[Tilted Irish Kilt]

oldvirginian :" I have some out of control boxwoods in the front yard of the place I rent.
The haven’t been trimmed in the last 15 years and are now
approximately 8 feet in diameter and approximately 4 1/2 feet tall.
Anyone know the best/easiest way of rehabbing the yard monsters?
Any help/advice is appreciated."

The ideal/best time to trim shrubs and or trees is when they are dormant (ie.: early spring, or late fall).
If that's not practical, you trim when you can, and the weather is agreeable.
When you do trim, remove no more than 1/3 the foliage at any one time, or you will 'shock' the plant.
It sounds counter-intuitive for taming 'wilding plants', but you might consider topping off the top of the plant to open it up to sunshine,
and then applying a foliar fertilizer, like Miracle Grow, to stimulate interior growth to fill out the plant .
It is best to tame the plants in graduated steps, rather than to just do a 'hatchet job', or a "one-and-done'.

[oldvirginian]

Thanks for the information on the boxwoods. I had wanted to get rid of them since they are along a sidewalk that no one uses and a PITA to mow around, but the new owners wife wants to keep them so I’ll try to make them pretty again.

I’ll top them out and apply Miracle Grow this year then worry about trimming the sides back next spring.

Once again, thank you.