Talkback: The trouble with berberis - Page 2 - Talkback

25/05/2009 at 10:03

Last year my enormous berberis hedge was eaten. We had no idea what was wrong until we saw tiny caterpillers climbing the house wall! The leaves have all returned this year and my hedge is looking beautiful, but I have noticed a multitude of flies around the base of it, I just know it is going to happen again! I dont want to spray, I have plenty of birds in the garden but they dont seem interested in delving into my thorny hedge. What can I do?

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26/05/2009 at 14:43

Reply to Margaret If the sawflies are about, then it will not be long before your bush is being shredded again. I recommend the upturned umbrella technique. Put it under the branches, give them a bash and deal with the fallen caterpillars in whatever way you see fit.

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31/05/2009 at 21:38

I think we have the same thing. Two berberis, young plants in a tub. Small up to 1cm larvae, as far as I can see a uniform dark grey, lots of frass, of course lots of leaf loss. Interestingly, and not so far mentioned in this blog, a fine network of what appear to be very untidy spider web like filaments all over the plant. Anyone else seen these?? Maybe this isn't the dreaded sawfly?? Finally a similar but much less serious outbreak is affecting three small Escalonias, also in pots in an oak barrel.

Gardeners' World Web User

09/06/2009 at 13:43

Up to now there are no signs of leaf loss on my berberis. It was trimmed on 6th June and seems okay so far. I'm not yet convinced that we've escaped the attentions of the dreaded sawfly, but immediately after trimming there were half a dozen starlings feasting on something in the hedge!

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18/06/2009 at 21:17

It's happening, my hedge is being shredded. It's uncanny, there's no sighting of caterpillers but the hedge is being eaten, fast. I realise that this is going to continue ever year. I might go with phil f s' idea and grow a climber through the hedge, any suggestions as to what species? I live in Northamptonshire by the way.

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22/06/2009 at 12:25

Reply to everyone. Take some heart from the fact that the hedge which started off this blog and comment trail is apparently untouched this year. There is no sign of adults or larvae. ....it's a mystery.

Gardeners' World Web User

22/06/2009 at 15:22

Ihave recently had a whole hedge row of Berberrsis stripped of all leaves. I had no idea until I did some research on the internet and came across a creter called 'Sawfly'. Having trimed the hedge, I found millions of Caterpilla at the base of my compost bin, small grey and very active. No other plants in the garden had been affected. Gathered a bucket full of these together and burnt, small numbers still on the hedge have been spayed with an insecticide. Having the hedge for more than 10 years, this is the first time that this has happened, I am now told that these bury themselves in the ground and pupate. This is devastating, will the hedge survive? will I now have the same problem every year?

Gardeners' World Web User

24/06/2009 at 11:38

This morning I have found the complete defoliation of my berberis here in Somerset. Being near the front door it was in all it's glory on Saturday, this is indeed a rapid devestation. I collected some larvae and one adult for identifcation plus photos which has led me here to this site. I too, am going to spray with insecticide.

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26/06/2009 at 19:40

These unwelcome sawfly caterpillers appeared on several berberis thunbergii plants in my garden last year and seem to be just as active this year. Disliking insecticides, I have resorted to shaking the plant with a sheet underneath (they drop off easily) and then destroying.

Gardeners' World Web User

29/06/2009 at 20:32

Two pairs of chaffinches are devouring the caterpillers as fast as they can. It is too late for my hedge this year but maybe the chaffinch is the natural predator I've been hoping for.

Gardeners' World Web User

01/07/2009 at 19:32

We have found our berberis almost completely stripped within 2 weeks with all of the tell-tale signs mentioned above. Sure enough it is the dreaded sawfly. First year that it has happened for us. We are going to nuke them!

Gardeners' World Web User

05/07/2009 at 18:24

I had advice from no less than RHS head entomologist last year after my berberis was left a netcurtain thanks to the sawfly. He said treat with pyrethrin based insecticide but not during flowering - and do it regularly. He also mentioned that at the end of the season the pupae do overwinter in the soil. Therefore it might be a good idea to get on top of the population before autumn. I was hoping last winter may have doofered the sawfly, and was optimistic come 2 weeks ago when there was no signs of munching. However, a weekend away and now half the bush is destroyed. I have sprayed twice this week with soapy water. I have just been out for a foray and collected at least 30 in soapy water in a cup. I'm hoping if I keep this up for a few weeks I may get on top of the population. If its the same next year I think I will have to resort to replacement - my garden is to small to have a non-performer.

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14/07/2009 at 12:06

The leaves are returning to my devastated hedge! This didnt happen last year so I am thanking the chaffinches. I'm wondering if I treat the soil under the hedge I can deter the caterpillars that are pupating over winter from emerging as sawflies.

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25/07/2009 at 12:10

For the past two years our berberis has been ruined by the sawfly with every leaf eaten. This year we spotted them early after only a few leaves had been damaged. A thorough shake of the leaves casuses thenm to fall to the ground. The bush was then saryed very thoughly with soapy water and so far this year we have had no further trouble. We have plenty of birds in the garden but they really don't seem very interested in helping out.

Gardeners' World Web User

29/07/2009 at 08:03

Update Thanks for all the continued comments. The sawfly is obviously still expanding its range in this country, but at the same time once defoliated bushes are recovering and appear untouched. The sawfly is unlikely to have disappeared from these sites, more likely it has suffered bad weather or predators or parasites or diseases at some key point in its life cycle. It is this which will hopefully keep it in check now that it is thoroughly established here.

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13/08/2009 at 10:40

I have a 10 year old upright berberis in my garden and was astonished to see strange looking black flies buzzing around it. A few weeks ago I noticed the leaves being eaten by small greyish grubs, so dusted the plant with derris dust. The grubs are now gone and the berberis is starting to grow more leaves.

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19/08/2009 at 18:29

Oh we have a rather large gathering of these little sods, feasting quite greedily! They way they have ravaged my poor little berberis bushes I am sure they must be related to the locust!!!!

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24/08/2009 at 18:52

My 10 foot berberis has been eaten completely in the past 8 days :-( - pesky caterpillars!! they were small green ones, approx 1.5cm in length.I've had no option but to cut it down and dig it out - I really dont want the blighters back - now to look for a large plant to fill the gap

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29/08/2009 at 12:16

The large berberis in my garden in Wiltshire has been attacked 3 years running by these caterpillars. This year they came early in the summer. The leaves grew back, but a few days ago I was devasted to see that it had been stripped again! If they've gone back in the earth, what form do they take at that stage in their lifecycle? I'm prepared to try digging them out to get my revenge.

Gardeners' World Web User

31/08/2009 at 10:29

This might be of some use Pat Sawfly Sawflies are the smash and grabbers of the insect world. Few pests make such an impact, so rapidly, on your plants. Go away for a weekend and you may return to find your berberis, gooseberry bush or your aquilegias stripped of all their leaves. Each species of sawfly affects a specific plant, so there is no danger of sawflies from your gooseberry eating your Solomon’s seal (polygonatum). There may be just one or several generations each year and the adult flies hatch, mate and lay eggs on the host plants. They rapidly devour the foliage until large enough to crawl into the soil, pupate and emerge as adults.