Land plants (those planted in dirt) have a totally different root system than plants growing soil-less in water. One only has to wash the dirt off of plants growing in dirt and compare the root system to a plant that has never been planted in dirt to see the difference. As I mentioned in the post above all of our plants except lotus and lilies have never been grown in dirt, everything here is soil-less.
Many plants will have a difficult time adjusting to dirt when grown hydroponically and hydroponically plants will have a hard time adjusting to being grown in dirt. Bog lily, hibiscus, lobelia (cardinal and the blue) and canna are a few that have a particularly hard time. In our situation here we use a special fertilizer for hydroponically grown plants because we don't keep fish with the plants we sell. In a pond situation, plants grown soil-less in a pond (hydroponically) get what they need from the fish waste in the water.
What this means is you can not pull up some plants that are say, growing in your yard and put them in your pond and expect them to thrive soil-less. They will deteriorate quickly because they have a different type of root system than plants that were growing soil-less.
We used to grow all our plants in dirt in the greenhouse. Problem is it was a ton of work to plant them in dirt. Even back then before all of the shipping rates exploded it was expensive to ship a plant in dirt. And many states will not allow plants that are planted in dirt shipped into their states. California is a real stickler on that as is Arizona, and Florida. If caught, it could mean loss of your license, fines and or jail time. A whole new topic is certain plants are not allowed in certain states. If you see a plant and it says I can not ship it to your state, I cannot ship it there. Period. I am not willing to take the risk of getting caught. Yes I do tend to ramble...
Anyway, it was a lot of work for us to plant them in dirt, sell them and then wash all the dirt off to ship them more economically bare root. Even though we were not shipping as much as we do now, it was still very time consuming and a lot of effort.
After much thought and 40 years of commercial greenhouse growing Rich and I knew that there had to be a better way so we started growing pond plants hydroponically. To my knowledge we are the only growers who grow only soil-less. When we switched from dirt to water, we lost many plants. Some plants would not adapt to just water. But research and more experimenting taught use how to convert them.
Then there are other differences. Iris is a prime example. There are many species of iris. Bearded iris, Japanese iris are just two. They will not adapt to growing in a pond under any circumstances. The species of iris we sell are in the species of Louisiana iris and the only ones that will adapt to growing in water. Canna is the same way as is lobelia.
Finally I am not willing to share more information because many competitors would love to know just how we do it. And I get lots of emails asking and I just "decline" the email.
Please understand there are some plants that will do well in the conversion of dirt to water but there are many more that will not.
Have I totally confused you?