Looks like redtwig dogwood.

Is that something someone could have thrown seeds in the garden to grow or would you have to plant a tree there? The reason I'm asking is because there is no other dogwood in my yard.

Looks like a young shrub, Cornus alba 'Elegantissima'. It was probably planted there but you can never know what the squirrels might leave in your yard. :-)

Interesting information can be found at the link below.

Here is a link that might be useful: Red Twig Dogwood Shrubs