Flowers grown in a warehouse will be very pale. They never see the sun, so they don't grow to have bright colors.
When you grow pale flowers like this, they don't grow a soul (そう). Soul adds color to plants and flowers. That's probably why ghosts and dead bodies are pale too.
Currently there are no similar looking kanji which exist in the WaniKani learning system
Currently there are no vocabulary in our databases that utilized the kanji. Don't fret! We will have vocabulary available soon!