You will often read gardening advice that says “if your hedge has become overgrown and top heavy, spread the renovation over two years.”
Have you ever wondered what this actually looks like halfway through?
Well, here's one I did last year: it was a top-heavy, V-shaped hedge of Lonicera nitida, which was much, much wider at the top than at the bottom.
This is bad for several reasons: the wide top shades the narrow base, meaning that the lower leaves will die back, revealing nasty brown stems. It makes it top heavy and wobbly, so that it will tend to flap about and be damaged in windy weather. Wide tops are also prone to falling apart and splitting the hedge down the middle. And finally, it was so wide that on the inside, the Client could barely get their garage door open, and on the outside it was brushing against passing cars, which meant the neighbours kept complaining.
So, first job, cut back the section by the garage door, to the point where they can get the door open again. Check.
Second job: radical cut to one side or the other. The Client wanted the outside done first, to stop the complaints, so that's where I started.
How did I do it? I drew a mental line of where I wanted the vertical hedge edge to be: I started at one end, at the base, and used loppers to cut off any stems to the outside of my mental line. I then worked my way upwards to the top, then took a step forward and repeated the process.
When it was done, I had a huge pile of brushwood on the road, and the hedge was brown, bare, and as ugly as an ugly thing. Unfortunately I did not take a photo of it!! After a little precision work with the secateurs, I was left with a straight-edged hedge, tapering slightly inwards at the top, albeit very bare and with gaps in places. This allowed me to get right in amongst the roots, and remove all competing weeds, ivy, etc.
I then gave it a good fistful of fertiliser, a good drenching of water, and left it to recover. It quickly greened up, and once there was a good covering of new leaves, I gave it a foliar feed of seaweed, using a watering can. With hedges, I am always particularly keen on foliar feed: if you pour water at the base, some of it soaks in but a lot just runs off, but if you apply water to the top, it mimics a rain shower - the water takes a long time to run down through the matrix of leaves and branches, and arrives at the base much more gently.
As the summer progressed, the top and the inside had their usual clips, with the outside being left to grow.
Last week, the outside edge was sufficiently green and fluffy that I could run the hedge-trimmers over it. Success! It now looks perfect again, but it appears to be leaning to the right. This is an illusion - it used to “lean” equally left and right, but I have chopped off the left-hand side.
And guess what I will be doing soon? Yes, chopping off the right-hand side! By this time next year, the Client will have a slim, upright hedge which is clear of the garage door and which does not damage passing cars.
The principle holds true for Yew, for Box, even for decorative hedges such as Escallonia: firstly you cut back one side very hard, you allow it to recover for a year, then the following year you cut the other side. It takes a bit of nerve the first time you do it, and you do have to appreciate that you will be looking at bare brown stems for a month or two, but it is well worth being bold!