Friday 19 January 2018

Box blight & other fungal diseases

By Andrew Collyer - Practical Gardening

Andrew Collyer.
Andrew Collyer.
My beloved box hedges.
My beloved box hedges.

Keep a listen out for blight warnings

Euryops pectinatus

I clipped my box hedges this week and was delighted to see them looking in such good health.

Well reasonably so, as for the last three years I have been waging war on the dreaded box blight fungus.

Fungal diseases seem to be becoming more and more prevalent and virulent in recent years which probably has a lot to do with the mild dampness we seem to experience nearly all year round.Dutch elm disease was a warning decades ago. A common misconception is that the elm trees were killed by beetles but they just act as transport for the fungal infection. Ash trees are now facing a similar fate albeit infected by air borne spores and machanical contact.

To stop the spread of the fungus both trees block their infected water and nutrient carrying vessels that are harbouring the fugus. In doing so, and unwittingly, the trees cut off their life supply and die. The injection into the tree of a fungicide is the only cure and is just not feasible on a national scale. That said in Brighton England the council took it upon itself to treat its many elm street trees and it is now one of the last places in Britain and Ireland to see mature elms.

Escallonia, a common garden plant, has also fallen foul of a modern day fungal infection. During the summer months it seem relatively heathly but come winter this evergreen defoliates leaving a very sorry looking scrawny plant. There is nothing available to the gardener currently to treat this disease and while unlike Dutch elm and ash die back it doesn't appear to kill escallonia as it is only a leaf infection. But it leaves a pretty undesirable for a large portion of the year.

Getting back to my beloved box hedge I read frequently a few years ago that once infected the best thing was to dig up and destroy your box. Now it appears that the gardener is being encouraged to fight back and not succumb or at least not easily to the fungal invasion.

Since I first saw signs of infection a few years ago I struck up and stuck to a regime of feeding, spraying and cleanliness that seems to be at least controling the infection. From the very earliest spring, early March I apply via spraying a product called 'Top Buxus'. It foliar feeds and without chemicals, it uses copper, wards off box blight.

Or so it claims but I was using this solely when I first saw signs of infection so I also use a fungicide recommended by the RHS called Tebuconazole in the form of Bayers Fungus Fighter or an alternative is Fungus Clear Ultra which contains Triticonazole. This early preventative spraying is highly advisable as post infection is much harder to treat. I also apply a topdressing of fertiliser at this time of blood ,fish and bone. I then cut my hedge twice a year once at end of May to start of June depending on the spring and then again in September.

All formal hedges really are better cut twice a year this way, it keeps them thicker and helps to stop baring at the bases. I lay down sheets to catch as much clippings as possible, as box has small leaves cleaning up off grass or gravel is not very easy, this way there are less potentially infected or spore habouring leaves left laying around. I then repeat my spraying process of the box hedge with Top Buxus and Fungus fighter and I also spray with Fungus Fighter the soil around the base of the hedge where leaves and any spores might still be lurking.

Early July I go through the process again, sometimes I give an additional Fungus Fighter spray if the weather is humid or excessively wet in between times. Then in September ,when I clip the hedge again, I repeat what I did after the first cutting in May/June. With the way the weather systems are these days September can be better weather wise than July so I feel the hedge has plenty of time to harden off before the real cold temperature come along.

Wexford People

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