Rick Shory

Offering a little something you might not otherwise have

potted sundew floating in water

Grow a sundew plant

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Create a microhabitat for a bog plant in a floating pot.


Round-leaved sundew (Drosera rotundifolia) is an intriguing little plant. Part of the intrigue is that sundew is insectivorous, though most of what it “eats” are tiny gnats and midges, nothing even as spectacular as a housefly. The plant maintains its mystique by being seldom seen. It’s not rare. It can be profligately abundant, in the right habitat. But that habitat can be difficult to access — quaking bogs.

A quaking bog is a lake, or lake edge, where sphagnum moss has grown in the water to sufficient quantity that is has formed a floating mat. You can walk out on it, if you don’t mind getting your feet wet. It will support you, but it “quakes” (moves), as you step around. You can play by shifting your weight to alternate legs, and get the surface mat rolling in lazy waves.

The classic explanation of why insectivorous plants grow here is that it’s acidic and nutrient-poor. The plants get nitrogen from insects they can’t get from the ground. But part of it is also physics. Sundew is a tiny plant. If it tried growing on the shore, it would dry out when when water levels dropped, and drown when they rose. Instead, it rides up and down on top of the floating moss, and stays constantly moist despite any lake level changes.

But sundew can also be found in a few curious microhabitats. I lived for a while in Bellingham, Washington, and heard that sundew grew at a certain lake, a popular day hike. I went there, and scoured the area for this little plant several times, never finding it.

The lake was in a rock hollow, scooped out by glaciers. The shore was clean-edged, no quaking bog. Conifer trees grew all around, but evidently the bedrock did not give much to dig their roots into, because they would blow down in storms. The lake was crisscrossed by fallen logs.

Finally, somehow, I thought to look out on the floating logs, and there were the sundews. Not many, but there they would be, right at the edge where wood met water. Wet wood is certainly a low-nitrogen substrate.

The plants were not on logs that draped into the lake. Those would be alternately wet and dry through the year. But logs that were entirely floating could ride up and down with lake level fluctuations, and allow the tiny sundews to stay constantly moist.

So that’s the clue to growing a sundew, without having to water it by eyedropper. You might want to scroll to the bottom to see where this is going.

I had a few sundew plants someone had collected as botanical specimens from a bog. I thought I’d see if I could keep them alive.

sundew plant

Sundew specimen

I used my largest spade bit.

one and one quarter inch spade bit

Spade bit

I drilled into a scrap of half-inch-thick cedar board.

drilling into board

Drill

I cut out the drilled section to form a cup.

shallow square wooden cup

Cedar cup

Notice that I drilled the point all the way through, to make a hole.

showing hole goes through to the back

Hole in back

I test-floated this in a little “elevated pond” I have. This is the only way I have found of growing some water plants, without the raccoons tearing them up every night. The “pond” is suspended as a hanging planter, up off the ground. I have it set up to refill every morning from the drip irrigation. The local birds drink from it, and use it as a birdbath.

showing the cup floats with a little water standing inside

Test float

I wanted to make sure water came through the hole, and kept the interior constantly moist. With this satisfactory, I potted the sundews along with a bit of the sphagnum that had come from the bog.

sundews potted into cedar cup

Potted up

Then, I floated this back in the pond.

potted sundew floating in water

Floating

This idea might be useful for growing other insectivorous bog plants.

 

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