Tuesday, 12 August 2014

Water problems and sexton beetles

Common sense and undertakers
      A lot of gardening problems can be solved using common sense. A bit of careful thought is often more rewarding than waiting for the Gardener's Question Time team coming up with the answers: I've got this ornamental grass Hakonechloa macra 'Aureola', growing in an urn at the end of the garden. During the recent hot spell I noticed that there was something different about it and a closer examination showed that the leaves had shrivelled, leaving almost a skeleton. Seasoned gardeners will immediately recognise the signs of water deprivation but newcomers may be tempted to think that some dread disease has taken hold and dispatch it to the compost heap.
Hakonechloa before watering
A few hours after watering
      When many plants are stressed due to water shortage, the initial reaction is to decrease the size of the leaf pores by shrivelling, lessening the transpiration of water into the atmosphere. This is done in the hope that it will either rain soon or the guy in the silly hat will come along with a watering can. In this case the latter occurred and you can see the result in the pictures.

      Although the Hakenochloa can grow in some pretty dry areas of woodland and mountain in Japan, it has the potential for its roots to explore for water over a much larger area and depth than a pot allows it. This is a limit many plants suffer in the artificial environment of a container and knowing it can be the difference between good and bad results: for example, growing Hydrangeas in pots can be rewarding but success is dependent on recognising that they are water junkies and need daily replenishment. A compost rich in organic material helps, acting as a sponge to retain water, but the fact that leaves and flowers form an almost impenetrable barrier to rain getting through means that they need as much help from you as possible. And don't forget plant nutrients, these are soon exhausted by big roots in a small pot, so a bit of  fertilizer every now and then will be well received. One with high potash content, like tomato or rose food is best for encouraging more flowering.
Hydrangea macrophylla - a water junkie
      So, the difference between a good gardener and the one who freely professes to 'kill everything I plant', is often just a matter of how much thought is applied. Maybe we can't all become Titchmarshes but we can avoid a lot of death in the garden. And this brings me to another aspect of dying: the afterlife.

      I was walking with a mate near Malham, in Yorkshire, when I spotted a dead mouse on the path. This may not seem particularly exciting but there was something strange about it. When I bent to look closer, I could see that it was rather flattened and in the same category as Monty Python's parrot but then........"It moved", I bellowed, "the bloody thing moved".
Sexton beetles
      Sure enough, the body was making some sickening undulations as if trying to rise from the dead. I'm not frightened of mice, but deceased ones coming back for another go take a bit of getting used to. However I needn't have worried because the causes of the resurrection suddenly emerged from under the body - beetles, big orange and black ones. These were sexton beetles and they are attracted by the smell of corpses. It seems they sometimes work in a group, digging under the body until it sinks into the hole they have made. After exuding antibacterial and antifungal secretions over it to prevent the smell attracting rivals, they then cover it with soil and the females lay eggs either into the body flesh or just under it. The larvae which then emerge eat their way to adulthood, feasting on what their parents have left of the meat. 

      This is the perfect topic for an after-dinner speech if you want to find out what everyone's had.



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