This is really completely Mr. Bromeliad's DIY. My sole contribution was measuring and marking some wood.
The highly resourceful Mr. Bromeliad set off for Home Depot one Saturday morning when he came across a deck being torn out. He picked up the discarded treated wood and never went to Home Depot.
Below you see the rustic conditions under which an urban DIYer must work. Mr. B used a hand saw for his cuts, a paintbucket as as table and his lap as a sawhorse. (A friend with power tools did the top piece for us as shown above. It was impossible to cut the angles with a hand saw, not for lack of trying.)
Now both of our big shrubs are snug for the winter.
Are you still enjoying outdoor spaces where you are?