We inherited a mass of overgrown forsythia when we moved in five years ago. We've been pruning them for the last few years, and they're finally starting to take shape.
Technically, they are not on our property, but they cover a large part of the border between us and our neighbor, whose yard is otherwise meticulous. We've made it our business to improve the view, and we're pretty satisfied with the progress.
The trick was to cut back a third of the tallest branches all the way to the ground each year. This stimulates new growth, so we get blooms from the ground up, rather than just a few at the tips. We also removed a lot of dead branches, those that were crossing over each other, and those that were hanging too close to the ground. If given the chance, they'll reroot, and then it's a bigger mess.
I've just discovered a couple of other random patches of neglected forsythia, and hope to do the same with these.
I find it's easiest to prune them when they're in bloom (because they're easy to identify), though it makes the most sense to do it after the flowers fade so that you can enjoy them first. I took some of the branches I cut inside and put them in a vase so it wasn't a complete loss.
While I was pruning, I took care of the hydrangeas, removing last year's spent flowers, cutting down to the next bud on the branch. I also removed any branches that didn't have any buds on them. One of the few things I retained from the hydrangea expert I met last year is that March is when it's best to remove a little more if you want to shape the plant. Since ours are relatively young, I only removed the minimum to keep them healthy.
My hydrangea pups- those that I tried to propagate last year- don't seem to have survived the overwintering in the shed. Not enough light? I'll make some more early this year, and plant them late summer/early fall. I seemed to have better success that way.
This weekend, I'm going to split our catmint to put half beneath our climbing hydrangea,
and move the periwinkle to a more prominent spot so that next year it'll bloom near the crocuses and daffodils.