ISSUE 2157 Saturday 21 April 2001
Thorny problems
Gardener and lecturer Helen Yemm answers your questions
Blast off
Many of the buds on my large rhododendron look as though they are covered in soot. They are also slightly bristly. Is this rhododendron bud blast? What should I do about it? J. Fellowes (via email)
Bug attacks: rhododendrons can suffer from bud blast caused
by the leaf hopper spreading fungal spores
YES it is. Although bud blast is a fungal disease, it is generally accepted that spraying with a fungicide is ineffective.
The spores are spread by a large and rather handsome leaf hopper that is most active on sunny days from about June to August. In my garden the problem seems to be far worse in a spring following a hot summer.
Your attack on bud blast should be two pronged. First, remove all the buds that you can reach as soon as you can - they will not flower and will merely harbour the disease. Secondly, keep an eye open for the pale green leaf hoppers when the weather warms up.
They are easy to spot, flying off erratically as you approach, showing an exotic flash of red on the undersides of their wings.
On the first sighting, spray the entire bush - and any neighbouring shrubs, since the little beasts will just migrate until the coast is clear - with Doff Systemic Insecticide.
If you use a non-systemic insecticide such as BugClear, you will have to spray more often.
Fluffy nuisances
Philip Cole, London; Christopher Greene, Wrexham; G. Williams, Penmaenmawr and many, many more . . . have a problem with marauding squirrels ("fluffy-tailed rats" was how one of you described them). They dig up bulbs, pinch camellia and lilac buds and so on. You want to know if there is any way they can be stopped.
As far as bulbs are concerned, a barrier of chicken wire below the surface of the soil does put them off a little - nylon net won't do, they just chew through it - but the sad fact is that there is absolutely nothing you can do to persuade squirrels to leave your garden alone.
Taking flight
Have you any suggestions as to how I can stop herons from taking fish from my garden pond? Edward Sant, Camberley, Surrey
According to the people in the know at my
local fish farm in Hawkhurst, the best way to
stop herons stripping your pond is to put a
barrier of fishing line 18in (45cm) above the
ground/water surface all around the edge of
it.
It is almost invisible to humans, and if herons
try to step over something this high, they trip
up. This I should love to see.
As you have no doubt discovered, plastic
decoys only work up to a point, while
submerged netting is not advisable because
fish can get stuck in it.
A friend of mine with a smart formal
rectangular pond unwittingly found a neat solution to her heron problem. She
had a child-proof iron grid made up by her local blacksmith. The grid is on legs
and stands submerged a few centimetres under the pond's surface. Fish can
swim through and over it and dart away under it, while herons stay well away.
Compost scents
How do I make decent compost like my mother-in-law's fragrant, crumbly
stuff? Mine takes for ever to rot, smells and is always rather slimy and
clod-like. What am I doing wrong? Dain Keating (via email)
This is such a common problem, and the one that, sadly, puts far too many
people off the whole composting business.
It sounds as though your compost is too wet - possibly there is an imbalance of
ingredients, and too much kitchen waste is going into your bin.
You should aim at a roughly 50/50 dry/wet balance, particularly in winter. You
could add some straw or more crumpled up paper (at last a good use for all
that junk mail) to help lighten it up, and make sure your slatted bin has a cover
on it.
There is a lot to learn about composting, and it helps to understand the process
a little better. Did you know, for example, that there are two different ways to
rot stuff down, one based on the fast build-up of heat and the other on the
slower action of worms, woodlice and micro-organisms and so on? Also that
autumn leaves, which contain no chlorophyll, should be rotted down entirely on
their own and take much, much longer?
The HDRA garden at Ryton, near Coventry is having a demonstration day on
Bank Holiday Monday, May 7, to coincide with Composting Awareness
Week. In any event, a visit to the HDRA gardens at Ryton or Yalding in Kent,
where the composting demonstration areas are helpful, may well change your
gardening life forever, as it did mine.
Plant hunting
To all those who are emailing and writing to me asking where they can get
hold of this or that plant, I cannot recommend too highly the RHS Plant Finder
(the 2001 edition will be available in late May, price £12.99, also available on
CD ROM). This invaluable reference book, with its unique, and initially quite
mystifying, coding system soon becomes indispensable to plant lovers.
As well as being able to source plants all over the country, you too will soon be
discussing the merits of nurseries such as SPer and MAsh and CHad along
with the best of them.
Write to Thorny Problems, Helenyemm1@aol.com or The Daily Telegraph
Gardening, 1 Canada Square, London E14 5DT. Helen Yemm regrets that she
can answer letters only through this column.
-- Anonymous, April 26, 2001