1.11.2 adding decorate item to vanilla biome

I've not had any luck adding a new plant to a vanilla biome and haven't found anything that worked in older versions that works for me in 1.11.2.

Here's my failed approaches:

1) Create a new biome and replace it over vanilla biome.

a) GameRegistry.addSubstitutionaliase --- Type only takes Items or Blocks --so info on that isn't helping for 1.11.2

b) using biomemanager (add mine, remove theirs)

		[in preInit]

		ImmutableList<BiomeEntry> list=BiomeManager.getBiomes(BiomeType.WARM);
		//find the biome
		BiomeEntry plains=null;
		Iterator it=list.iterator();
		while(it.hasNext()){
			BiomeEntry be=(BiomeEntry)it.next();
			if(be.biome.getBiomeName().toLowerCase().equals("plains")){
				System.out.println("*******************Plains Biome Found***********");
				plains=be;
          		//be.itemWeight=0; --has no effect
          		//it.remove() -- causes Immutable modification error
          		
          //below doesn't do anything--see below on replacing BiomeDecorator
          		//BiomeDecorator bd=be.biome.createBiomeDecorator();
				//BiomeDecoratorD bd2=new BiomeDecoratorD(bd);
				//be.biome.theBiomeDecorator=bd2;
			}
		}
		
		if(plains!=null){
			System.out.println("Plains Remove");
			BiomeManager.removeBiome(BiomeType.WARM, plains);
		}

With something like this, I get both "Plains Biome Found" and "Plains Remove" printed out. However, the plains biome is still listed if I do a check just afterwards.

Set <ResourceLocation> biomes=Biome.REGISTRY.getKeys();
				
		Iterator<ResourceLocation> itR=biomes.iterator();
		while(itR.hasNext()){
			ResourceLocation test=(ResourceLocation)itR.next();
			if(test!=null){
				System.out.println("Biome in registry:"+test.getResourceDomain()+":"+test.getResourcePath());
			}
		}

And still is generated with a newly created game.

c) Trap the DecorateBiomeEvent.Decorate event and change plants there

I can successfully trap the event (say of a grass generated) and DENY it, however, if I try to create anything during this event trap, it creates another Decoration event, which spins out of control and causes a stack overflow error.

Further, trapping the BiomeEvent.CreateDecorator and trying to set the decorator here to one of my causes another Creator Event and spins out of control, causing a stack overflow.

BiomeDecoratorD biome_decorator=new BiomeDecoratorD(event.getNewBiomeDecorator());
	event.setNewBiomeDecorator(biome_decorator);

d) replace the biomeDecorator

I can find the biomeplains (above) and try setting theBiomeDecorator =new myBiomeDecorator(); //no errors, but mine is never ran.

See above in preInit where I try to set the replacement

@Override
	public void decorate(World par1World, Random par2Random, Biome biome,
			BlockPos pos) {
		System.out.println("BiomeDecoratorD:decorate***************");	//never called
		//super.decorate(par1World, par2Random, biome, pos);	//normal biome is still generated
	}

So, if anyone knows how to do this in 1.11.2, please point me in the right direction---first which approach, a sample line or two would be helpful as well if you can take the time.