They sort of did, but it wasn't always necessary.

National botanic gardens (like the one in Kew) had this as part of their remit, as did more local research stations in the tropical world. And in fact some plant transfers were successfully made, as Lucille Brockway pointed out in 1979, and the more recent edited volume Colonial Botany: Science, Commerce, and Politics in the Early Modern World may have something of interest; Richard Grove has written a ton on the gardens too. It wasn't simply a matter of having the right temperatures and rainfall--there were many other variables that affected viability and (importantly) yield, from soil pH and nutrient content, to compatibility with the transplant ecology, which were all weakly understood until recently. The botanical stations and gardens had the aim to understand how these things grew and see if they could be scaled up or done elsewhere; sometimes they were wildly successful to the point that we don't even think about it now (like rubber or cocoa). But honestly, spice and commodity crop planting in a colonial environment was best once imperial possession of land was taken, and some short-distance transfers were in fact done in ancitipation of this--certain teas to Sri Lanka and India, in particular (see Webb's Tropical Pioneers on that), coffee strains into various places, and so forth.

In other cases, it was actually only with actual espionage that cultivars could be smuggled out of the point of origin--spice merchants/growers, whether European planters or non-Europeans, protected their valuable knowledge and plants as you might expect. Then one had to keep it alive for the entire course of transport, get enough to grow in a controlled environment (such as the scientific stations), and successfully introduce it elsewhere and make it commercially viable. That's a lot of investment in capital and time, but it was attempted from time to time, for example with cloves and cinnamon in the Caribbean, which the Royal Society for the Encouragement of Arts, Manufactures and Commerce offered a prize for in the 1820s. Cinnamon has in fact become a viable crop in parts of Latin America. Still, yields were usually inferior in terms of value to those shipped in from Asia, and less reliable than more locally established crops in terms of bringing revenue to planters.