| I'll take a stab at noting that most plants designated as "houseplants" are those that can grow and/or thrive in a household environment, which is generally warm, dry, and not very luminous year round. Plants that developed in that environment tend to be tropical evergreen understory plants that may not go dormant... or if they do, they do so based on a "wet" and "dry" season or based on day length. The one plant that I see commonly sold as a houseplant that can grow outside in temperate climates is English ivy. There are a number of cultivars, particularly the minature or "needlepoint" and minature variegated forms and even those can be grown outside in moderate to warm temperate areas (with protection in colder spots). There are some cold hardy gardenias that could, once established, do well in the warmer temperate areas if protected, but can also be grown inside as a "houseplant". Another temperate that can be potted and possibly grown indoors is Passiflora incarnata ("maypop"), as I know from my experience with both the temperate and tropical passies that I have, they can do fine inside in winter in a container, with some eye on controlling their normal rampant growth. If sufficient light is given to them inside, they will even bloom (my Passiflora belotti does). Also, there are many sedums, temperate agaves, and even temperate cactii that will grow outside year round in temperate climates and can be successfully grown indoors under household environments. The native prickly pear cactus (eg., Opuntia humifusa, etc) is one that comes to mind and the popular "Hens and Chicks" is another. Don't know of a specific website that discusses origins of common houseplants, but you might be able to go to the Houseplants Forum to see if anyone there knows of one. |
