely branched plant, gracefully cascading from hanging baskets; early flowering response and stays in full bloom in moderate climate; suitable as an annual for hanging pots outdoors under partial shade; and good weather tolerance with a preferred temperature range of 15.degree. C. to 25.degree. C.