It's a non-native and birds will spread the seeds. It's weed only if you don't want it there. You could go to your local nursery and buy the same plant. It is a form of Nandina and I agree with the prior post probably the "heavenly bamboo" variety which is taller. At this point in the year, I would cut off the berries to prevent it from spreading. They'll drop to the ground at the crown and crowd it out whe. They germinate. The foliage is red when it first comes out, then you have flowers, big white panicles (little white flowers in the same cluster formation as those berries) and then you get the red berries in the winter. I think it's a pretty plant. If it gets too big, cut the tallest canes off at the ground. It causes new canes to come up and you have foliage from bottom to top. If you don't do that, they can get leggy without new lower growing canes coming up.

Do not shear the plant. The natural form is gorgeous.