Ponds Part 3 - Plants

We showed why we believe that everyone should have a pond and how anyone can make such a feature in their own back yard in the previous parts to this series. This time I would like to give you a few ideas on what to plant around as well as into your pond. The plants I mention here are by no means a complete list, nor are they essential.

Aquatic plants

Aquatic plants are plants that live all or most of their lives in water. Some are sitting at the edge of the pond and dip their roots into the water just at the bank, some are completely submerged and others float around on top of the surface. Before I start mentioning individual plants I would like to say that there is no such thing as an invasive plant. There are opportunistic plants and some of them might be unwanted, but just because we don't want them in our pond does not make them a pest. I think people automatically label anything that isn't deliberatly put at its place in the garden as a pest. According to one of my neighbours, nearly everything is a pest. Bedstraw, alders, dogwood, you name it, it's a pest....apparently. Of course that is nonsense.To show you what I mean I will start with a very common water plant, that is often seen as an invasive pest, the common duckweed.

Pic 1 Duckweed Lemnoideae sp.

Duckweed floats on top of the water and multiplies with an extreme speed. Once it takes hold, it can completely cover the surface area of your pond within mere days. A lot of the time, much to the demise of the owner of the pond. But here is why you shouldn't be upset about it. Duckweed is both an indicator of contaminated water and a cleaner. A clear and healthy pond does not support the growth of duckweed due to the lack in necessary nutrients. Duckweed is often found in still waters that are influenced by pollution. The good thing about it, as I mentioned is that the duckweed feeds on the origin of the pollution and in doing so, can remove unwanted chemicals (I use the term in it's actual sense, not as something describing man-made pollution). If those chemicals are not replaced, by continuous pollution for example, the pond will get cleaner and in time the duckweed will recede as there is nothing left to feed on, leaving organic matter behind to fuel the system. So as you can see this "pest" is actually quite useful and I have heard of constructed wetlands that utilise duckweed to clean the water.

If you really don't like the look of the duckweed and would rather get rid of it, you can simply scoop it off the surface using a large net and use it as mulch or compost. This counts for any aquatic plants by the way. The production of biomass is so high in the aquatic environment that you will, sooner or later, have to resort to the removal of some plants and using them as fertiliser is the best way to deal with the "problem".

Aquatic plants, including submerged, produce oxygen during the day by converting dissolved CO2 and water into energy and O2 just like our terrestrial plants do. This is how water is oxygenated in the natural systems and how the plants help support fish and other animals to live in the water. So even though you don't see a lot of the the submersible plants as they are often completely submerged, it really helps keep your pond healthy to introduce a certain amount of them. One of those plants is Elodea canadensis also called Pondweed. The only time you can see anything of this plant on the surface is when it is flowering. It has a tiny white flower that is attached to a fine thread connecting it with the rest of the plant.

Pic 2 Elodea sp.

There are numerous plants that produce high amounts of oxygen and those are the plants that you should establish in your pond in the beginning, BEFORE stocking any fish. But I will probably write another post on how to stock fish into your pond later.

Then of course there are the surface living plants. The most commonly known would be the water lilies (Nymphaeaceae sp.). I don't think I have to explain much about water lilies. I never met anyone who didn't know a water lily when they saw one and I also never met anyone who didn't like the look of water lilies (although I am sure there are some people). Water lilies are also very efficient in cleaning your water. I haven't got any water lilies in my pond yet. The reason being that I found them far to expensive to buy (our local garden center sells them for $40 a piece. and they weren't in good condition). There is a lake that I frequently visit during the fishing season, which has a lot of water lilies, but you wouldn't believe how hard it is to unearth one of those buggers.

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At this stage I would have to put out a disclaimer. BE VERY CAREFUL WHEN TAKING AQUATIC PLANTS FROM THE WILD!

First of all you can introduce diseases and parasites into your pond which is bad in any case. But if you decide to take wild plants please make sure that they are not an endangered species and that you don't cause any irreparable damage to the ecosystem you are removing the plants from. I love Jack-in-the-pulpits and really wanted some for my pond. During a fishing trip I came across a truly amazing specimen which was at least 60 cm in diameter. But the population of those plants are in decline and they are better left where they are. I bought mine from a wonderful person who lives in the city close to us and specialises in native and endangered plants (http://tinyurl.com/aly8tgm). So please be responsible about taking wild plants. 

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Another aquatic plant that actually volunteered itself in our pond is pickerel weed. Pickerel weed is very prominent around New Brunswick. I am not sure yet, whether pickerel weed might become a problem in our pond. Judging from the speed it took hold it might become necessary to remove it at some point. But it does look nice and for now it is restrained to the edge where the water is shallow. 

Edge plants

Along the edge of the pond is where the biomass accumulation becomes most apparent. Here you can see all the plants that are competing for space and form symbiosis with each other. 

I already mentioned the Jack-in-the-pulpit plant. Jack-in-the-pulpit is a carnivorous plant and a kind of pitcher plant. It has pitcher-like leaf formations that contain a liquid that attracts insects. When an insect lands on the slippery leaf it often falls into the liquid and is unable to get back out. The liquid is actually the digestive juice of the plant and the trapped insects are slowly digested to nourish the plant. The upside for us humans of course are less bugs (less mosquitoes, yesssss....). Although I think our native frog population does most of that work already. But I will discuss the fauna diversity of the pond in the next post.

We also brought in some water cress which has really nice white small flowers and grows all around a large part of the banks by now. Water cress is edible, although I have not yet tried it.

Pic 3 Water cress Nasturtium officinalis

We also introduced American Sweet Flag (Acorus americanus). Sweetflag is a native plant with edible fruits that look quite phallus-like. Again, I haven't tried them yet. Care should be taken when eating Sweet Flag. Some strains produce a procarcinogenic compound called beta-asarone. The strains native to North America though seem to be void of this compound.  Be also careful not to confuse this plant with the very similar looking Blue Flag. As usual, when it comes to eating plants from the garden or the wild, don't eat anything that you can't 100% identify.

Both Blue Flag and Sweet Flag belong to the sedges or rushes. In general those plants have a tremendous ability to clean the water they contact with their roots. Rushes are in fact so good at cleaning water that they are heavily used in constructed wetlands for water purification purposes. Depending on the resting time of the water, a combination of rushes and charcoal can turn even black water into something that is fit for consumption. In order to do this properly you really need to know what you are doing. Constructed wetlands are a complete topic on their own and I might start a series about how to construct one later. The internet is also full of information about those features.

As mentioned in part 2 of this series we have a lot of bullrushes and cattails in the area where we dug the pond and those plants are still very very prominent. I recall a lecture from Bill Mollison, the founder of Permaculture, where he urges anyone to get rid of any cattails along the pond. This is due to the enormous opportunistic properties of the plant. But for now I leave them be. And the fresh shoots taste and smell a lot like cucumber. In fact every part of the cat tail is edible at different times of the year.

Pic 4 Cattail with seedpod opened

There are many plants I still want to incorporate into the system. Water is the best biomass accumulator and some of the fastest growing plants are aquatic plants. While plants like kang kong (Ipomoea aquatica, aka water spinach) do not grow in our climate, other edibles do. One candidate high on my list is water chestnut. The production of edible nuts is supposed to be very prolific. 

Surrounding the pond

Going a little bit further away from the pond's edge is where we started to plant several other shrubs and trees. On the northside of the pond (which is the start of the slope we built with the excess dirt described in part 2) we planted a plum and a cherry tree. Both of those trees are cold-hardy types and they should be able to cope with the winters here

Pic 5 Afton planting our Cherry tree (Montmorency)

A pond or lake can be utilised to extend your growing season for fruit bearing trees and bushes. The large amount of water acts as a heat sink (in the hot times) and as a sun reflector (meaning the suns rays have a stronger affect in the cold times). Sepp Holzer, a Permaculture farmer in Austria, has created multiple microclimates using ponds at his farm, that allow him to even grow citrus fruits at altitudes higher than 1,000 m above sea level.

Furthermore, around the pond we planted blueberry, blackberry, raspberry and haskap berry bushes that all benefit from both the constant supply of water and the additional climate buffering properties of the pond and we benefit from the healthy and delicious fruits and berries that these plants produce. Win-win I say.

As I said before, there are so many plants you can incorporate into your pond and it helps to read up on them all to see how you can build guilds of plants that interact positively with each other and their environment.  So let your imagination run free and happy planting.

Ponds Part 2 - Technical aspects

Wow this took a while, I apologise for the delay, but sometimes life just gets in the way. So without further ado, here is part 2 of the pond series.

The benefits of incorporating a water feature like a pond have been detailed in the last post about this topic. In this post I would like to outline how we went about to design and "build" our pond.

On our 1 acre site a good 20% was swamp or wetland. This part had been left completely to itself with bulrushes and cattails growing up to 6 feet high. Frogs resident in this wetland formed a background of noise in the spring time, but there was no visible water....until you stepped into the thicket of rushes and you realised that you sank past your ankles.

Pic 1 The morning of the dig, facing West April 2011

We had each always wanted a pond, and this part of the property looked perfect. We started designing a rough outline and thought about how deep we wanted to make it. Winters here can be really cold and in order to stock the pond with any fish at all it should be at least 6 feet or better 8 feet deep to allow room for survival.

Edge is an important aspect in Permaculture as any edge in nature is always the most biodiverse area in a system. You want to increase your edge, or lengthen your bank, as much as possible and this helps determine the population of fish you can stock, the variety and quantity of edge plants etc etc. Edge can be greatly increased by adding curves and features to the design of a pond so in this respect, a round pond is the worst thing you could do.

We decided to have a random kidney type shape.

The ground on our site is full of blue clay. Once you get to a couple of feet deep that is all you get. Clay is perfect to dig a pond that is able to retain its water without a liner. Therefore we planned not to use a liner but have a natural sealed bottom. We also planned on having ducks in the pond at a later stage and ducks can aid the sealing of the bottom with their poop.

So after all this planning it was time to make a phone call to a contractor that lives just up the road from us. After all, I did not want to shovel the size of my pond by hand.

A short word about contractors for earth moving. Running an excavator or Bulldozer is one thing, but operating an excavator or bulldozer properly and efficiently is another. A pond to some is just a hole in the ground filled with water, and to others there are a lot of factors to consider.

Our earth mover, Tom Egers, is one of those artists with an excavator. Once in the machine it is hard to tell where man ends and machine begins. Tom had built many ponds in his life and offered valuable advice on how we can build our pond and be able to enjoy it for a long time.

The first negative news that Tom relayed to us was that a depth of 8 feet could be hard to achieve. Apparently dirt falls at a 1:1 ratio. Which means for every foot depth you need to go out by one foot. unfortunately we would be getting quite close to the property line and making the walls steeper would result in earth sliding down until that 1:1 ratio is reached. Meaning our pond would "run" into our neighbours property with time.

We settled on a depth of 6 feet and have to trust in global warming for fish to survive...eh yes.

We knew that the ground is packed clay on most parts of our property, but it can always happen that you hit layers of sand, or even rock. If you are not sure what to expect, dig a test trench. You can do that with a shovel and several hours of work. It may seem like a pain in the back, but it can save you from disappointment.

Digging a pond will bring up a LOT of dirt. It is advisable to plan ahead for all the excess dirt that will be created in the process. You can either have it hauled away or use it. Hauling dirt away from you property is costly, you will have to pay the truck and driver, using it is a better solution. Our pond is situated at a low point on our property and the drop off is rather steep. I had therefore planned to use the dirt to even out the drop off into a slope that can be used for growing food or trees and have a gentle transition into the pond. At this point it should be noted that in order to grow food or trees topsoil is of utmost importance. Generally earthmovers will scrap of the topsoil and put it aside before commencing with the actual excavation. Make sure they know to do this before you let them on your property. This topsoil can then be spread over the parts where you want to establish your vegetation. Good topsoil is worth it's weight in gold, so don't waste it.

Once all these decisions had been made, and all the planning was done, it was time to get down to business.

Oh, I might have to mention another thing. We got an estimate on the cost from our earthmover. This is something that is very important. But, it is always hard to estimate exactly how much time is needed to finish the work and estimates mean nothing if the earthmover does not have a good idea about how long it will take him/her to complete the job. Tom Egers is well known in our community and one thing that we have heard from many other people is that the estimates he gives his customers are never too low. Meaning, you will never pay more than what you are planning with. In my opinion this is a very very important aspect. I have been cheated in the past and that does not only leave a bitter taste in your mouth, but also can severely upset your financial planning. Make sure that the estimates you get are accurate. This means to go out and get some opinions about the people that will be working for you. Maybe talk to other customers of theirs in the past. Tell the earthmover to give you a "maximum cost". I rather calculate with a higher cost and then have money left over than the other way around. Once the digging starts you will not be able to stop it. Or better: you don't want to stop it.

So, now we can begin. Dirt ahoy.

Pic 2: Making the borders

Once the digging has started there is little for you to do. Our earthmover did insist that at least one of us is present at any given time, as he might have to make some amendments during the work and that is pretty much all you are there for.

Pic 3 Showing the scale, Nils is 6 ft tall. We can't stand here anymore....

After everything was done, the only thing we still had to do is built the dam for our overflow. We used some of the clay that was unearthed during the excavation and so far the dam has held and the overflow is working perfectly.

When designing an overflow it is important to try to slow the water down to prevent erosion. Making the overflow too narrow and too steep will cause the water to rush over in a large rain event and take with it a little bit of earth and soil every time. After a while the overflow will break down. It does pay to grow some plants with good fine root structures right on top of the overflow and possible cover the top with some stones.

Pic 4: North-East view of our summer pond and densely growing slope

So I hope to have given you some ideas on how to design your pond and maybe this year you will decide to incorporate such a multi functional and beautiful piece of landscaping into your own site.

Since it is mid winter (the coldest day of the year with -40C with the windchill) as I am writing this I will now lace up my skates and enjoy some of that good Canadian culture....on my private skating rink. 

Pic. 5 Fun

Yet another function of a pond in your backyard.