Leatherleaf Mahonia is considered invasive, but I was delighted to find this one blooming in the woods near the driveway. Looking around, there are several more-birds love to eat the dark purple berries and have distributed the seeds nearby. The berries are tartly edible and rich in vitamin c. The holly-like leaves pop of green and delicate, creamy yellow flowers are welcome in my winter woods.
Update Dec. 2016–Dave’s Garden website talks in detail about the pros and cons of using Mahonia in your landscape. The ones I discussed a few years were already here on my land, and I certainly don’t want to encourage planting invasive, non-native species in your landscape, but this one seems to be acceptable in some situations. It also seems to be a useful plant to some bird and insect species, so it does have some redeeming qualities.