Hi, I planted a dog wood from a sprouted twig in my flowerbed some years ago. As you see, it is big. Part of me wants to leave it or prune somewhat as it provides incredible privacy. I thinkI should have aggressively pruned earlier as it is now rather sparse below. What would you advise: really hard prune so it will fill-in better or just crop the standard 1/3 of the bush? What would be the best approach with this plant? Thanks so much.
As all of us who garden in small spaces can attest, it can be difficult to decide on the best approach to take with shrubs that are outgrowing their living quarters. Your dogwood appears very healthy and vigorous, and it provides the privacy that you want where it is located (plus, you grew it from a twig!) so it makes sense to try a pruning approach that will provide more openness in the structure of the shrub, and a less bulky shape, while still preserving the height and width that screens your patio space.
It looks from your photograph as though you have a Siberian dogwood, Cornus stolonifera. Hard pruning is a possibility, but in your case, because you would like to preserve your privacy, you could consider using the “renewal” technique, in which one-third of the oldest stems are removed to the ground annually to keep the shrub open and provide good air circulation and light, thus promoting strong growth, disease resistance, and overall plant health. You can identify the oldest stems by their generally darker colour and their rougher bark. Older stems may be visibly in decline. Right now, in the fall, before the leaves have dropped, you could take a look at the inside of your dogwood and prune away any obviously dead or broken branches.
Here is a good article that explains pruning techniques for overgrown shrubs: https://extension.psu.edu/plants/green-industry/news/2012/hacking-whacking-dealing-with-overgrown-shrubs .
Very best of luck with your pruning activities: proceed slowly and thoughtfully. Step back and look at your results from a distance. Many gardeners are passionate about the artistry inherent in shaping their plants and observing their renewed vigour!