Thursday, November 18, 2010

Stock tanks for bamboo

In our back yard we have four bay trees (Laurus nobilis) that were planted when the house was built in 1990. Now the trees are 30-40 ft. tall and shade a large part of our back yard—not to mention provide us with a never-ending supply of bay leaves. If anybody in our area needs bay leaves for cooking or crafts, drop by. You can have as many as you like!

Unfortunately, the root system of bay trees is shallow and extensive, so planting under them has been an exercise in futility and frustration. Digging is hard enough since the roots form a dense mat, but almost anything we planted over the years ended up dying since the trees suck up all the moisture and nutrients. The few plants that have survived the longest include a cast-iron plant (Aspidistra elatior), which I believe is truly indestructible, a Japanese holly fern (Cyrtomium falcatum) and a clivia (Clivia miniata). Since this is a such a shady area, it would be ideal for ferns, astilbes, hostas and the like, but these plants like rich soil and moisture and would never be able to compete with the voracious roots of the bay trees.

In the last few years we’ve put pots of different shapes and sizes under the bay trees. We’ve had pots with just one plant each, and communal pots with several plants that complemented each other. Some of these arrangements worked well, others not so much. As we learned, container gardening requires a great deal more attention, and plants need to be fussed over or swapped out a lot more often than they would in the ground. As much as I like to putter around in the yard, I eventually got tired of the constant care these pots seemed to need.

So the inevitable happened: The artfully designed arrangements went bye-bye, to be replaced with bamboo such as Fargesia dracocephela ‘Rufa’, Phyllostachys bambusoides 'Castillon' and Hibanobambusa tranquillans 'Shiroshima'. I love the lush green effect these bamboos provide.

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Back fence under bay trees before stock tanks

Now we’re about to take the use of containerized bamboos even further.

A few days ago we bought two 2x2x6 ft. stock tanks made of galvanized steel. These tanks are typically used as watering troughs for cattle and horses but they make great containers for bamboos as well. I understand that many people think they’re too industrial-looking (“ugly” would be another word) but personally I think they’re quite attractive.

Being made to withstand harsh outdoor conditions, these tanks should last for many years. We’ve used a small 2 ft. round tank as a planter for a long time, and it was well used even when it came into our possession.

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Stock tanks to be used for bamboo

Since these tanks are quite large (they hold 180 gallons of water), they require quite a bit of soil: about 1.8 cubic yards. That’s the equivalent of 24 smaller (1 cu.ft.) or 12 larger (2 cu.ft.) bags of potting soil per container. Buying this much soil in individual bags is much too expensive so we opted for the bulk delivery of a high-quality soil mix as well as some gravel to put in the bottom of the tanks for drainage.

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Soil and gravel in our driveway

The first step was to level the two areas under the bay trees where the tanks would go. My wife—bless her soul—did most of the prep work. We placed six concrete stepping stones on the ground to keep the tanks elevated by few inches.

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Stepping stones to keep tanks off the ground

Next I punched a series of small drain holes along the front of each tank. I chose to do this in the front rather than in the back because I want to monitor the holes for stray rhizomes that might eventually want to escape. Then we added about 3 inches of pea gravel to create a drainage zone at the bottom of each tank.

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Gravel layer

On top of the gravel we put weed cloth to keep the soil separate from the gravel, and hopefully most of the roots in the soil layer. My wife and I were going back and forth between using weed cloth and leaving it out, so most likely it wouldn’t have mattered if we hadn’t used it. (If you have any experience with using weed cloth in containers—positive or negative—please leave a comment at the bottom of this page.)

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Weed cloth on top of gravel layer

The final step was straightforward enough: fill up each tank with soil. This required a number of trips with our trusty garden wagon, and a great deal of shoveling, but eventually both tanks were filled.

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Left stock tank after filling it with soil

I added a layer of composted steer manure on the top to give the soil even more zing even though it already has all kinds of goodies in it: mushroom compost, chicken manure and who knows what else. This soil is dreamy: loose, crumbly and fertile-looking. If I were a plant, I’d want nothing more than to put down roots in this soil.

If you live in the Davis/Woodland/West Sacramento area and are wondering where the soil came from: We bought it at our favorite place for landscaping supplies, Dixon Landscape Materials. We cannot recommend them highly enough. They have a large selection at reasonable prices, and they are super nice to work with.

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Right stock tank after filling it with soil

The final—and most important step—is to plant the bamboo. That will have to wait for another day. I don’t even have the plants yet! I will pick them up from Bamboo Sourcery in Sebastopol the week after Thanksgiving.

UPDATE 12/4/10: The stock tanks have now been planted. Click here to read about it.

9 comments:

  1. You've discovered the magic of photo stitching to create panoramas -- the best way to get a sense of garden spaces! =) Weed cloth or not: I wouldn't have used it, but I wouldn't have added the gravel either. Reasons: both require more work; gravel takes up space that could be used for soil; and there's been some research done that says that the soil just above a boundary layer (like gravel) actually retains more water because of the change in density between the layers or something like that. I'll have to look for that again. I like the tanks though!

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  2. I forgot to ask: how long will those tanks last?

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  3. Alan, excellent point about the gravel. I found a good article about this: http://www.puyallup.wsu.edu/~Linda%20Chalker-Scott/Horticultural%20Myths_files/Myths/Container%20drainage.pdf.

    Now the question is whether we should empty out these massive tanks and do it over. I'm inclined to say no. Bamboos like moisture and since these tanks will be on a drip line, I doubt that they will become water-logged. As you can see, I'm trying to find arguments for NOT removing the gravel now that it's in place :-).

    I added some info about the longevity of these tanks in my post above. They should last for quite a long time, even though no manufacturer seems to give even rough estimates.

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  4. (I posted but not sure where it went, so hope I don't double-post)
    .
    Well you have 3" of gravel in a 24" tall tank. Assuming you left 1" unfilled at the top, that's 3"/23" or 13% of the potential soil volume taken by gravel.
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    Can you live with that? I know I could based on the amount of work involved to empty them. =)

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  5. Alan, I decided I can live it with it, too. There's still tons of soil in there, and the species I'm going to plant aren't giants. We'll be fine :-).

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  6. You can always use some crushed aluminum cans for a drainage layer instead of gravel. Cheaper, too! As for your 2" round tank...wasn't it 2'????

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  7. Becky: Duh, of course it's 2' instead of 2". That's what it's always good to spell out measurements :-).

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  8. How did the bamboo project wind up? We are thinking of doing the exact same thing in our backyard in Northern Virginia (where bamboo is plentiful, but completely outlawed by our HOA) I figure if I contain it, they can't stop me. I'd love to know how it's going and see some updated photos.

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  9. VillaBacio, we did plant the stock tanks (see here) in early December. Not much has happened since yet but I'll post an update as soon as the bamboos begin to shoot.

    Has your HOA categorically banned all bamboo, or just in-ground planting? Metal stock tanks are a great way of containing bamboo. As long as you don't have any drainage holes in the bottom or where you can't see them, I consider them completely safe. And do keep an eye on the drainage holes in case rhizomes want to escape.

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