Answer: Honeysuckle flowers on new growth so hard pruning is the answer to both keeping the plant under control and encouraging lots of new flowers. I tend to cut mine back by about one half and then reach in and cut some of the vines down nearly to ground level. This way I have a good sized vine with lots of new growth and lots of flowers every year. Early spring is the best time to prune.
Spirea can be sheared, which keeps them dense and full of flowers. You can thin it out if you wish, but what you're doing is perfectly okay. Spirea blooms on new wood which is why yours is blooming on the outside and not on the inside. If you want flowers on the inside, you'll need to promote new growth by cutting some of the oldest stems down so they can regenerate. The choice is yours.
Yews do not need pruning unless you want to turn them into a specific shape or make them a hedge. Otherwise, you don't need to prune.
As for fertilizing, it's only necessary if your shrubs are not growing well or the color is poor. If they're growing well and look good, it isn't necessary to fertilize.
Enjoy your garden!
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