The season for this dreaded pest has started again and box hedges and trees in my area - south west of London - are suffering or being completely destroyed in a very short time frame. I appreciate many of you probably have pesticide spraying licences, but I do not (far too costly I'm afraid). I am willing to recommend sprays that I have read about that can be used by anyone such as xentari from the Netherlands. In fact I have ordered some as I have one lone box bush which did get attacked a bit last year. I have had several clients lose large areas of box to caterpillar destruction, and I see it in gardens wherever I go in this area. If it hasn't reached your area yet, it probably will and the destruction is fast and devastating. Whilst plants can recover, they won't if repeatedly attacked and the moths reproduce between April and October. That's a long window of regularly spraying to keep the caterpillars at bay. A friend recently grubbed out a hedge that had been there over 40 years, as the RHS and two garden centres had all given her a message of either little hope, or a life of constantly spraying to kill the caterpillars. I find that slightly irresponsible on first hearing, but in reality have found my attitude has become similar, as if I as a gardener don't go and spray every two weeks, the caterpillars will probably destroy the hedge sooner or later.
Another client of mine also has a more than 40 year old hedge, two circles of it, one inside the other, overall about 19 metres in length, half a metre high and a bit less in width. I picked off over 100 mostly very fat caterpillars off it in one more badly affected area of less than a metre as I had no other means of helping on the day and she hadn't noticed it beforehand. Has anyone had success with a spraying regime, was it with xentari and how much commitment are we talking about to keep them at bay?
On Twitter I found a post from last year which talked about wasps either eating the caterpillars or perhaps parasitizing them? I'm not sure what's going on there, and I'm not sure the guy who posted it completely understood what was going on as he'd been called in to spray the hedge, he wasn't an insect expert. Has anyone else had experience of wasps effectively getting rid of the caterpillars, and is there a way to encourage wasps (I saw a bee or hoverfly on the hedge I refer to above - was it doing a similar thing?). I want to give my clients a message of hope, I want to feel hope myself. I commented on it to my local garden centre, who still sell loads of box, including one huge umbrella shape plant that must have cost at least £500, But despite virtually every plant in our area being attacked, I don't know if they warn people that this could well happen.
Any thoughts, successes, failures or opinions on whether this battle is worth fighting, and perhaps any ideas for good alternative plants that you've planted instead (apart from privet) would be greatly appreciated.
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Thankfully not seen any evidence up the hill here in High Wycombe. I'm hoping the Chilterns winters are too cold for the eggs to survive.
My only suggestion would be to feed feed feed. Maybe something like seaweed to get your plants as strong and healthy as possible to help them recover.
Oh, and lonicera is a good alternative to box.
xentari is ususally the easiest solution to suggest as domestic clients can purchase adn spray it themselves. Where a client has a lot of box hedging and topiary, I've suggested pheremone traps as well.
there is a parastic wasp which was being trialled in France (I think) Admit I havent looked up results for that yet I know it does the usual of laying its eggs into the box larvae so the larvae then provide food for the emerging wasp. Many clients find that idea too gross when I've suggested for other pests...
feeding - need to boost the immune system of the box plants so a phosphorous based fertiliser rather than nitrogen initially.
As for alternative plants - depends on what the box was being used for, ie hedge or specimen topiary; and whether the site is sunny, shady,
wet, dry; and whether the client wants 'instant garden' type replacement; is it a period style garden with other period plants, etc
I've used: -
rosemary
santolina
sarcococca
teuchrium
yew
and some more 'random ' ones
hope that's helpful!
As per other thread -- really usefull to keep an eye on this main website for tracking outbreaks :
Well over 75 outbreaks recorded in last 4 weeks : https://www.ebts.org/bmctracker/
The heatwave last year seemed to allow the moths to have 3 whole life cycles and fly a long way from the south east and london. Heres in Glocs we had many first ever recorded outbreaks from August of last year. So regardless is you think your area is presently free -- it wont be for long and if the map shows an outbreak near you -- it would be best to prepare if you look after lots of Box
The general advice from the Boxwood society is here : https://www.ebts.org/wp-content/uploads/2018/04/2018-Box-Moth-Flyer...
Im sure Progreen or others can advise but if you have a suspected outbreak you probably need to get a spray guy in and apply DECIS or similar which appears to be quite effective. This is then followed up by a regular bacterial spray like Xentari or Dipel -- not sure if Dipel requires a spray cert - but appears to be very similar to Xentari. The use of Moth traps is important to catch the males before the they breed.
IMO no garden designer should plant box anymore without total transparency regarding its life expectancy and the large financial / toxic upkeep. Plenty of designers out here continuing to mass plant box and do not tell the customer of its issues -- all they have done is put small print in the bottom of a contract to cover themselves.
Plus one for teucrium
RHS nemetode study in Feb this year : https://www.ebts.org/2019/02/rhs-testing-of-nematodes-for-basf/
Results were only 49% effective compared to almost 100% effectiveness of Dipel/ Xentari where product came into contact with the caterpilalers.
I found this RHS comment very conflicting as usual when it comes to spraying issues :
QUOTE : Note: neither Dipel or XenTari are currently registered for domestic use in the UK.
Thats typically odd as TopBuxus that makes Xentari advertise and seel it direct to the domestic market !!
Personally I'd get rid of them Angela. If the moth dont get them the blight probably will sooner or later.
I also like the idea of Teuchrium, LJN yearly subscription validated again:-), also Choysia works well in some situations like massiefs.Im trying Ruscus asculatus' John redmond' at the moment for low hedges. It's difficult to source at a good seize cheaply, and I am not sure how it will respond to tight pruning in the future,if at all. but it's tough as long as it doesnt sit in wet ground. Excellent in shade. Red berries in winter too which could be a real crowd pleaser..
teucrium lucidrys is an excellent very tough plant and very suitable to low hedging -- unfortunately its doesnt seem to grow well over 45 -50 cm so for lower hedges perfect -- im yet to grow 'fruticans' or 'chamaedrys' but will this year -- trouble is nothing gives the same effect as box - there are new box varieties coming to market which are supposed to have resistance to various things - but we will have to wait and see -- agree Paul -- its a worthless fight once you have multiple attacks - as seen throigh most of mainland Europe -- the upkeep is too expensive and too toxic and doesnt work long term
Hi Dan ,
I will also get busy with Teucrium as 40-50cm would be ideal for some replacement work I need to do. There was alot of talk here a while back about a buxus disease resistant variety. Belgians love buxus so It will be interesting to see what happens. For the moment it has come to the end unfortunately. Superb plant when grown well..
In Europe these guys are supposed to be releasing 4 new buxus hybrids with some blight resistance this year : https://www.herplant.be/en not much info on theior website about it -- but might be worth a mail.
In the USA -- these guys will also be releasing supposed resistant types : https://www.newgenboxwood.com/
Think we wil have to wait and see for results on these.