How many ponies are under the hood?

Itʼs burninʼ hot as iffen the house was caught on fire.

Without the wall a birch-tree shows / Its drouped and tasselled head; / Within, a stag-horned sumack grows, / Fern-leafed, with spikes of red.

Their feet steady, their hands diligent, their eyes watchful, and their hearts resolute.