Daphne Ledward - Compost, Viburnum

DAPHNE'S COLUMN


COMPOST INJURY, COMPOST QUALITY, VIBURNUM Gardening, June 17 Last week I was potting up some zinnias, and as I put my hand in the bag of peat-reduced, multi-purpose compost, I felt a sharp pain in a finger, which I discovered was pouring blood. An investigation revealed a piece of toughened glass, about a centimetre in diameter with one very sharp corner. And yes, I was wearing gloves. The demand for using materials other than peat for potting composts is not new. First it was coir (coconut fibre), which was heralded as the salvation of the peat bogs. The first coir composts were difficult media, as they dried out easily and needed a great deal more fertiliser that the peat-based ones of the time. Then they got a bad press on hygiene grounds and the environmental cost of importation, and most gardeners tended to fight shy of them. Now recycled plant material has largely taken over as the replacement for peat, but there is still a long way to go to achieve the same results. Because of its origins, the composition and quality can vary greatly, even in different batches from the same manufacturer. Last autumn I tried an offer from a discount supermarket; this was unusable as it had set like concrete in the bag. Not wishing to waste it entirely, I tipped it onto my vegetable patch and can still see the lumps now. This year I decided to play safe and go for one of the well-known brands. Most of the bags contained a certain amount of definitely non-compostable material, such as pieces of plastic, string, paper and small bits of metal, which I would have preferred not to have seen, but didn’t worry about. It was only when I had the encounter with the glass that I thought a word with the manufacturer wouldn’t come amiss. I was reassured by an ‘assistant horticultural adviser’ that there had been problems with the supplier, and the factory had now installed its own screening machine. I was thanked profusely for notifying them of ‘my problem’ (theirs, surely?) and ‘rewarded’ with a £15 voucher to buy some more. Maybe I will, maybe not. If I do, I’ll keep a sharp lookout (sharp –get it?) for undesirable items. But it begs the question – if these are the foreign bodies in peat substitutes that we can see, what might they contain that we can’t? And until I can be sure that peat replacements are as hygienic and safe as good old peat, I will be reluctant to use them on a regular basis. And the finger? I’m a tough old bird and it’s healed almost without trace. Lucky, or what? Question Why has my guelder rose (Viburnum opulus) died? (pic to follow when it stops raining!) I don’t think it has. Your shrub has had a bad infestation of the larvae of the viburnum beetle. This skeletonises the leaves which then shrivel up. Generally, viburnums will produce a new crop of leaves that will be unaffected, but I find if the bush is badly affected, it is best to prune it back to a height of 60-120cm (depending on age and size) and it will send out new shoots from low down. At the first signs of damage next year, spray with a caterpillar killer.