By Heather M. Rosa
As published in Aqua News September/October 1996
A Publication of the Minnesota Aquarium Society
I'm not sure if my interest in having a pond stems more from my interest in goldfish and koi or from my love since childhood for water lilies. Over several years, my ponds have grown from an $8 child's wading pool to a stock tank to a 1500 gallon (Or thereabouts, I haven't tried actually "counting" the gallons, since it's too much work and I'm sure to lose my place around 967 and have to start over.) dug in, lined, terraced, multileveled, filtered, fountained, landscaped, backyard work-in-process showpiece. I have tried several varieties of lilies in several styles of pond, with varying success, and have more ideas on how to do it better this year.
Let's start with the intimidation factor. You know, anything that showy has to be terribly difficult and expensive, right? That was my starting assumption. Last year, I grew one of my lilies in a 5-gallon sitting in the vegetable garden. It was "supposed" to go into the pond, but somehow life just happened, and I never quite got around to it.
So if it's not that difficult, just what do they really need? Obviously: water for a start. The 5-gallon bucket wasn't optimal, because the leaves should spread out more, so perhaps a half whiskey barrel, leak proof or lined, would be minimal. Plan on: 1-1/2 to 2 foot water depth, 1-2 foot radius for per lily; depending on the lilies’ variety and size. Still water is better than splashing, since lilies don't like water on top of the leaves once they emerge. (I know, it's a fine time for them to get picky, but they do and that's that.) In a bigger pond with a fountain, try to put the fountain to one side opposite the lilies.
When you buy commercially packaged lilies, there should be instructions for the depth of the water over the soil level. This should not be confused with the total water depth. That is because the second thing a lily needs is heavy soil in a pot. The soil can come straight from your yard, presuming you haven't gone gaga with pesticides. Also, presuming your yard isn't a 12th story balcony. If you can't dig soil, try a mix of sand and sterilized compost. It should never be potting soil, and if you buy one already potted in such a mix, repot it before it gets near your pond! This is because potting soil contains perlite. It is white. It floats. And if it doesn't give any fish you might have indigestion when they sample their new snack, it will be an unsightly addition to the pond surface. Yes, you can scoop and net it out, but it magically breeds every time you turn your back, and bobs on the water laughing at you. All summer.
The pot should be shallow and wide, size depending on the size of the root. Many books recommend mesh pots. I find that solid with a few small holes in the bottom works better than mesh to keep soil in place against water currents and fish activity. A smooth pot bottom will do the least damage to a pond liner, but a piece of carpet or extra pond liner under the pot can protect your pond from punctures or wear. Fill your pot to an inch or two from the top with soil, and have a supply of small rocks or pebbles to cover the dirt after planting to keep currents and fish from uprooting your lily, more on how to plant your lily later.
If your water is deeper that what your plant needs, find a pedestal of the right height that won't damage your pond liner or trap or damage fish. I am hesitant to use milk crates, though the height would be perfect in my pond, because I have fish just the right size to ruin long fins trying to swim through. Cement blocks wrapped in carpet or pond liner scraps to protect fish, and spaced to support a board was one solution. Thought and imagination supply more. The big pond was dug with ledges of different heights on the sides for different plants' needs.
The last big requirement for water lilies is food. Some they get from the soil and some from pond fertilizer. (In small amounts unless you want your water solid green, so thick you can't see why your fish's gills aren't clogged. You can't see your fish's gills at all, or your fish.) Most of the food, however, comes from sunlight. All day sun is great, if you have such a spot for your pond. Half a day is minimal. Your lilies will live, but bloom count and size will decrease. And remember, if all day sun is more than you want for your fish for maintaining a cool temperature, the lily pads will provide shade.
Your lily will have three parts to it. First is the rhizome, looking something like a cross between a log-section and a potato, but somewhat scaly. Depending on variety, and how cheap the grower was, its size can vary from a finger joint on up to about a 2" diameter. Length increases with age, but I've usually gotten them about 3" long if they're going to bloom the first year. If the rhizome is all you see, you're going to have a challenge planting your lily.
The second part of your lily is roots. These extend to the side and below the rhizome as it lies horizontally. Some growers prune them off, presumably to save costs storing and shipping, but hopefully you have at least some remaining. The lily will grow anyway, but it will be slower. The third part is the leaves. These grow out of nodes on the top of the rhizome, and are usually very tiny when you first get your plant. If it is already potted, or the bare-root rhizome has been warm a few weeks, they may have grown significantly.
Plant your lily exactly as you would a bearded iris. (No iris? Well, here's how to plant both, in case you ever need to know about iris.) The rhizome is set horizontally on the soil surface, not under the soil, with the roots spread out through the soil, and the leaves pointing up. (This is where the iris analogy ends.) Spread small rocks over the soil surface, but not over the rhizome itself. Before placing my pot in the pond, I immerse it in a bucket or larger container of water. This way I know if my rhizome is anchored firmly, and can skim off anything floating up out of the soil before it reaches the pond.
I did have one lily rhizome that arrived minus roots and any visible nodes, and I couldn't decide which way to plant it. I arbitrarily picked an up and a down, stuck it in the pot that way, and waited, and waited. And rechecked, and waited. About the 1st of August, a tiny leaf made it to the surface, and by summer's end, there were 9 tiny leaves. The rhizome accommodated itself to its topsy-turvy fate, but can't be said to have thrived. (I have made a note never to buy from that grower again.)
Note the rhizome will grow lengthwise during the summer, so there should be room between it and the edge of the pot. Also, rocks should be too big for fish to move, but small enough to give way before the plant.
Very little care is needed during the summer. Fertilizer may be given sparingly, but can encourage algae, as noted earlier. If fish are in the pond, their wastes provide nutrients. Dead blossoms and leaves should be clipped to encourage new growth, and to keep from fouling the water. If fish are large and active, e.g., spawning, you should probably check regularly that the roots are properly covered. Koi particularly find them a tasty treat.
You can now sit back, relax, and enjoy the show. (However, you may find yourself spending a lot of time once your lilies start blooming entertaining neighbors and friends who "just dropped by", setting up picnic tables, mixing ice tea, and tending the grill...)
Hardy lilies can stay in the pond until the 1st ice forms, but I pull them out sooner. It is such a wet, cold, beastly job anyway, usually involving partially draining and climbing into the pond, so why put it off until you can risk frostbite?
Once the buckets are out and draining, I cut off all leaves but the tiny ones at the node, and send them to the compost pile. The rocks are removed and saved for next year. Root cutting is often required after rinsing away the soil in clean warm water (for my comfort, not the lilies). I'll leave a few on the rhizome for next year's head start. The soil gets thrown back in the garden; I'll dig from a different spot next year. It's a little like crop rotation, and for the same reasons.
What I have left is a rhizome with a small mass of roots, and leaf nodes. Yes, nodes, plural. Next spring I can decide to separate these by cutting vertically through the rhizome between the nodes for new plants. Or, I can leave the longer rhizome intact for a fuller lily, for as many years as I have pots and pond large enough for them. (Not to mention somebody with arms and back strong enough to heft pots of wet soil and rocks!)
Some lily rhizomes will also have formed branches or buds that can easily be separated for new plants. These will often be small and without roots, and will probably take an extra year to bloom.
Now, if I was smart during this cleaning process, I remembered which lilies were which color and variety. For the sake of argument, let's pretend I was smart. Then they are sorted by variety, put in plastic zipper bags with “slightly” damp peat moss, labeled, and stored in a bin in my refrigerator all winter. The peat moss and sealable bag keep the moister level necessary fro wintering. The peat is also fairly acid, and may help prevent rot and fungus, though I check for those in the spring and cut out any I find, which I haven't, yet; so it probably works. The refrigerator keeps them dormant for a time, which they need, since you bought hardy and not tropical varieties. (You did, didn't you? It's supposed to say in the catalogue, or on the tag in the garden center, too late now.)
Now, assuming that your refrigerator didn't accidentally freeze them, and nobody got grossed out by having novelty non-food items in the refrigerator and threw them out, or better yet, decided to stir-fry them, you can start the whole process again in the spring as soon as the ice is off the pond.