Changing Pond Water & Repotting Plants: An Update from my Wildlife Pond in Late Winter

An Update from my Wildlife Pond in Late Winter

Hello, and welcome to my wildlife pond in winter!  It feels funny saying ‘winter’, as the weather has been so mild this season that it already feels like spring.  Many of my aquatic plants are now coming into growth.  Last weekend, whilst I was observing all the new leafy growth on our aquatic plants and marvelling at the abundance of duckweed, I spotted a frog!  This was an extremely exciting and happy moment, as we’ve not seen a frog in our garden for years.  We decided to alter our weekend plans, so rather than enjoying the relaxing weekend we promised ourselves for the RSPB Big Garden Birdwatch, instead we’ve been busy working on the pond.  NB. This is the first time that we’ve gardened in our around the pond since my last update.

Spotting a Frog!

We spotted this large mature frog at the edge of our wildlife pond on the 29th January 2022. It has been ages since we last saw a frog, so this was a very exciting moment!

I couldn’t have been more excited to see this frog in amongst the Marsh Marigold (Caltha palustris) plants in the margins of our wildlife pond!  Just a few minutes later, we spotted the same frog in the narrow border around our pond as he made his way over to the stone cairn shelter we built at the back of the pond (in front of the fence) last year.  Look at this handsome fellow’s lovely flippers!  My heart leapt with happiness as I observed the frog patrolling his territory.

Ponds tend to be either frog ponds or newt ponds.  Our pond is most definitely a newt pond; we see far more newts than frogs.  Every year, we enjoy watching the baby newts (known as efts) developing in our pond.  The young newts often resemble silvery fishes as they swim in amongst the pond plants; visitors often tell us excitedly that they have spotted a fish!  Whenever I am near the pond I am always on the look out for newts.

Seeing this frog being active spurred us into action.  I had intended that we would remove any dead foliage on our aquatic plants in a couple of weeks’ time (at the earliest), but I didn’t want to take the chance of disturbing any newts or frogs as they become amorous in springtime, and so instead we relinquished our plans for a cosy weekend of relaxing and birdwatching in exchange for a damp weekend of pond action!  I’ll show you pictures of our pond work in progress in a moment, but first here are the pictures I’ve taken of the pond since my last update in the autumn.


A look down into and across my wildlife pond. The final flowers on my Myosotis scorpioides alba are blooming; there’s plenty of green, including duckweed! Pictured on the 21st October 2021.

Duckweed is quite an incredible group of aquatic plants!  These teeny tiny, miniature plants are quite mesmerising to look at, especially en masse.  Duckweed is often seen as a majority, as these aquatic plants reproduce at an astounding rate; they have the power to transform themselves from being just a tiny patch of green plants, barely noticeable with a cursory glance and often hidden in amongst the stems and leaves of other pond plants, into a carpet of fresh green that obscures the entire surface of the pond, within just a few weeks in summertime.

There are a few tricks you can use to avoid problems with duckweed…..

  • The first is to purchase bare root aquatic plants whenever possible and pot them up in fresh peat-free compost at home.
  • Quarantine new aquatic plants away from your pond (I use large tubs of water) for an extended period to ensure that all aquatic plants are free of duckweed before you introduce any new plants to your pond.
  • Duckweed is often transported to new ponds by birds that have spent time at a duckweed pond before heading off to visit another pond.  The duckweed is often temporarily attached to the birds’ feet or feathers, and washes off into the water of the next pond they visit.  Therefore, even if you start off with aquatic plants that are entirely free from duckweed, you are likely to still encounter this group of plants.  Accordingly, the most important thing of all is to regularly (and frequently) scoop out any duckweed you spot in your pond.  I use a net to remove duckweed from my pond.  It’s easy to dismiss a small amount of duckweed as insignificant or to postpone removing it until later, but the key is to take a net and scoot over the surface of the water at least once a week, more often if possible.
  • I was previously using a pond skimmer – the Oase AquaSkim 20, but I stopped using this product after discovering a dead newt trapped in the basket, which left me horrified!  Undoubtedly, my Oase pond skimmer was controlling duckweed very effectively indeed; as I never had a problem with duckweed whilst I was using the Oase AquaSkim 20.  However, for obvious reasons, I would never recommend this pond skimmer and have no wish to ever use it again.
I took this photo of our wildlife pond on the 23rd January 2022. There is a lot of duckweed in the pond, which I want to scoop out. Many of the aquatic plants growing in our wildlife pond have already begun to produce new growth.

It’s quite a challenge to remove duckweed from ponds that are planted with lots of aquatic plants.  In my pond, I find it difficult to skim the duckweed from the water, as there are so many aquatic plant stems on and below the surface of the water.  In wintertime, as the aquatic plants die back and a larger surface area becomes open it is far easier to clear duckweed, but it’s important to undertake this task at frequent, regular intervals throughout the year, and several times a week in summertime, when temperatures are warmer and duckweed reproduces fastest.

Duckweed can be composted.  Before adding any to your compost heap, double check that you haven’t accidentally gathered up any dragonfly larvae or other wildlife along with your duckweed.

Will I have removed all the duckweed from my pond?  No.  Sadly, there isn’t a chance that I’ve removed all the duckweed from my pond – to do this successfully I would have needed to have repotted all of my plants (I didn’t have nearly enough aquatic compost for this task) and cleared the sediment from the bottom of the pond.  I left the sediment alone, just incase any wildlife were hibernating in this area.  By changing the water and repotting a few aquatic plants I will have reduced the quantity of duckweed in our pond, but I certainly won’t have eliminated it.


The algae and blanket weed in my pond is far less noticeable over winter.  In late springtime or early summertime, algae ‘blooms’ and becomes very visible in ponds.  I am hoping that by draining out most of the pond water and replacing it with the rainwater I’ve collected in my water butts that the algae in my pond will reduce.  Although, this is far from guaranteed, as the pond water was syphoned out with a filter (a watering can rose taped over the end of the hosepipe) over the hose to avoid removing any pond life – I expect that by doing this I have kept hold of all the algae!  I have also left the sediment at the bottom of the pond, which will undoubtedly contain algae.  Will the changes I’ve made make any difference?  Only time will tell.

Once my pond water was changed, we added a dose of Ecopond Eco-friendly Barley-Bio Algae Control.  I will continue adding weekly treatments of Ecopond Eco-friendly Barley-Bio Algae Control, as this product is reputed to control algae.  I’m not aware of any improvements in the concentration of algae in my wildlife pond from using this product, but as it’s safe for wildlife and I’ve already paid for it, I’ve continued using it.  I also have purchase multiple packs of barley straw which I will add to the pond this weekend to help control the algae.

Aquatic Plants

Here’s a view of the other side of my wildlife pond, also taken on the 6th November 2021. My Water-Forget-Me-Not (Myosotis scorpioides alba) is still flowering! The red flowers in the foreground are Hylotelephium spectabile – regular garden plants that thrive in free-draining garden soil.

My aquatic plants are at a far more advanced stage of growth compared to this time last year.  I’ve allowed all their foliage to die back into the water and up until this weekend I hadn’t touched a single plant since before my last pond update in October 2021.  Here are some pictures I’ve taken of our pond since my last update…..

I took this picture of my wildlife pond on the 6th November 2021. The leaves of my aquatic plants are tinged with brown as the plants begin dying back for autumn.
A look round at the other side of my wildlife pond, as pictured on the 12th December 2021.
Here’s a look into my wildlife pond, as pictured on the 12th December 2021.
We’ve experienced a very mild winter, as a result, my aquatic plants have far more advanced growth than they had produced by the same time last year. Pictured on the 28th January 2022.
This is by far the earliest that I have ever seen Caltha palustris ‘Honeydew’ in bloom. Pictured on the 29th January 2022.

Climbing Plants

My ivy (Hedera helix) has been shimmering with the movement of the sparrows sheltering within its branches all winter.  Sparrows and blackbirds have devoured the ivy’s berries – this is such a wonderful plant for wildlife!

This rather lovely tangle of ivy (Hedera helix) and honeysuckle (Lonicera periclymenum) is still providing bees with pollen and nectar. Pictured on the 21st October 2021.

Border Plants

I’ve chosen to plant wildflowers and bee-friendly plants in the narrow border around my wildlife pond, but there is not much going on in winter, as these plants are at their peak earlier in spring and summertime. Pictured on the 21st October 2021.

I’ve left all of the herbaceous perennials around my pond to die back over winter.  Any leaves that have fallen in this area of my garden have been left.  Only the leaves from my garden path and patio have been swept up; these autumn leaves have been left in my garden borders for insects and wildlife.

This Asplenium scolopendrium fern is growing in the narrow border that surrounds my wildlife pond. Pictured on the 23rd January 2022.

The plants in and around my pond all look at their best in summertime; so there’s very little to see at the moment.  The area may look devoid of life, but that’s far from the case – many caterpillars have transformed themselves into chrysalis and will be hibernating ready to emerge as fully developed moths or butterflies when the weather is warmer.  Bees are overwintering in the nest boxes next to my pond.  There is life in the pond water and in and around the plants in the ivy hedge, in the wood in the log pile, and in the soil.

Removing Duckweed and Draining Pond Water

I took this picture on the 29th January 2022, in the midst of our attempt to clear out the majority of the algae and duckweed in our wildlife pond.

Last weekend we began our first attempt at reducing the algae and blanket weed in our wildlife pond.  For sometime now, I have been eager to repot some of my Marsh Marigolds (Caltha palustris) as the planters these aquatic plants are growing in leave the plants in a very direct and pointed straight line – something I particularly dislike.

We used two garden hoses to suction water out of the pond. To filter the water, we tied roses from our watering cans to the pond-side tips of the hose to ensure that no newts or dragonfly larvae will be accidentally removed from the pond.

I must first state that it is my husband who has done all the physical work here.  He is the one who has climbed into and out of the pond, moved the plants around and has been responsible for all of this activity.  We started by syphoning the water out of the pond; we filtered the water as it was syphoned to ensure that we were not literally sucking the life from our wildlife pond!

My aquatic plants are at a far more advanced stage of growth than at the same time last year. This Marsh Marigold (Caltha palustris) plant is pictured before it was repotted on the 29th January 2022.

We have two problems with our pond: algae (often known as blanket weed) and duckweed.  In the ideal world, I would have dearly loved to have repotted all of the aquatic plants with fresh compost to ensure that they were free of duckweed.  I didn’t have enough compost to do this and so I had to be selective in which plants were repotted.  I prioritised my Marsh Marigolds (Caltha palustris) as these plants were planted in a curved aquatic planter which is far less curved than I would like and has left the plants looking awkward instead of appearing at their best.

A closer look at one of my aquatic plants. In amongst the faded foliage there are hundreds of little duckweed plants! Pictured on the 29th January 2022.

I’ve moved my Flag Irises (Iris pseudacorus) into the curved planter and many of the Marsh Marigolds (Caltha palustris, Caltha plaustris ‘Honeydew’, and Caltha palustris alba) have now been moved into individual aquatic planters.  Aquatic planters are the best pots to use for planting pond plants.  I have a few free floating aquatic plants and a small number of pond plants that I’ve planted in planters made from material, but these plastic planters have so far been most successful for me.

Sadly, I didn’t have enough compost to repot all of my aquatic plants, but these Marsh Marigolds (Caltha Palustris) were potted into containers of peat-free compost. I lined the containers with hessian.

When I’m repotting aquatic plants, I start by rinsing out my planters and then lining my baskets with hessian – this natural lining helps the compost or soil stay in the basket until the plant’s roots get going and hold the whole thing together.  If you’re going to re-pot your own aquatic plants, ready-cut squares of hessian are available but it’s much more cost effective to purchase a roll of hessian.  As long as you keep the material indoors in the dry, the hessian will last you for future years.

I use bricks to raise my waterlilies up so they’re nearer the surface of the water. Pictured on the 30th January 2022.

Once the aquatic plants are re-potted, I usually sprinkle a light top dressing of pea sized gravel over the peat-free aquatic compost.  I don’t go mad with the pea-shingle, as this can make it more challenging for some aquatic plants’ new growth to emerge under the weight of a deep layer.  Large or heavy stones are best avoided for the same reason.  I save any stones I have to obscure the liner around the edge of my pond.

Here’s another view of my pond from the other side. The layer of sediment at the bottom of the pond was left alone as far as possible so as to protect any pond life. It looks very muddy! Pictured on the 30th January 2022.
Here’s a look at the Oase pond kit I use in my wildlife pond. This is an Oase AquaMax Eco Premium Pond Pump and an Oase Filtral 9000 UVC Pond Filter. I’ve used these products since my pond was first set up in March 2019.

My husband washed through our Oase Filtral 9000 UVC Pond Filter and our Oase AquaMax Eco Premium Pond Pump and removed as much of the blanket weed as he could from the pond.  He gently wiped over the exposed liner using a damp cloth (NB. no cleaning products were used).

We left all of the sediment untouched at the base of the pond – just in case anything was hibernating at the bottom of the pond.  The sediment will undoubtedly be chock-a-block with duckweed and algae, but the whole reason for setting this pond up was to help wildlife and removing this layer would have proved to be damaging for the creatures that have made this pond their home.

The majority of my aquatic plants are now back in the pond. I need it to rain so I can fill the pond up to the top of the liner.

Our pond was filled up as far as we could with all of the rainwater we’ve collected from our water butts.  However, as you can see, we still need more water!  From now on, no tap water will ever be added to this pond – we will only use rainwater.  If the algae and blanket weed return with vengeance then we have the option to repot all of the aquatic plants with fresh compost, and to clear out the sediment next year or another time.

Here’s a look at my wildlife pond filled up with all the water from my water butts! I need it to rain! Pictured on the 30th January 2022.

To see the next update from my wildlife pond and see how my plants develop and discover what wildlife I encounter in springtime, please click here.

For gardening advice for February, please click here.

For more articles about gardening for wildlife, please click here.

To see my plant pages and find information on growing a wide range of plants, please click here.

To see every update I’ve written about my wildlife pond, please click here.

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