Roses and sawflies

This is the second year that my English roses have been in the ground. I’ve found that some of them definitely need support because the flower heads are so big, particularly for deep red Munstead Wood, yellow Golden Celebration, and peachy-orange Jude the Obscure. On the other hand, their floppy nature gives a natural, blousy look to an arrangement when their stems are draped over the edge of a vase. I’m loving the scent of Jude the Obscure, which smells of spices and fruit, and two of my overall favourites are the fluffy, delicately pale pink-white Desdemona and light-pink climber The Generous Gardener.

One day while out in the rose garden, I spotted some large flies, with unmissable bright yellow abdomens, sitting on some of the rose stems. They turned out to be rose sawflies, the larvae of which can very quickly defoliate large portions of a rose. Indeed, these initially tiny caterpillar-like larvae stripped a number of rose branches in my garden last year before I realised what was happening. After a bit of online research, I learned that sawflies lay their eggs inside young, tender rose shoots. This causes the stem to swell and split, exposing the eggs inside (NatureSpot has some good photos of the adult flies and an egg scar).

I had a look around my roses and found that these scars were quite easy to spot, once I knew what to look for. Instead of waiting to pick off munching larvae after the eggs hatch, I decided to proactively control the roses’ pest burden by pruning out the shoots where eggs had been laid (luckily there were only a handful of affected shoots). The pruning was unfortunate, although it did remove the damage made by the egg scar, and the roses will make a new shoots, but more importantly, it’s one way to control garden pests without resorting to chemical pesticides.