The Wood Effect, whereby foliage shows up 'white' in infrared photographs, is a well-known feature of such images, often mistaken for snow.
Leaves are not the only things to exhibit this, as I found once when photographing young pine cones.

I presume that the young pine cones have an outer layer like a leaf with cells that reflect the infrared light, but this was a bit unexpected.
This next photo shows some seaweed (on the coast of Bardsey Island in North Wales) and this also exhibits the effect.

The black dots in the water are seals by the way.
A final thing that looks different to what you would expect in infrared photography is red wine, which appears transparent. A photo to demonstrate that is for another post sometime. Cheers.