Winter approaches and
our gardens need careful thought at this time, if we are to
avoid creating too much disturbance to over-wintering
wildlife. Many of the beneficial creatures that we encourage
to gardens and allotments through the spring and summer must
find shelter until the warmer weather returns. Hedgehogs
build leafy winter hibernation nests, butterfly larvae pupate
or adults find cool dark places to sit out the frosty weather
and ladybirds search for shelter from the cold in cracks in
bark, in log piles, deep in tufted grassy vegetation, hollow
flower stems or in
the foliage of conifers. Some creatures go about their
business as usual, particularly the smaller mammals such as
mice and shrews: our native wildlife has a variety of
strategies for surviving the winter.
All this means that
winter gardening is full of hazards – tidying shrubs may
expose hibernating insects or reduce roosting places for small
birds, and cleaning up borders removes valuable dead
vegetation where many insects, especially ladybirds and
lacewings, find shelter. There is one garden habitat that may
well be in need of work at this time though – the wildlife
pond is at its least active now and a little work at this time
can ensure that it is in tip top condition come next spring.
Autumn seems to be
arriving later and later, so your first task is to deal with
excess leaves that may still be falling. A few dead tree or
shrub leaves finding their way into your pond is no great
problem as long as it is not completely iced over for any
length of time throughout the winter. Leaves break down and
create a substrate at the bottom of the pond that many small
animals use for finding food, shelter and for breeding. Frogs
too sometimes spend the winter deep in the squidgy mud in the
depths of a pond so at least some of this substrate is vital
to your pond wildlife. Large quantities of leaves however,
especially species such as beech that are particularly tough,
contain tannins,
and break down slowly, can cause a build up of potentially
toxic gasses. So a little time spent removing excess leaves
is time well spent.
Although a good
covering of plants is essential for wildlife, it is important
to start the spring with a fair proportion of open water.
Wildlife experts recommend that a minimum of one third of a
pond surface should be open and accessible to flying insects
such as dragonflies and water beetles. These animals search
for new habitats from an aerial perspective – the glint of
open water can be spotted by a dragonfly from some height.
This means that your pond stands a better chance of attracting
new species of insect if the water is visible from above.
Frogs and toads tend to need space for mating and egg laying,
and will often choose open water for these activities rather
than densely covered water. This means that at least some
vegetation can be carefully removed at this time of year,
especially any species that proliferate rapidly. Water
soldier, if it likes your pond, can produce its vegetative
offspring, initially attached to the parent plant, at an
alarming rate. However these plants are easily removed as
they are free floating and not firmly anchored to soil in the
bottom of the pond. A rake handled with care and avoiding the
pond liner, can be used to gently trap these spiky floating
plants and manoeuvre them to within easy reach. Bogbean too
can become a problem, albeit an attractive one. Its spreading
stems will rapidly move across the surface of the pond,
obscuring the open water. The best implement for this plant
is a long handled pruner. A quick snip of the stem near the
water’s edge will deal with it, and it can then be caught with
a rake and brought ashore. A pruner that also holds onto the
cutting is especially useful here.
Other more difficult
to control plants should be thinned out now but this may be
easier said than done. Rapidly growing marginals such as burr
reed, sweet galingale and some sedges and irises can be
difficult to control and are best left out of a new small
pond. If you already have them you have no alternative but to
move in with a heavy handed approach and do your best to
uproot those that are surplus to requirements. Again, take as
much care as you can to avoid tearing the liner – these can be
repaired but it is best to leave any plant that you suspect
may have rooted through. Oxygenators can also be thinned out
this month, but bear in mind that they are the life blood of a
wildlife pond and some pond experts would say that you can’t
have too many! All plants removed from a wildlife pond should
be left on the pond side for a few days to allow creatures to
find their own way back to the safety of the water.
Alien invaders can
also be dealt with at his time. New Zealand pygmyweed,
otherwise known as New Zealand stonecrop (Crassula helmsii) is
a serious problem in our native waterways. Sadly lots of garden
ponds seem to have this invasive plant now and it must be
dealt with whenever possible to prevent it taking over
completely and shading the water to the extent that wildlife
no longer thrives. The best that we can do at present is
remove it by hand as thoroughly as possible, taking into
account that it will be an ongoing problem. Research
continues into the treatment of this persistent thug, but as
yet there is no solution to the problem. Parrots feather (Myriophyllum)
is another invasive plant though less problematic than
Crassula and easier to remove. Both of these species should
be allowed to dry out thoroughly before composting, and never
disposed of in green waste bags, left in the countryside, or
given to friends.
Once these tidying
tasks have been completed one more creative job can be
undertaken. If you have small plants or plugs of suitable
wetland plants available, these can still be added to spaces
in marshy pond borders or planted on pond ledges – a good
opportunity to add new species to a wildlife pond. Native
wildflowers will be relatively dormant now and will come to no
harm through the winter months. Planting now will give them
an opportunity to settle and get ahead in the spring.
As the winter
progresses we have no knowledge of what the months ahead will
bring. Prolonged periods of frost, snow and ice seem to be
things of the past for many of us, but keeping our ponds free
of surface ice is still an important task. Make sure that you
check your pond on a regular basis on colder days. If
continuous ice is still present after midday, a ‘breathing’
hole should be made in order to prevent the build up of any
gases beneath the ice surface. This is most effectively done
with the base of a metal saucepan, full of very hot water.
Simply rest the saucepan on the frozen surface until a hole is
gently melted through. In very icy conditions your pond may
not provide easily accessible drinking water for local birds
so try to ensure that water is available to them in an
additional container of some sort.
The next couple of months
can be frustrating if you are a restless gardener but keeping
an eye on your garden wildlife residents and visitors and
ensuring they have what they need may well satisfy that
gardening urge until the weather warms again. |
