Solomon’s seal sawfly – yuk!


I have only myself to blame – I have been away too much recently; the majority of the garden has been neglected due to clearing space for the workshop; and recently the heat has reduced my energy and enthusiasm.  How do I know that I haven’t had my eye on the ball? Well you only have to look at the state of the Solomon’s Seal (Polygonatum) leaves above.

I had noticed something had been nibbling the leaves when I was potting up on the patio a couple of days ago.  Today when I was watering I noticed that a second plant was being nibbled and then I noticed that the first plant had been almost completely defoliated.


In the recesses of my mind I knew this was caused by the Solomon’s Seal Sawfly, obvious really given the name.  As I was watering I turned over the leaves on the lesser damaged plant and spotted a grey caterpillar, very tiny and thin, almost missable.  So I dutifully sprayed all the stems with the hose to blast the caterpillars off.  However, it occurred to me that the caterpillars would surely just crawl back.  Having put the hose away I decided to investigate further and battled to the back of the border where the first defoliated plant was.  The fact that I battled shows how out of control things are since I had planned to put a simple bark path round here last Spring; if I had done this I probably would have noticed the damage earlier.

Looking at the stems there were still some caterpillars and then I lifted a stem which was lying low and was horrified to see the mass of caterpillars below – it really turned my stomach!


What to do?  I decided to cut  both plants back to the ground and to put the stems, with caterpillars, in hot water.  Then I will bag up the stems and put them out with the rubbish rather than adding to the compost bin or adding to green waste at the recycling centre.

Research says that the sawfly lays its eggs in the base of the stems in early Spring and this causes purplish brown scars on the stems which were certainly in evidence when I was chopping everything back.  I will know what to look for next Spring and I will also think about spraying in early Spring but will have to consider this carefully since I am loath to use  chemicals in the garden.  One of the bits of advice was to encourage wildlife into the garden to eat the caterpillars.  Well my garden is swarming with wildlife: birds, frogs, aphids and still I have this infestation so I don’t know what the answer is.  If the plants are attacked as badly next year then I will think about removing the plants altogether which will be a huge pity as I love Solomon’s Seal.

So having spent half an hour going ‘yuk, yuk, yuk’ the caterpillars have been removed and there is a hole in the border. Hopefully I will have reduced the problem next year as apparently the larvae overwinter in the soil before laying their eggs next year and if I have removed the larvae, hopefully all of them, then this should break the cycle although of course there is nothing stopping more sawflies flying in.


22 Comments on “Solomon’s seal sawfly – yuk!

  1. Do you have any jays there? Here, any caterpillars that are rounded up can be left out in a box and they will disappear in an hour, snatched by the resident scrub jays.

  2. Double yuk! I understand that hot pepper water sprayed onto plants keeps the nasties away and is only chemical from the standpoint of it is food mixed with water. This might work to save your plants. I have these huge hosts which I cannot stand and I’m sure they are full of slugs – euw – next spring, before they take over my tiny itty bitty patch of yard – they are gone ………..

  3. Oh, I am so sorry for you and your Solomon’s Seal. I have two quite large stands of them and they were here when we bought this house 55 or so years ago. I never heard of this sawfly caterpillar and I hope I never see one. Best of luck to you in saving your plants. They are a real treasure.

  4. I haven’t seen many Solomans Seal in Auckland area but when I visit Christchurch there is heaps – it must enjoy the cold winters. I don’t know whether the fly has turned up in NZ yet – but who knows – we have so many nasties from the rest of the world. The Bio Security have a hard job on their hands, especially when people try to bring unprocessed food and plants (WITH SOIL on them) in to our country. The very hot water solution sound feasible. Don’t grizzle about the loely hot summer – wasn’t last year a wet cold one? We are never happy! Except we have been having lots of clear blue days interspersed with rain!Gd luck!

  5. Can I add another ‘yuck’?! I’m starting to think there’s a sawfly for everything and I hate the way they come in hordes…. never just a single worm. Good for you for getting after them and good riddance!

  6. Right. Those are some disgusting critters, alright. The organic approach can be frustrating, as you sometimes just have to accept pretty serious damage to your plants and wait for the predators to achieve proper balance. Of course if the pest has no predators, then you can only get rid of the plant. Still, it is a good goal to avoid insecticides.

  7. Don’t send them over here! On the other hand, a little zip through the blender, a little garlic, lemon and salt — perhaps a nutritious, protein-based spread, and tasty, too?

  8. Oh what a shame Helen. If my memory is correct you are partial to the autumn colour of the foliage so you will miss out on that this year 😦 Away from home at the moment so can’t check on the health of my Solomon’ Seal plants. I had gooseberry sawflies decimate the foliage of one of my gooseberry bushes last month. I imagine that they must be relatives – not welcome creatures! I would not blame yourself as such creatures can do much damage in a very short amount of time.

  9. Most of my plants have suffered the same fate as yours, I think the only remedy is to cut them down, I put the caterpillars on the bird table, but the birds don’t even seem too keen!! The will be fine for next year.

  10. Mine appeared virtually overnight, Helen, in droves like yours, but hadn’t done quite so much damage as on your stripped leaves. I have tried feeding the gooseberry sawfly to the chickens before now but they don’t seem bothered, and I cut off the infested leaves of the polygonatum and put them in our green bin. I must look out for the scars you mentioned – but there far worse critters around and I do admire their voracity!

  11. Ewww, those look bad. Yucky in fact. Almost as bad as spiky plants! Wait . . . maybe worse.

  12. I sympathize, Helen. I’ve been picking them off (& photographing them too!) at the Priory. In the past I’ve just left the larvae; the plants still flower the following year but I’m hoping that removing them will allow the clump I have to increase in size. Interested to see whether removing them will have any effect on numbers next year. Dave


  14. I’ve obtained some of my Dad’s Solomon seal, and it lasted about 2 days before the sawfly struck, i’m going to pull it out and grow something less vulnerable in its place.

  15. I have the caterpillars on my Solomon’s seal every year – but they only damage the plants well after flowering. The plants come up every year as good as new…so I tolerate the sawfly. In fact, I find them interesting! I certainly wpouldn’t advocate the use of pesticides. Farmers use far too much of them out in the countryside, to the detriment of wildlife, so gardens, at least, should be poison-free zones.

  16. Oh dear just been in the garden and seen these disgusting creatures on my solomons, didn’t know what they where . I do now and have dealt with them accordingly.

  17. We have been getting Solomon’s seal lava for about three years now. It’s surprising how quickly they can sign of them last week and yesterday I removed over 170 of them! I will be back out again today to remove the rest . I also originally put them on the bird table but none of the birds were interested, so they are now put in a bag and put in the bin,Last year they attacked our silver birch, and made a fascinating orderly pattern by arranging themselves in a symmetrical line around each leaf, a bit like synchronised swimmers! Freaky!

    • The sawfly on the silver birch would be a completely different species – probably he birch sawfly. I wish people would be more tolerant of insects feeding on their plants in the garden – its all part of the natural world. Have a wildlife garden, I say and stop fighting nature.

  18. I love Solomon’s Seal. I live in Winnipeg, Canada — which gets as low as -45 in winter (so, yes, the plants can tolerate the cold!) — and not only is this plant good for this zone 3, but it is great in shady areas, and my back yard is very shady. I have not seen this sawfly here… but I have another problem with my Solomon’s Seal and have not found out anything to help me deal with it. My plants were looking nice and glossy green, and then fairly quickly, the leaves started withering and turning yellow and even a dried out brown. We’ve had a ton of rain this year, so it is not for lack of moisture. And in my neighbourhood, I have seen lots of lovely looking Solomon’s Seal without the problems I have. Any idea what would be causing the leaves to turn yellow and brown and wither… and what the solution might be?

  19. Sometimes life is too short. Our Solomon Seal came out last winter so no sawfly this year and there are plenty of replacement options.

    • I have a Solomon’s seal plant which is annually eaten by Solomon’s Seal Sawfly. As the damage is only apparent after flowering and the plant comes up as new each year, I don’t worry about it. Well, I do have a wildlife-friendly garden and insects, which are my main interest, are a fascinating part of it.

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