If you don't know what this is, and you see it in someone's garden, I'll bet you won't believe that it is an annual vine, an easily grown annual vine. It has the substantial look of a perennial, and that in fact is what it is in its native Mexico. But it's hard to believe that you will get so much effect from something you planted out in May. It does well under local conditions and thrives in the heat and humidity of our summers. It has no special needs in the way of soil or fertilization. It gets off to a slow start, but once it is established it grows as freely as a morning glory. So far I have not noticed any pest problems.
And the flowers are magnificent. They are about the size of a hen's egg, a large one at that. Whenever I see the flowers the first thing which comes to mind is the florists' gloxinia: the shape and size are about the same. But the two plants are not related. What Cobaea is related to will come as a surprise to most people: it's a member of the phlox family, Polemoniaceae.
For earliest bloom, I start the seeds indoors in April. The large, brown, flat, papery seeds sprout slowly, and the resulting seedlings seem to sit for a while before taking off.