pelargoniums & tropical climates - species

can pelargoniums grow in tropical climates? i received this question and am hesitant to answer as i have no direct experience with those circumstances yet i have a few suggestions...
!WARNING! the following might be a tranquillizer for anyone who is not a plant geek!

as the true species grow in places like Africa & Australia, most of them like a lot of light and can tolerate quite high temperatures. since the species can grow in very hot conditions i believe they would be the best choice for tropical climates. i also find that even though they are not as showy as the mixed, bred and cultivated pelargoniums, their flowers have more variation and are more elegant.

the main concern for all pelargoniums would be the constant humidity.the majority of species pelargoniums grow in dry and sandy or rocky regions but some come from areas with occasional heavy rain fall. these are the ones i would go for in a hot and humid home. i'm absolutely no expert on the true species but i do know that in eastern Africa, the subgroups Cicinium and Polyactium get as much as 1500 mm rain a year. still, pelargoniums dislike soggy feet no matter where they grow so it would be even more important to keep the watering down if the air humidity is high. to ensure dry feet try these tips:
- use only clay/terracotta pots.
- make sure to use a pot that is small enough, i.e. not much bigger than the root system.
- use a mixed, well draining soil. example: one quarter of something light such as perlite, one quarter of soil with lots of structure (for instance a mix with peat), one quarter of leca (2-4 mm), and one quarter of coarse sand. i buy the kind of sand used for birds as it is already sterilized.
- avoid overhead watering which can encourage fungus and disease. water in the tray and only spray mist the top soil.
- and make sure the water is needed; check to see if the soil is really dry, below the soil surface, before watering.
- provide good ventilation.

unlike the cultivars, species pelargonium can be grown from seeds. however, germination can be erratic, taking from a few days to several months so patience can be required! some suggest scalding the hard shelled seeds with boiling water, some advise to sand them lightly. the softer seeds are definitely quicker to germinate.
again, i guess that constant humidity would be the biggest problem. make sure that the containers are sterilized to disencourage fungus. i soak the pots in 1:10 chlorine and water in a bucket for a day or so before planting.
during germination, the soil should be kept moist but never wet. also, the containers should be placed in a bright spot but not in direct sunlight.
when the growth is showing, harden the tiny plants gradually with more and more direct sunlight - but start slowly.

seeds can be obtained from:
B & T
exotica
Silverhill Seeds - experts with an extensive selection.

finally, some suggestions for species pelargoniums for tropical climates:
my best bet is P. tongaense as it originates from an area with high humidity. it is very beautiful, grows easily and if you place it in partial shade it will thrive. others that like partial shade: P.crispum, P.graveolens, P.zonale, P.inquinans, P.peltatum.
for full sun try P. cucullatum or P.denticulatum.
more suggestions: P.grossularioides, P.tometosum or P.cordifolium. the lovely P.odoratissimum (a.k.a. apple geranium) likes shade and a lot of water. another scented that i think would work is P.citronellum. finally, one of my absolute favourites; P.sidoides. since it is a strong grower i think it would have a chance as well.

keep in mind that this is all ideas and suggestions, i have never tried it myself. good luck and please know that i'm very curious as to how this turns out ;-)