Case study: Box Tree Caterpillar infestation, Parliament Square, Westminster.

BoxMothSOS successfully dealt with a box tree moth caterpillar outbreak at the landmark location which threatened to cause thousands of pounds worth of damage to historic hedging.

ON arrival at the famous square it was immediately evident that the formal box hedging on the northern border had a severe infestation of box moth caterpillar and that the ornamental Buxus was at risk of complete destruction. The hedge was partially defoliated and the distinctive green and black caterpillars were soon discovered.

The voracious caterpillars had begun defoliating the box hedging at a tree-shaded corner of the border and munched their way through metres of priceless plants. If left to continue their rampage, the cost of replacing the historic hedge would have run into thousands of pounds.

As with all box tree moth caterpillar infestations, time was of the essence in tackling the outbreak and preventing further damage. Our experts actioned a tried-and-tested drill to save the hedge and prevent the landmark location from becoming an eyesore.

Caterpillars were meticulously removed by hand and the hedge was then thoroughly sprayed with a special biological insecticide. This water-dispersed solution is harmless to other insects including bees and butterflies but will kill caterpillars ingesting the treated foliage in 24 to 72 hours. The hedging at the Square was treated in around four hours.

Our RHS-qualified expert returned to the location 48 hours later to inspect the box hedging and check the treatment had been effective. It was evident the biological insecticide had curtailed the caterpillar infestation. 

We recommended further preventative treatments to deter re-infestation during the summer months together with an irrigation and nutrient care package to help the damaged box hedging recover faster. Our proven service is available to both commercial and residential customers between March and October when the caterpillars are active.

Prevention is better than cure...

We recommend owners of Buxus hedging in known box tree moth hotspots opt for preventative treatment in the Spring to deter infestations. Check box hedging regularly for evidence of caterpillar activity including defoliation, webbing and frass. Be thorough and look in shaded corners where the caterpillars prefer to be out of direct sunlight. Contact us as soon as possible should you require our services. The faster an infestation is identified - the faster we can treat it. Our treatment prices are fair and competitive and based on the volume of box hedging to be treated, the time it will take to treat it and the amount of biological insecticide required. In all cases the cost of treatment will be significantly less than the cost of replacing defoliated plants. We have successfully treated severe defoliations and nursed leafless, damaged hedging back to health.  Buxus has an incredible ability to recover provided it is protected from further infestation. However, every case is unique and the success of recovery will depend on multiple factors from the severity of damage to the quality of after care.  In the event that plants are too damaged to be saved, we can provide and plant replacements or recommend alternatives to Buxus such as Ilex crenata. 


BoxMothSOS is part of Metroscapes - a professional and reliable provider of horticultural services. Our small and dedicated team maintain some of the capital's most familiar green spaces. Our gardeners are RHS-qualified and work to high standards and sound horticultural principles to deliver bespoke grounds and garden care to our valued commercial and domestic customers. Our services include lawn care, hedge clipping and cutting, planting and weed control. Metroscapes operates in London, Surrey and Berkshire.

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