Undead Plants

Plants, like anything alive, can be made undead. Contrary to what Classic: UndeadClassic: Undead pg 92 states most undead plants would less of a nuisance then their living counterparts for the very simple reason that to spread they must grow which being undead they can't....unless they are vampiric in nature. 
More over they will have all the organisms that eat the dead plant all over it. This does mean that undead crops are totally uneatable and likely dangerous to even try to consume.
Logically any dead plant material can be zombified so haunted houses could be nothing but zombified wooden buildings.
One thing Classic: Undead forgets is all fossil fuels are the remains of long dead plants and therefor potentially subject to zombification. But just what would the properties of such zombified fossil fuels be?
==References==
Category:Undead
Category:Setting Concepts