We replaced the overgrown Picea pungens 'Glauca Globosa' with Picea pungens 'Glauca Globosa Nana'. It supposed to have half the growth rate of Picea pungens 'Glauca Globosa'. If that is true it will overgrow its spot in the garden in 28 years rather than 14 years. I hope I am around to see the next replacement.
Our Viburnum sargentii 'Onondaga' had all the bark girdled by mice 360 degrees around this year and was also replaced. Maude found a wonderful, and very heavy, specimen. No one will ever know what happened; all in a days work for public gardeners.