Just be aware, thsi stuff shrinks, a lot. I am fairly certain there is a better product out there, but, this works well enough. you just have to do multiple, thin pours.
I'd not bother color matching, I'd add some boggy terrain bits to the bottom area. My house is situated at the top of a rise above a small wetland and this is pretty much looking like my back yard. The closer to the wetland the grass gets the darker it gets. Do some patched of tall grass and cat tails, maybe pour some pools of water effects here and there as well. Should sell the effect.
Thank you! I bought the heart from this shop: https://www.etsy.com/shop/MsReingardMiniatures
then mixed red and a little bit of brown into this medium: Woodland Scenics Realistic Water
Here are the amazon links to the products, which you can find in almost any hobby-shop that sells model trains and the like:
Realistic Water: http://www.amazon.com/Realistic-Water-16-fl-oz/dp/B000A7PPOE/ref=sr_1_1?ie=UTF8&qid=1439523433&sr=8-1&keywords=realistic+water