BIOLOGICALLY SPEAKING
So if the surface of the pool needs to be
clean for some sort of aesthetic satisfaction, it is no less important from a
biological point of view. Traditionally we should be about to have the first
frosts of winter, at which point things begin to grind to a halt below the
surface. As the water temperature begins to drop to around 10°C the frenzy of
fish and beasties gobbling each other up begins to slow down. At 7°C fish should
not be feeding at all. At 5°C most biological activity has ceased, and from 4°C
and 0°C water does something no other substance does on earth, and that is that
instead of the more dense cold water sinking to the bottom of the pond, the
colder water becomes less dense and stays on top. Here it will freeze solid
below 0°C and the water underneath for a few more degrees has a protective
blanket. At least no more muck or detritus can drop in, but any that is already
in there is ready to start rotting as soon as temperatures begin to rise. The
microbes responsible for this process need oxygen and this demand will activate
a long time in advance of the higher plants that can oxygenate the water
effectively, start to do their job. This combined with the very slow but
measurable metabolism of the fish and other sleeping pond life, will put
tremendous pressure on a biological system of a dirty or small pond. So
when it is iced over, ensure there is a hole in the ice for a bit of ‘gaseous
exchange’.
 |
Melt the hole with hot water or a pool
heater. Breaking the ice stuns the fish |
.
CLEANINESS IS NEXT TO BEING A PRETTY MUCH GODLIKE FIGURE, WHICH BRINGS OTHER
RESPONSIBILITIES TOO.
Any leaves you can prevent from falling in delays the day
when you have to do that Almighty style Apocalyptic clean out; so net them off
as soon as they land. Dredge out with a net as many you can that sink.
Lilies: any diseased or mottled leaves of retiring lilies
should be given a gentle tug to part them from the parent tuber before they sink
to rot below.
Floating plants like Water Lettuce (Pistia stratiotes) and Water Hyacinth (Eichornia crassipes) must be taken indoors and kept in light frost-free shade. Water Hyacinth
can be potted up into a light, merely moist compost. Water Soldier (Stratiotes
aloides) will sink to the bottom before the first frosts
whereas Frogbit (Hydrocharis morsus-ranae ) and Water Chestnut (Trapa
natans) form nuts or buds that sink to the bottom to rise again the
following year to form plantlets. Unfortunately the Frogbit will fall prey to
predatory snails and the Water Chestnut is unlikely to form nuts in our climate,
so they need rescuing to a pan of muddy water in good time before the party is
over, so they can do their thing in the warm protective ambience of a greenhouse
or light shed.
Pioneering marginals like Bog Bean (Menyanthes
trifoliata), the Spearworts (Ranunculus flammula and
R. lingua’ Grandiflora) and Parrots Feather (Myriophyllum
aquaticum syn. proserpinacoides) that seem intent on
investigating the outer reaches of their universe should be cut back to home
base: show them what you’re made of. The same goes for those Hell’s Angels of
the pond margins, the Reed Maces ( Typha angustifolia and Typha
latifolia), and any of those suspect ‘Reedy’, ‘Rushy’ looking things that
don’t seem to do much, apart from grow. Feel around
the baskets to see which plants have linked up in a firm vegetative bond. A bit
of basket busting may be in order to sort them out. If the problem is not too
bad, you can leave that little nightmare until spring.
Tender marginals need to be removed wholesale. Canna lilies
can be potted up and plunged into a bed in cold frames, otherwise keep them cool
but frost free and dry along with all the other exotics you have been tempted
buy over the last few months. Once upon a time Arum lilies (Zantedeschia
aethiopica ‘Crowborough’ ) and Lobelia cardinalis /(TRANNIE
14)/ were treated with the same respect, but now our winters seem quite bearable
to them. The more exotic looking yellow and spotty leafed Zantedeschia
elliotiana , Z. pentlandii or the pink tinged Z. rehmannii
should have been dried out since mid-July. Store them under greenhouse
staging well above freezing. Bring them to life again in February.
APOCALYPSE NOW?
If ‘Apocalyptic clean out time’ does seem imminent and you
are reading this during that mild patch of autumn like we often have in October
in the UK, the time to do it is now. How will you know? If when you are dredging
for lost leaves the net comes up full of last year’s half rotted maulm and it
seems unfathomable, or if smelly bubbles break the water surface as you
investigate the depths with the net then the situation is serious.
If you decide it is necessary, one consolation is
that you will find the job more bearable now than you would in late April. The
water will be warmer and there will be less chance of upsetting the development
of tadpoles or herpetological nuptials. Leave the dredged gunk and detritus to
drain on the poolside to allow any early-to-bed fauna to make their way back in
for their winter snooze.
If you decide on the tactics of a jolly good dredging then
a partial water change of one third to a half is advisable to dilute the
disturbed toxins released from the pool sediment. This is a routine for serious
fish keepers at this time of year anyway. Let the fresh tap water fall into the
pool from a height and treat with pool conditioner to knock out the chlorine and
other vileness they put in tap water.
“TO NET OR NOT TO NET JOSEPHINE ?”
“Here lies the rub!” If we are to make our pool all pretty
and pristine for the winter months what aesthetics are there in a great plastic
net draped over it for the next four months? If the pool is bubbling with a
school of Koi carp, every bit, fin and gill worth their weight in platinum
whilst a flock of Herons circle overhead like African Desert Vultures, then the
obvious choice is to net. If there is a phalanx of willows precipitate to the
pool edge with a prevailing mistral that will force-feed their load of salicylic
acid ridden leaves into our precious pool – then again, net.
But some trees have small leaves that curl up and wiggle
through all but the most tightly woven mesh, like the Acer dissectum or
the Gleditsia, in which case netting can then seem a pretty
pointless exercise. Also if there is a persistent fall from variety of trees
from the Holme Oaks in midsummer, with Robinias doing an early drop right
through to the late Ash keys and tenacious young Beech, you could be netted for
most of the year.
If the pool is fairly self sufficient and well established
and there are not too many trees about ready to loosen their foliage fall in the
compass bearing of your pool, perhaps a compromise of netting from late October
to December is in order. This will mean cutting the pond edge plants back to
less than a third to allow the net to be pegged into place and leaving an escape
route or access point for animal traffic – for not only the residents of your
pool, but yours may be the only watering hole for all sorts of beasties for
miles around.
“NOT NETTED, NEDDY”
Of course your pool may be too big to net or it may be
equipped with all the refinements of sludge sucking filters and surface skimmers
providing the sort of sterile sanctuary that most swimming pools don’t even run
to, thus making leaf nets superfluous. For whatever reason not to net, you can
opt to take full advantage of the scene you have created or will create.
Clear the surface. Light to the water surface is desirable
in the winter months. You have probably already cut back the fleshy leafed early
risers like the Marsh Marigolds (Caltha palustris), Bog Arums (Calla
palustris) and the Water Forget-me-Not (Myosostis palustris), but
leave the long grassy foliage to waft around in the breeze adding life to a
seemingly lifeless scene. These reeds, rushes and grasses will double as cover
for animals coming and going from the pool.( In small water gardens though, it
may be necessary to remove the seed heads before they shed highly viable seed to
all four corners of the neighbourhood.) Come the emergence of new growth in
spring when the Marsh Marigolds burst into yellow flower in early April, you
will have hardly noticed the flower free interlude.
If the frosts are slow to arrive, the foliage factor
from some of the variegated water plants is a major bonus. The sword like leaves
of the Iris laevigata ‘Variegata’, the variegated scented rush Acorus
calamus ‘Variegatus’/ or the small tufty A. gramineus
‘Vareigatus’ are late to die down and are up early spring, brightening up
the most moribund boggy patch. The variegated Manna grass(Glyceria maxima ‘Variegata’) and the definitely evergreen and variegated Gardener’s garters (Phalaris
arundinacea var. picta) add a splash of colour all year, but being somewhat
rampant and difficult to contain, after the first year you don’t where they are
going to come up next.
THE EASE OF FORMALITY
Formal water gardens in winter, with strong ‘bones’ of hard landscaping, can
show how the water surface works in a visual combination with stone, brick or
grass surfaces, or as a reflective surface. Life and movement can be added with
fountains and rills. Without water moving upwards or outward then formal clipped
plants give height and balance and softness in a third dimension. Box, Myrtle,
Bay, Privet and Holly, (also Yew well away from the pool), are favoured for
topiary.
With the formal harmony reflected, or even just a small
part of it reflected in the water, it emphasises your awareness of the third
dimension. It is like the Moorish love of stargazing into a pool, it makes you
appreciate more the creation around you to see it as a reflection, because it
looks new and different.
This can happen in more informal gardens but you are more
dependent on large plants to help create the structure in your design. Trees
that colour up in the autumn can be grouped together to form a cathedral in a
kaleidoscope of colour, transfixing in a gently moving reflection.
TAKE A LEAF FROM THE JAPANESE
The Japanese build their gardens for all seasons. Part of
the purpose of a garden is to reflect the time of year in the scene laid out to
view. A view that seems static in itself, unchanging from year to year; but it
changes from season to season. In winter the harmony between the various basic
elements of stone, evergreen shrubs and trees and water is most obvious. The
balance is not formal but is derived from the almost inimitable feel that the
true master Japanese garden designer has for these elements and the unique way
they should go together in any one particular place. The important thing is that
the water is an inseparable part of the whole view. /(TRANNIES 22 and 23)/
BACK TO NATURE
The whole view has to be applied to the natural looking landscape and many of
the traditional styles of gardening too, and so where water is concerned the
plants you would expect to see near the water are the plants that would most
appreciate that situation. For these sorts of garden we are looking for effects
that carry us through to the spectacle of later on in the New Year. Many of them
would be lost at a more dazzling time of year, but they are appreciated more for
their singular performance when every other plant and flower seems to be
recuperating or closed shop from the severe elements. Phormiums and Berginia
doing the job of softening the formality of the water garden at Barnsley House
in winter)
For Autumnal effects amongst British indigenous shrubs: the
guelder rose (Viburnum opulus) will love a poolside situation and
light up the gloom with fine scarlet display of leaves and red fruit. The
Wayfaring tree, another Viburnum. (V. lantana)
can come up with various shades from copper to blue.
Japanese maples or acers love being near water, they seem
to adore their own reflection and reward you constantly for your thoughtfulness
in putting them there. In autumn all acers produce amazing colours, not all the
same colour and in the case of Acer griseum, the paper bark maple, or A.
pennsylvanicum, the snake bark maple, reveal astounding and distinctive
bark.
Liquidambers like it moist but well drained and if they
really like their situation in autumn they produce the closest thing in
vegetation to a firework display.
The Dogwoods (Cornus sanguinea) The
very similar C. sericea really come into their own in winter. There is an
Autumnal display of dark red leaves and shiny black berries but in the really
bare winter months they stand with their fresh new bark aflame in reds, yellows
and greens. There is nothing more enchanting than a poolside backdrop of
Cornus lit by a winter sunset against a stormy sky multiplied by its
reflection in the pond.
The Silver Birch (Betula pendula)
likes the poolside, although if you have a small to medium sized garden, a
cultivar that performs more in scale with the setting might be more appropriate.
B. p. Youngii is a small very weeping small tree, perhaps too weeping for
some tastes. B. p. Tristis is a compromise in that it is not quite so
flaccid, but my favourite is B. p. Dalecarlica, the Swedish Silver Birch,
with its cut leaves, white bark and delicate weeping stems. It is a tall and
elegant addition to any pool backdrop in any number, but grouped in threes.
For true winter flowers in the backdrop
there are the beautiful Witch Hazels (Hamamelis in several species), more
Viburnums (V. fragrans, V. bodnantense, V. tinus), the bush Honeysuckle (Lonicera
fragrans), the Mahonias (M. Charity is particularly splendid). These
winter flowering shrubs are partly renowned for their fragrance but none more so
than the daphnes (D. mezereum and D. odora). Insignificant
in flower but evident from their fragrance and evergreen leaves is the small
Sweet box or Christmas Box (Sarcoccoca confusa), also the large
Eleagnus x ebbingeii.
For bold colour in the leaves throughout
the harshest months, the evergreen Euonymus, the variegated privet (Ligustrum
ovaliu ‘Aureum’) and the sword leaved Phormiums in variegations of reds,
yellows or both.
Down on the ground for perennials next to the pond you can
use that persistent and reliable ground cover the Elephant Ears (Bergenia),
coming in lucent maroons, through pink to white. The Helleborus, the
Christmas rose, the black Hellebore and the Lenten rose provide opportunistic
foliage that carpets areas shady in summer areas. The spotty leaves of lungwort
(Pulmonaria saccharata) make a show before the blue to pink flowers.
These can fight it out with the primula that will form golden mounds in early
spring, or drumsticks of blue wherever you choose. In areas where thick leafy
ground cover is needed over damp areas, the rampant winter heliotrope (Petasites
fragrans) sends up sweet almond scented flowers before the leaves in
February. Most at home streamside, the Japanese cousins (Petasites japonicus
and p. j. giganticus) have larger more dramatic leaves and flowers.
But for those of you lucky enough to have
the soil in which they will flourish and protection from the rising sun, look no
further than the camellias. What more can you ask? Especially when you
can complement them with early rhododendrons. In January there is
Rhododendron mucronulatum, R. dauricum and R. parvifolium. These are
followed by R. Praecox in February, and so it goes on.
Don’t forget the bulbs and corms for the
clarion of the late winter wakeup announcement. Crocus can see you out at the
end of the autumn with only a months gap until they start again in early in the
new year. But winter aconites and the snowdrops and Narcissi can bear the brunt
of any harsh conditions more effectively. Cyclamen too, light up the dark under
shrubs and trees. In a nice protected south-facing rockery the little Iris
unguicularis makes a surprising display. The colchicums commonly known as
‘autumn crocus’ or ‘meadow saffron’, are in a separate family from crocus and
have many different forms. One in particular for the water gardener that is
almost a symbolic farewell to the water garden for that year is the beautiful
large mauve double flowered Colchicum speciosum ‘Waterlily’.
CHECK LIST FOR AUTUMN POND MAINTENANCE:
-
Remove fallen leaves. Net pond and stream.
-
Remove tender aquatics.
-
Clean pumps and raise them up to the marginal shelf level
so they only circulate surface water.
-
Only feed fish low protein food below water
temperatures10°C down to 7°C. Stop feed altogether at 7°C.
-
Maintain a hole in any ice that forms on the surface for
more than 3 days.
-
Cleanout any filtration system once the temperature
approaches freezing and close it down.
- Keep the pool
topped up especially in areas where there is a high water table. Treat any fresh
water with ‘pool conditioning’ chemicals.
Tony Roocroft and
Peter J May have combined their resources to provide the WWWGC (world wide water
gardening community) with the very best, up to date information on the
fascinating subjects of building ponds and pools, maintaining ponds, pond
filters, backyard waterfalls, pond plants, fish care and water quality and lots
of other exclusive water gardening and pondkeeping detail. This article was
written by Peter J May. Peter is the author of 5 water gardening books,
countless magazine articles, is the star of a pond building video and is a past
winner of the prestigious Gold Medal Award for water gardening at the Royal
Chelsea Flower Show. He is also a professional water gardens landscaper. We
would like to invite you to join our 2 weekly newsletter list
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