There are only a few Neomarica breeders in Europe. And it is almost impossible to obtain plants from Brazil. Since several pharmaceutical groups had started to exploit systematically the resources of the rain forest there, Brazil protects its "green gold". An export permission for living plants is extremely difficult to get.
There are some gardening companies in the USA and Taiwan, who offer plants under the names of N. caerulea, N. longifolia or N. gracilis. Apart from the long postal way, the (german) import rules have to be taken into account.
it is not allowed to import plants in soil; bare roots or anorganic substrates are o.k.
3 plants of one species are allowed, more than 3 are classified as commercial and then a health certificate is demanded.
Seeds of some Neomarica species are avaiable, also from Brazil. As it is with all tropical plants, Neomaricas can be sowed the whole year through. The quota of success depends on the freshness of the seeds and a little bit of luck. Here are some tips from my own practice:
Ich take some small dessert potties and make two holes in the bottom with a knitting needle which I heated before in a candle flame.
The potties are filled with an equal mix of cultivation soil and grinded lava, the mix sterilized in the microwave. Put in each potty one seed, which is overnight soaked in tepid water. Do not stratify the seeds. If you know to handle giberellic acid, it's fine. But in many countries you need a chemistry certificate to purchase giberellic acid. More than one seed in a potty would give problems when pricking out the seedlings.
First I had the potties with the seeds in a mini-greenhouse, together with other seeds, but if one of them has a pest (thrips or fungus gnats which are sometimes imported with the seeds) all will get it. Now I've obtained some transparent pails each of them for four potties. Place the potties on the cover and put the pail as a kind of hood over them. That way, for every 4 potties there's a "mini-greenhouse". The pails come f. i. from pudding or potatoe salad. In sowing times my family's diet is determined by the need of special vessels
The achievements are varying. As it should be done with so many 'exotic' plants: Save up the potties with the seeds for at least two years.
And if then 10 % of the seeds grow to a plant, then it is a good success for gathered seeds from wild tropical plants.
Wish you good luck!