Mustard Willow
The Mustard Willow is a plant that can be found near bedrock oil deposits. Its leaves can be harvested and processed into 
cadmium, which is mainly useful for making 
cadmium steel. There's a in-game guide on how to grow and harvest the mustard willow, It can be viewed by hovering over the plant item and pressing LSHIFT+F1.
Growth
The mustard willow will only successfully mature under these conditions:
- Water is adjacent to the block below the plant, otherwise the plant won't grow at all, or accept bonemeal.
- It needs to be placed on top of dead or oily dirt to fully mature. It can still grow on top of normal dirt, but it won't drop any leaves when harvested.
- It doesn't require any light to grow.
The mustard willow has 5 stages of growth. At the second stage of growth, it needs a extra block of space above it to continue growing. At the fourth stage of growth, it needs dead or oily dirt underneath it to fully mature, consuming it in the process. Replacing the polluted dirt can be done manually after harvesting the plant, or automatically by running a fracking tower that continuously pollutes the earth, keeping the mustard willow intact.
Finally, when it's fully red and matured, the top part of the plant can be broken to get 3 to 6 mustard willow leaves, and a mustard willow plant. The plant can also be harvested with an automatic buzz saw, meaning the entire lifecycle of the plant can be fully automated.
Uses
The leaves can be acidized with 
high-performance solvent.
 250mB 10 
|
The main plant can be liquifacted into 
ethanol.
     50mB |
Trivia
- Though "mustard willow" does not refer to any real-life plant species, some plants from the genera Salix (willows) and Populus (poplar) have been found to absorb cadmium from the soil.