Good morning,

I have problem with my water lilies and have been searching for answers. I came across this page and looking very promising, so if you can provide guidance, suggestions, answers - that would be very helpful for me. And here is my story

4-5 years ago, I built an above group koi pond (attached picture) - roughly 700-800 gallons with 4 feet deep, 1 foot under ground and 3 above with full sunlight all day. I am from Indiana so during the winter I have 2 heaters with air pump submerged and 1 flowing heater to make sure the surface does not freeze. I had waterfall, water fountain with filter system. My water lilies for the first 2 years were beautiful and thick, leaves were big and covered almost the entire pond with many flowers + different colors, basically exactly what I hoped for.

However, last 2 years my lilies were very weak, leaves are tiny, and not much leaves or flowers. I checked the pots there were in and all good, I even changed the water. I read in other forums, they were talking about water lilies do not like water fountain and moving water much, so I got rid of my fountain, changed out my water filter, treat water with lilies treatment and yet - my water lilies are weak.

Any thoughts, suggestions?

Thanks

Water lilies come basically, hardy and tropical. Tropical lilies thrive in warm water temperatures. They awaken later in the spring and shut down earlier in the late summer or early fall. All of these shut down or slow down dates are water temperature controlled. I had a koi pond myself on Long Island for over 30 years and I never used tropical lilies due to that issue. Flower production and great growth was very limited. Plus, they should come inside for the winter.
I used hardy water lilies in my 1,500 gallon pond. I had them in large plastic pots. They would bloom much better from late May through late August.
They make fertilizer pellets and every spring I would use 2 per pot. I buried those slow release pellets in the soil.
But if the sunlight is just as strong now as it was when you built the pond, chances are it is temperature related.

I'm seeing a lot of juvenile leaves, which usually means lots of growth points sharing the rhizome's energy. Have you thinned the rhizomes since you planted them? Hardy water lilies should be growing along the surface of the planting media and splitting into multiple tips over time. As a rule of thumb, I remove half the rhizome growth points every year, and everything that exceeds the pot. Even with big pots I repot entirely at least every four years. Your mileage may vary, of course.

Do you fertilize? Water lilies need a lot of nutrients to perform. If you have rich, organic growing media and/or fish in the system you may have sustained nutrient input to your lilies. Otherwise, they aren't going to perform well without something like pond tabs.