Be careful, your watercress can block your waterfall and divert the water completely out of your pond. Keep an eye on it. Great pond. Nice healthy plants.

Larry is right, you should thin it out. Throw it in the pond. It will take root near shore and spread as a floating plant.

Water crest has survived winters in my pond, but my fish keep it from spreading too much.

Beautiful but true that it can divert water out and dry up the pond. A little thinning will be a good thing.

Nice pond!
The speed at which the watercress grew could be an indication of excess nutrients in the water. The watercress uses these, and therefore makes the overall water quality better. This is the principle of using it in a "vegetable filter".
The watercress also has a life cycle- it will stay reasonable under control until flowering time, when you will notice it having more growth above water level.
The lucky thing is that it is sooo easy to control. Either pull handfuls out, or cut it wil scissors if it is matted. If it's a wildlife pond, swish it around in the pond water to let pond creatures wash out, then leave it on the bank for the rest to escape back to the pond. It could have frog toad or newt babies amongst the leaves, so take care not to squish them. Leave a bit in the pond, and you'll feel back in control.
(Ps I have quite alot in my pond from the same source, but I'm leaving it a bit longer before I thin it because I still have newt larvae and tadpoles in the pond.

I'm in the Uk and have installed my own version of a skippy filter, and I have just put some watercress on the top, I love watercress and I was wondering if it would be safe to eat after careful washing in clean tap water?

Your lucky (or I'm very unlucky)I can't keep watercress in my pond. I've put it in my waterfall 7 times this year and everytime something eats it all the way down to the water level.
It's not the koi eating it because they can't get to it.

You can make cream of watercress soup too

ellekaye, I haven't eaten any of my watercress yet, but IMHO I can't see why it would be any different than watercress grown in fertilized soil or grown in irrigated and fertilized fields. Soil, air and water change manure to nutrients. The roots take on nutrients that grow the plants, the plants are edible.

No different than strawberries grown in irrigated, fertilized field or wild rice grown in a little slough filled with ducks. Man has been doing it for eons.

Nice pond....where's the fountain? ; )

I eat watercress from my pond. Washed, lightly boiled with a bit of soya sauce/olive oil and it goes down nicely. You have to make sure you only pick the newer growth unless you like fibre in your diet.

Do not eat if you have had to add any chemicals to control parasites in the past few months.

Plants are growing great in your pond!...Dave

My watercress in my new outdoor pond was growing profusely but is now dying off brown in the top. Can someone help. Everyone says there's is going great

Old thread here, but I'll throw out an idea. How hot has it been where you are? Watercress does not like the heat and will slow down or even die back. Once it cools off it will take off again.

Thank you. I live in Sydney and yes it is getting warmer. I don't know where this site originates. Is it o/s? I thought watercress like hot sun but I must be wrong.

I think Imj1221 is correct about heat or too much bright sun. Also, watercress much prefers flowing water.

Watercress definitely prefers the cooler weather. Mine will look like the original picture that headlines this post and as soon as the hot weather hits it dies way back. Once it cools down again it comes back with a vengeance.