I use 20-gallon (half barrel) pond liners I buy at Lowes. I've placed them in a kind of random pattern in a bed at one side of my backyard. I'm up to 8 and wish I had (no, make that NEED) more. I can plant other types of plants in between these liners. Four of the liners are small ponds (2 with water lilies and 2 with lotuses) and half are bog gardens (with 1 to 3 plants each). The super aggressive plants like horsetail rush or the irises you mentioned require a container to themselves.

I have my containers half buried. This keeps them from freezing but allows them to be at a better height for enjoyment/maintenance and keeps them from collecting runoff and grass clippings from the yard. I haven't put fish in any of mine yet, but believe the small ponds would work fine for a few small growing ones.

Thanks Brandon - are those type plants in some sort of planting mix, or do they just grow in the water? Also, do you have to change the water to keep it from getting stagnant? - I told you this would be stupid :-)

For the pond plants I use a mix of compost and garden soil. It's most likely not the best thing, but it's worked well for me so far. Surely some pond person can chime in and tell us what I should be using. I haven't changed the water so far, but would recommend doing a partial water change about twice per year. Here again, maybe a pond person can give more complete advise. Use mosquito dunks to keep the pesky varmits from becomming a problem.

So far as the bog plants go, the best mix for most bog plants is around 4 to 6 parts peat and 1 part course sand. I eyeball the percentage, but I think that's about what I use. I use pool filter sand from Home Depot. Be sure to use sand with an approximately neutral pH and the courser the better.

You can make a water garden in nearly any watertight container. I have kept water plants in everything from kiddie wading pools to tiny cup-sized planters. Sterilite storage boxes work, soup bowls work, whiskey barrels work. Anything that holds water, essentially.

Water plants tend to do best is a heavy, clay-ey medium. Good old Tennessee clay works. Put gravel on top to help decrease clouding of the water (or not -- I usually don't). True bog plants (pitcher plants and so on) need peat, but many "bog" plants -- various plants that tolerate or thrive in wet conditions -- will do fine in many different mixes.

The iris you got -- yellow flag, aka Iris pseudacorus (sometimes also called Louisiana iris, but it isn't truly one of the Louisiana irises) -- will grow as a true water plant, a bog plant, or out in the garden. Just make sure it gets as much sun as possible for maximum blooming.

The only times you really need to worry about water changes, IMHO, are in the fall if the water gets fouled by too many fallen leaves, and in the spring when things are just getting started. Otherwise, just top it off as necessary. And have fun!

As promised at the swap, I've got some pictures up of my water gardens. I really enjoy mine.
Some things I planted in "real" water plant soil, others in Moisture max, others in what Ione brought them in. They seem to be very forgiving. I did put pebbles in the bottom of all my containers and I put them on top of the plants or mix them into the soil. I get those for $2 a bag at Kmart.
I want to get a couple of water gardens put in the back patio garden next year. I've got some fountains and drippers to go in the ones in the front as soon as I get electricity out there. It's at the top of the project list. I don't get enough sun to run solar.
In the meantime, I use mosquito dunks to keep the biters away.
As long as I was doing photos, I stuck on some of the Night Blooming Jasmine in bloom and of the much-malinged Bradford Pears that do well here in the condo complex.

Here is a link that might be useful: Madmouser's Water Gardens

Madmouser, do you live at the Palisades on Gleason Rd.?

Yes. You live there or visit there?

Oh My! I am in love with your garden. That is absolutely gorgeous, I truly love it, and unfortunately you've given me LOTS of ideas. Thanks to all of you for the info. Thanks Madmouser for sharing the photos. Maybe I'll be able to trade for some plants at the spring swap :-)

Frances

Hey Madmouser, are you sure those are Bradford Pears? It's hard to see a lot of branching detail in the picture, but from what I can see, they don't look like they have typical Bradford Pear branching habit. I'm wondering if maybe they are another type of ornamental pear tree.

Typical Bradford Pears that size would have a very congested branching pattern on the trunk and would likely at least show signs of branch crotch splitting. Do these have the typical foul Bradford Pear smell when in bloom?

BTW, I agree with Frances, your garden is very pretty!

a little off topic, but Madmouser .... could you post your cookie recipe????? I'd like to try those for the holidays, and of course will have to practice a bit before then :-)

No, not sure they're Bradford Pears at all. Just know they're beautiful when they bloom. I don't notice any scent at all. They have some sticky sap in the spring that gets on cars and small hard round green fruits that the birds eat. The leaves turn red in the fall. They do drop twigs a lot but the gardeners/maintenance folks have to deal with those.
I'll send out a pear bloom alert this spring when they bloom.
Thanks for the comments on my gardens. I really do enjoy them. So much easier than planting stuff in the ground. Best thing I did was have Lowes deliver 10 big bags of potting soil and three half-barrels. Those are what the Elephant Ears are in. That really helped me expand. Plus people leave me orphaned pots and plants when they move. I find them on my doorstep with a note.
I'll give you a link to the cookie recipe I used for the swap. I couldn't find the one I had originally -- it's a newspaper cutting stuck in a book somewhere -- but this is similar. Do use the foil cupcake things. The paper ones stick. And real butter. They stay rounder if you bake them in muffin tins. I just used the foil cups on a baking sheet and they got sort of freeform. They are good.

Here is a link that might be useful: Chocolate Chip Cookie Cupcakes

"Plus people leave me orphaned pots and plants when they move. I find them on my doorstep with a note. "

That's so cute! :-D