Plants and leaf litter?

Hey all!
Ok so I've scoped out some of the terrestrial and semi-aquatic tanks for FBNs and I have to say, I'm preferring the semi-aquatic set ups, even though land set ups are easier to keep clean that with water, but they are amphibious creatures with webbed feet and a finned tail, so naturally wouldn't they be more at home in semi-aquatic environment?
I also noticed that plants play a huge role in both semi-aquatic and terrestrial set ups, and I do not have any foliage except a tiny hard plastic plant, which they only run to if it's a hiding spot. Could this be a big part of my problem?
Now someone mentioned adding some leaf litter to their environment they are in at the moment, just leaf litter from like a garden or is this special stuff I buy at a pet store or gardening store?
What about if I go to a forest and grab some moss that has been growing on a log or rock? What if I collect wood or rocks with moss already on it and place them in the 30 gallon? And how about plants, can I find a pond in a woodland and snag some lily pads and such, then just re-plant them in the tank?
And I was wondering...woodlice, don't know what they look like but assume that I can also finds these in the woodlands as well...by pulling bark off trees? Now when I collect these, or even fruit flies, do I have to worry about infestation of any kind lol! To get my own fruit flies, do I just stick a small piece of fruit in the newts habitat? And how about raising my own little worms, I live in an apartment so composting isn't possible as much as I would love to. I need to find variety for these guys because so far they prefer meal worms mostly, one or two may go for a piece of cut up BIG worm, but I have witnessed at least one of them spit out a worm and go for the meal worm instead...not good as far as I know.
They are very interesting animals, I do enjoy tending to them, but they are very new to me, and unlike a dog or cat, even fish for that matter, I can't tell if they are happy lol! Thank you all for ALL the help roud:

I also have FBN (cynops pyrrhogaster) and have them in an aquatic set up which is better for them in the long run apposed to terrestrial.

My guys are still only juveniles so are not fully aquatic and I have them in 2 inches of water now with plenty of rocks and wood sticking out along with floating live plants giving them plenty of access to come out of the water should they want to and trust me still do

As for food, I personally feed my guys earthworms (chopped) whiteworms & bloodworm which works for them and me, I still do this by hand.

I would be very careful about taking anything from the wild as you dont know whats been growing on it etc and you could well harm your newts by bringing in something uninvited but I am sure someone with more newt experience can help you with this as I have no experience of terrestrial set ups !

Here is a good link to culturing flies etc from a user on here (berksmike). Culturing Instructions - Frogs and Food so hopefully this will give you some idea but I know from experience whiteworms are great and come in a very small plastic box which you top up with fish food flakes every few days so easy as and requires no space! Same can be said for an earthworm culture again they are easy to do and dont require a lot of space or time.

Best of luck!!