Botania r1.8-242
journeymap-1.7.10-5.1.3-unlimited

[Client thread/WARN] [journeymap/]: Error getting BlockDoublePlant icon from mod. Plese report this exception to the mod author of Botania:doubleFlower1: java.lang.NullPointerException
    at net.minecraft.block.BlockDoublePlant.func_149888_a(BlockDoublePlant.java:128)
    at journeymap.client.forge.helper.impl.ColorHelper_1_7_10.getDirectIcon(ColorHelper_1_7_10.java:197)

I get that about a dozen times total for Botania:doubleFlower1 and Botania:doubleFlower2.
I'm not sure of the implications with journey map since I haven't looked into it yet, but it may just mean that the map won't render the tall flowers, but It's only a warning so this can obviously be low priority.

Speaking from experience (colored double grass had this problem with me): BlockDoublePlant has a lot of strangeness. I'd suggest just overriding func_149888_a in BlockDoubleModFlower.java like so: (variables corrected for BlockModDoubleFlower's icons)

this is minor enough it's not worth a PR. (well... #1641)

@Override
@SideOnly(Side.CLIENT)
public IIcon func_149888_a(boolean top, int index) {
    return (ConfigHandler.altFlowerTextures ? top ? doublePlantTopIconsAlt : doublePlantBottomIconsAlt : top ? doublePlantTopIcons : doublePlantBottomIcons)[index & 7];
}