Nikolai Mavrenkov already created a good description of the problem on Stack Overflow: http://stackoverflow.com/questions/36893449/textarea-placeholder-isnt-shown-in-ie-11-being-rendered-using-react

I just can confirm it breaks in IE11, but works in IE10 (and other browsers) with React v15.0.2.

var el;
      if (namespaceURI === DOMNamespaces.html) {
        if (this._tag === 'script') {
          
          
          var div = ownerDocument.createElement('div');
          div.innerHTML = `<${type}></${type}>`;
          el = div.removeChild(div.firstChild);
        } else if (props.is) {
          el = ownerDocument.createElement(type, props.is);
        } else {
          
          
          
          el = ownerDocument.createElement(type);
        }
      } else {
        el = ownerDocument.createElementNS(
          namespaceURI,
          type
        );
      }
      var isCustomComponentTag = isCustomComponent(this._tag, props);
      if (__DEV__ && isCustomComponentTag && !didWarnShadyDOM && el.shadyRoot) {
        var owner = this._currentElement._owner;
        var name = owner && owner.getName() || 'A component';
        warning(
          false,
          '%s is using shady DOM. Using shady DOM with React can ' +
          'cause things to break subtly.',