Semi-aquatic vivarium bonsai project
 

Hi all,
I am starting a project that's going to take me ages to finish and am planning to periodically post updates.
The first time I saw an orchid terrarium (at Seattle Orchids) I knew it was a project I wanted to copy! But I want to also include bonsai to mount the orchids to and make it REALLY look natural. Most bonsai would not tolerate moist orchid conditions so I started to look for a tree suitable to the warm to cold micro orchids and came up with the red mangrove, which can be grown in freshwater.
Eventually little crocodile skinks are going to live in this enclosure.
I have an 18x18x24 semi aquatic terrarium on order, 15 mangrove seedlings sitting in water (I plan to make a 'forest' of maybe 5) and I am working on the backdrop.
For the background, I really want to give the feel of a little cove at the bottom of a cliff so I did a bunch of Google image searches and noticed that the bottom for cliffs tend to get eroded by water, so I am using wire mesh to bulk out the background and make it look eroded and curved.
I am using a cork background because it is in the rightsize and I know I can grow moss on any uncovered bits. So imagine moss anywhere you don't see slate. (I bought and broke up a slate tile to use as my cliff).
I still need to fix the mesh to the bark, I think I will use pins to do that, and then I have a question: is silicone safe to use as an adhesive for the slate?
I am also thinking that I will get a sheet of hygrolon to use as a base for growing my moss.
Next question: is there a good reason not to use moss from right around my house? I live in Seattle so we have lots ^^

Allow me to give you the benefit of my experience with riparian bonsai. Mangroves are full of potential, but having them reach it requires large amounts of light and a relatively long period of time. A much quicker growing species totally suitable for situations in which its roots grow into water is the common Ficus benjamina. I grew one in a 36 x 36 x 27 paludarium in 4" of long fibered sphagnum suspended on light grid over 8" of water under 4 39W T5HO tubes. In a bit over a year, it grew from an 8" sapling to a bushy tree going out the open top of the enclosure and over a foot wide. It had over 4' of root system under water constantly. Here's a pic of a small twig grown out for about a year:

I love this project, can't wait to see this on the pictures!

Thanks! Bonsai people were telling me it couldn't be done with ficus when I was researching trees. I think I am going to give the red mangrove a try, but it's very good to know that there is a (fast) backup in case things go south! It's true that I'm not experienced with bonsai and I have read that red mangroves can have bad reactions to cutting. So I am doing a lot of research, but I think I can still use bonsai branch development techniques by letting them develop strong roots?
They are really slow growing so should give me plenty of time to keep them within the terrarium- like 5 or 6 years before they even reach the top I think with pruning and lots of light.
Sorry last night it was giving me an error when I was trying to attach photos, and I am still getting that error (security token missing) I am a little confused because I have posted photos before.