Here is a picture of my river birch. Here is a link that might be useful:

Hi transplant, I think you may be confusing mulch and compost. Mulch is a substance, organic or inorganic, that lies on top of the soil and whose main purposes are to regulate the soil temp, preserve moisture and help prevent weed growth. In your case, the rocks are your mulch. As far as feeding your plants, I'm just going to speak in broad generalizations here. Many xeriscape plants don't like rich soils or a lot of fertilizer; however a light feeding of most of them once a year is usually a good thing. Don't use a fertilizer high in nitrogen at this time of the year - nitrogen stimulates green growth. I use a liquid, organic formula that can be either sprayed on foliage or poured onto the soil. This works well for rock mulched beds. Again, this is just a generalization and you might want to do some research about the individual needs of your plants. Hope this helps.

I hadn't heard anything about it until I saw this thread. Gosh, the poor thing. No friends, no family, and cold to boot! They need to move it back to Florida, but I sure wish I could see it first. I must have been a skeptic since birth because when I was a little kid I thought manatees were just "another dinosaur hoax." I'm a little smarter now. I think they are fascinating critters.

I'd just flush it thoroughly by pouring a volume of water = to the container volume through it 5-10 times. That should do the trick. I wouldn't plant in it w/o flushing it. Al