Many biomes will spawn the ferns, you can pick up a few and go with it.
You can also make a bee house, and breed a tropical drone to a forest princess. The beehouse will prevent mutations, you'll get back one or both kinds of bees you place in. It's farly easy by this means and using the beealizer to pick out the bees that have the right flower type needed to make a line of tropical bees need only normal flowers.
You can also remove their poison effect this way, something I did to my three sets of tropicals. Breeding with forest, and continue breeding with only the bees that have the right active traits until both active and inactive become the same, then only breed those to 'purify' the line and bam...
Pretty much this:
(it is far easier then it sounds)
Step 1. Mix a
Forest PRINCESS &
Tropical DRONE in a BEE
HOUSE.
Step 2: Scan all bees that come from the Queens death. Check for flower type/trait type you want.
Step 3: Look for bees that have the traits you want and keep those to breed, the rest toss aside, or use to repeat step 1 & 2. If you have to mix in more normal forest bees to keep pushing the trait you want then do so, but try and keep that to only forest/tropical mix's, and only breed back into the line the bees with the trait you desire.
Step 4. You aim for both a tropical princess and drone with the
ACTIVE trait being what you desire. This could mean breeding more then one set of bees (use the bees from step 3), like for myself I did two sets, and once you get a bee from one set with the desired trait, keep hold of it and try to gain more from the other. The hardest part is getting a princess with the trait you want, once you get one, hold onto it, and work on getting a drone with the same, then breed them together.
Step 5: Repeat until you gain a tropical drone/princess that has both active, and inactive trait to that of what you want, start using ONLY those bees.
Step 6: Repeat breeding until you get drones that stack that have the same active and inactive desires trait. By repeat breeding both the drones and princess will have the same stats, congrats you just make a 'pure' line with the desired traits you want.
My none effect tropical bees, I could have edited the flower type, or lifespan or any trait too but I was near a tropical biome anyho and don't really care about the rest of the traits as I have three of these and plenty of drones to make more if I need it.
This set took 3 generations to make, bred forest princess to tropical drone, was lucky to get a tropical princess right off that gained the trait I wanted (the none effect), then just mixed a forest/tropical from the same set that also had the desired trait, then from that got a tropical princess and drone that both had the right trait and bred them together, bam, three gens and no more posion effect. Continued breeding ended with purifying the line so the queen always gives the same stat princess and drones that stack.
Took five generations with the other, and to make the 3rd I just force fed a normal forest nothing but drones from these two until the species and all traits overwrite the forests bees stats until it was no longer a forest bee, but a 'copy' of one of these.
Yeah not worried about any of the other traits, as I already got plenty of combs.