I’ve been working on restoring the shape to a yew hedge this week so thought it would be a good opportunity to show the importance of cutting out vertical growth. This technique applies to restoring both yew hedges and yew topiary.
If a yew has been left untrimmed, or has been badly clipped in the past, then thick, long stems can start to grow up on the outside of the hedge. These will thicken over time, causing the hedge to bulge and sag. Ignoring these stems and running the hedge trimmer or shears up over this vertical growth can create the appearance not dissimilar to varicose veins growing up the outside of the hedge.
Ideally a yew should have short green, lateral growth on the outside and the thicker stems are all hidden from view inside, acting as the framework for the hedge. This soft, green outer growth responds well to regular clipping, creating the dense tight finish and sharp lines that yew hedges and topiary are well known for.
To remove the thick vertical stem, cut just above a point where there is young growth sprouting from the stem. This point should be set back slightly from the outer surface of the hedge. It may leave a hole in the hedge but don’t be too concerned. This will soon fill in as the young, horizontal growth thickens after regular trimming.
A yew hedge that is regularly clipped with a hedge trimmer may still have some vertical growth. Again it is good to remove these small, part-cut stems before they become a problem.
After cutting the yew hedge with the trimmers, go back and remove any small stems that are starting to grow vertically. Snip them off with sharp secateurs at a point that is set back slightly from the outside surface of the hedge.
Can take a bit of time snipping back the verticals but it’s worth it to promote the soft lateral growth. As the hedge matures, this process of removing vertical growth from the outside will become less necessary- as long as the yew is regularly trimmed at least once a year.