Hello Charlotte,
I've got an error:

XML error: Duplicate XML node name harvestedThingDef in this XML block: <plant><harvestedThingDef>RawNettle</harvestedThingDef><harvestYield>30</harvestYield><growDays>7</growDays><harvestedThingDef>RawHealroot</harvestedThingDef></plant>

Root node: <ThingDef ParentName="WGWildBase"><defName>Plant_HealrootWild</defName><label>wild nettle</label><description>Urtica is a genus of flowering plants in the family Urticaceae. Many species have stinging hairs and may be called nettle.</description><graphicData><texPath>Things/Plant/NettlePlant</texPath><graphicClass>Graphic_Random</graphicClass></graphicData><plant><harvestedThingDef>RawNettle</harvestedThingDef><harvestYield>30</harvestYield><growDays>7</growDays><harvestedThingDef>RawHealroot</harvestedThingDef></plant></ThingDef>
Verse.Log:Error(String, Boolean)
Verse.XmlInheritance:CheckForDuplicateNodes(XmlNode, XmlNode)
Verse.XmlInheritance:CheckForDuplicateNodes(XmlNode, XmlNode)
Verse.XmlInheritance:ResolveXmlNodeFor(XmlInheritanceNode)
Verse.XmlInheritance:ResolveXmlNodesRecursively(XmlInheritanceNode)
Verse.XmlInheritance:ResolveXmlNodesRecursively(XmlInheritanceNode)
Verse.XmlInheritance:ResolveXmlNodesRecursively(XmlInheritanceNode)
Verse.XmlInheritance:ResolveXmlNodes()
Verse.XmlInheritance:Resolve()
Verse.LoadedModManager:ParseAndProcessXML(XmlDocument, Dictionary`2)
Verse.LoadedModManager:LoadAllActiveMods()
Verse.PlayDataLoader:DoPlayLoad()
Verse.PlayDataLoader:LoadAllPlayData(Boolean)
Verse.<>c:<Start>b__6_1()
Verse.LongEventHandler:RunEventFromAnotherThread(Action)
Verse.<>c:<UpdateCurrentAsynchronousEvent>b__27_0()
System.Threading.ThreadHelper:ThreadStart_Context(Object)
System.Threading.ExecutionContext:RunInternal(ExecutionContext, ContextCallback, Object, Boolean)
System.Threading.ExecutionContext:Run(ExecutionContext, ContextCallback, Object, Boolean)
System.Threading.ExecutionContext:Run(ExecutionContext, ContextCallback, Object)
System.Threading.ThreadHelper:ThreadStart()

Thank you for your mod.