In spring 1989 I inherited an elderly Forsythia, species unknown. I cut out the oldest stems at the base and over subsequent years new stems grew and matured well and I was able to remove more of the older stems, again at ground level. It has always been very vigorous, with roughly 2 feet of strong growth per stem following flowering. As it is fairly close to the path beside the greenhouse it has needed regular pruning on the left during the summer months for access, with additional pruning on the right to keep its shape symmetrical. In mid summer my regular practice was to prune the taller stems back to old wood and cut back the others about halfway. During recent years I had an increasing problem with the heavy branches on the right hand side, some of which were beginning to grow almost horizontally and vying to emulate the Leaning Tower of Pisa! My back garden is in a wind tunnel when we have northerly winds, with the old railway embankment at the bottom of the garden and the row of houses forming its sides. Obviously something had to be done about it as I did not want it to fall over and damage both itself and the surrounding plants. It is a beautiful sight in the spring and I would miss it.
Once again covered in flowers in late April 2016 and looking glorious, but far too big and by mid summer it was even taller and wider at nearly 8 feet high and 6 feet wide, again leaning badly to the right. It was time for the big chop, but as I was opening my garden in early July, I had to wait until mid July to start the job. Not the optimum time according to the books, but needs must and plants do not read the books! In mid July I cut it down to about 4 feet high and about 2½ feet wide over a period of a couple of weeks. By mid August it was putting on some good new growth and in September I trimmed a couple of inches or so off the stronger stems and removed a few dead twigs.
It came through the winter very well and in early April 2017 it actually flowered, albeit not with its normal quantity of flowers! Again I shortened the new growth during the summer in order to maintain its new look.
Despite a cold 2017-2018 winter I was rewarded with a glorious show of flowers in early April and I now have a relatively compact Forsythia, roughly 4½ feet high and 3 feet wide. I intend to remove the diagonal branch on the right hand side during the summer, as I want to discourage it from sending out any more potential “Leaning Tower of Pisa” branches! With careful maintenance I should now be able to keep it under control and still enjoy its glorious contribution to my back garden each April.
Fortunately plants do not read the rule books and with care an elderly shrub can be rejuvenated over a couple of years.