Ducks Unlimited NZ
Wednesday, 11 August 2021 22:52

Guide to planting a pond

Beech tree Beech tree

By John Dyer
Northern Gamebird Manager
Auckland Waikato Fish & Game Council

Nearly 50 years ago I started planting around my pond on a lifestyle block. There has been plenty of time since to observe and reflect on which trees and shrubs lived up to my expectations and what I might do differently if I started again. These same observations should be of use to anyone in the same situation.

Firstly, many people overplant a pond. Waterfowl like to warm themselves on a cold day and shade themselves on a hot day, much the same as humans.

Sunlight drives many of the food chains they are relying on and a pond that is too shaded will inhibit this.

One group of ponds I can think of epitomised this and the owner said they were better off before he planted them. Eventually the chainsaw came out and his pond cover was radically thinned, with a great deal of effort.

Sunlight is also important to maintain ground cover for ducks to nest in and a generally open pond is much more inviting and easier for ducks to fly in and out of. A gap cut in the trees can also direct them when they exit the pond.
If you are thinking about this, note where the sun comes from to shine on a pond and not just today but as it swings around the horizon at different times of the day or year.

If planting large trees, their shade would be better falling away from the pond and save the up-close stuff for shrubs.

For instance, flax flowers attract tūī and the small shiny seeds are eaten by pheasants. It is most useful when its leaves fall over the edge of the pond.

This provides good cover from hawks which will wait for ducklings to emerge to pick them all off. With lots of edge cover, the hawk is left watching the spot where the brood went in, while they more safely relocate further along.

When providing shade, it should be relatively open. If you look at ducks sunning themselves on a log that you have supported in place for them, (because  otherwise, like the iceberg, much of it will sink out of sight), you’ll notice they are all spaced in such a way that if they get a fright, they can easily take off without all their wings clashing. So trim back trunks at ground level to allow this quick getaway and leave higher branches to provide leafy shade. 

down toward the pen floor, it was every duck for itself as they raced to get their ‘manna from Heaven’. Pin oaks are another good variety to plant and I sometimes hear that “mine don’t fruit”. I thought this true of mine too until I put a game camera there to watch a trap. In the background I wondered why pheasants kept turning up.

A scratch in the pin oak leaf litter told me what I’d overlooked, the acorns were there all along but covered up. The birds certainly knew they were there.

Pin oaks are water tolerant (flooding, for instance), but not if it is year-round saturated.

Relocate that tree and watch it pull away.

Another scenario is when oaks line a farm drive. Passing vehicles crush and kibble the acorns and that makes them even more attractive for many waterfowl including pūkeko. Conversely, if your oak is planted in thick grass, the acorns are probably only really available to rats. Any tree needs to be fenced off from stock, of course, but you could perhaps put oaks on the edge of the fence and eventually overhanging it, so their acorns fall in the open.

Some oak species produce acorns that may be too large, though I have seen mallards carefully work turkey-oak acorns (the largest of acorns), until the point is facing outwards before they swallow it. Turkey oaks are one of those self-sterile species that will not fruit unless there are two of them.

Water oak (Quercus nigra) is a rare tree in New Zealand but there's one that I have collected seed from each year as it is a proven performer overseas. Same with water hickory (Carya aquatica).

Holm oaks are very salt tolerant, if you are near the coast. They have lots of useful sized acorns in April/May, especially if sourced from one parent tree by the main road at Pūkekohe Golf Club.

They are very water tolerant and I know of a number growing right on the Waikato River’s edge, being covered by each tide. Grey ducks, and I am sure mallards also, love the epiphytes (the flax-like plants) that grow on puriri branches.

If there is a branch growing over water with any gap in the epiphyte root mass that will support a nest, then it will be used year after year, provided you keep possums under control as they compete for these spaces.

How do the ducklings get down? They jump and regardless of the height of the fall, they bounce, pick themselves up and off they go. When the peeping from the nest stops, the mother duck assumes she has the lot and into the pond cover she takes them.

I have seen a grey teal gathering her brood this way under a nest box. They make a special quiet quack to call to those still in the nest.

Hearing this, a hawk straight away flew into the nearby tree and two pūkeko came running like the dinner gong had just been sounded.

This brings me to the next planting project, planting overhead cover in the water. Willows will establish, of course, but grey willow can be extremely invasive, and I can think of ponds, which used to be wonderful, but are now completely hidden by willows.

A similar species that is much better behaved is weeping willow. The cascading branches hanging in the water make good hawk cover, but be careful not to crowd a pond. One or two of this species on the edge might be ample.

All you need is a small pole to start it off. Make sure the pole is the right way up! If twisty willows are on sale at the nearby nursery, look away. I have never seen this species provide any benefit.

Swamp cypress is a tree that will actually grow in standing water and the “knees” it produces will make good places for ducks to climb out and roost on. It might tend to spread in the South Waikato downwards, but north of this it seems well mannered.

Climate will influence your choice of plants. For instance, I notice rowan trees in Rotorua thrive and are laden with fruit that birds love, but in Auckland and north, they’re misshapen and of little value.

Conversely, monkey apple trees (Acmena spp.) will thrive and produce abundant berries in Auckland and north that wood pigeons love, but frost will kill them off south of the Bombay Hills. Both rowan and monkey apples are now regarded as pest species, so there’s another thing to be mindful of.

Coprosma (karamu) is a native shrub that has orange berries, sometimes in profusion. If you have a green thumb, why not take cuttings from the most fruit laden examples you see. Everything from quail upwards likes Coprosma seeds, especially C. robusta.

Be careful that nurseries like to crossbreed new varieties and prostrate shrubs, which might be great in the garden, but will soon be overcome by weeds in your fenced-off pond area.

A native plant nursery is much more likely to have the uncorrupted parent plant.
To establish trees, talk to your friendly carpet outlet. What you’re wanting to do is to raid their skip for the old woollen (not nylon) carpets they’ve pulled up and thrown away.

You can quickly cut these into say 0.5-metre squares with a sharp skill-knife. Then cut a slot from one edge to slip around the tree truck.

If you have pūkeko, I strongly suggest you get a green plastic Poly Logic sleeve which you can put around the tree using three or four scrounged bamboo stakes. Pooks will walk past these and not realise the young tree is inside.

Otherwise, they are very likely to pull it out. Water and weed your trees well in their establishment years.

Thereafter they will look after themselves with perhaps a bit of pruning to get the good central bole you want. Don’t let the cattle in even for a short while. They will go for the trees before the grass and set you well back.

At any rate, if the grass is allowed to grow rank in spring, the ducks will have a much safer place to nest compared with a mowed or grazed pond paddock.

Likewise, be sure to set a Timms trap for possums as these can ruin a tree in just one night by breaking that tender young apex shoot.

A well planted pond is a joy to reflect on. Good luck.

Read 1594 times Last modified on Thursday, 19 August 2021 10:00

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