I've been browsing online water lily stores and they only label their hardy plants as "Nymphaea" and trade names. What species are these? I'd really prefer native N. odorata, but it would be nice to have some more color than you get with the wild type.

s_a, I can't help you with the specific lilies, but here's an older site I use for lily ID's.

http://www.victoria-adventure.org/waterlilies/names/c-ce.htm

Unless you are into killing weeds stay away from native N. odorata. They will soon take over all your water less than 5ft-7ft deep depending on water clarity. Growing deeper in clearer water, plus the profusion of lilies tends to clear the water by using nutrients starving phytoplankton and allowing lilies to get more light deeper and grow deeper. If you plant the native white lilies you better save my list of herbicides in my separate post below of how to control the native whites. Native whites are cheap but troublesome that I learned many years ago.

Natives do two things hybrid lilies do not do. 1. Their seeds are fertile and sprout after flowers die and decompose. 2. Natives have abundant brittle rhizome tuber buds that break off, float to shore, and regrow where ever they rest. This is great if you want a lot of lilies fast. Not so good if don't what all your shallow water covered with lily leaves and stems.

To know more about a specific lily variety type the name into google. This should give you more information about a named lily. Worst case post the name in this thread and I will look it up for you.

Here are my basic guidelines if the seller gives you the spread info. Spread size also pretty closely relates to how deep they will grow from my extensive experience with them. The large lilies also tend to spread faster. My general rule is the white and yellow lilies as a group tend to grow deeper than the other colors. The changable lilies are almost all dwarf and small varieties.
Dwarf spread 1-3ft
Small 3-5ft
Medium 5-7ft
Large 8-12ft.

I noticed some heart shaped lilies just starting to come up in my pond . How do you kill them ?

If you have lilies with noticeable heart shaped leaves then I think you have spadderdock 'cow lily' Nuphar variegata small yellow roundish shaped flowers. I've seen them spread fast after they become well established into to 9-10-12ft of clear water and completely cover a 1 ac pond. The roots rhizomes can be 4" diameter and over easily 6-8+ft long. Real problems.

The best chemical control is using one of these herbicides: glyphosate, triclopyr, imazamox or 2-4D. Common glyphosate
compounds are Rodeo, Aquamaster, Eraser AQ, Touchdown Pro, and Shore Klear Plus. I like the Shore Klear Plus. Shore Klear Plus is glyphosate with an approved surfactant included. Maybe make the spray dilution a little on the concentrated side. You might want to let the patch develop an little more maturity as in June before adding the herbicide. This way the plants may be taking more food reserves and herbicide into the roots.

Renovate 3 is a triclopyr compound and Clearcast is an imazamox compound. Navigate and AquaKlear are 2-4D products.
Many aquatic herbicides have specific restrictions and use guidelines. Read product labels before using herbicides in your pond.

Wow mr.C thanks. These have white flowers that stay open most of the day then close. So I should let them grow till June before poisoning them?

Okay you probably have native white lilies. Can you post a close leaf picture or a photo link to them?. I would let the patch achieve some size and age with the first leaves enlarged rather than treating the first several emerged leaves. Maybe wait until they start flowering which is probably an indication the leaves are sending food to the 'roots'. You could treat the outermost leaves and leave the core group alive to provide some management control.

All I have is an iPhone so I can’t post pix until something changes. When they start blooming maybe I can email you the pix

Pat, look at this site and see if this is the lily you are talking about.
https://gobotany.nativeplanttrust.org/species/nymphaea/odorata/

Bill, you forgot about Habitat.

Esshup
The flowers look exactly like those, the leaves are still growing, so far they have expanded about the area of a truck hood so far....