Rick Shory

Offering a little something you might not otherwise have

potted sundew floating in water


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Grow a sundew plant

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.

 

graphic, tree re-work plan


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Shorten cherry trees

A grafting experiment that did not work; to make tall fruit trees short.


In winter of 2019, Arne (I’ll call him), of a local Ecovillage I’ll refer to as “Bamu”, contacted me about some cherry trees. This post is a record of the process. It’s all too easy to never report on failed experiments. But experiments never fail. You always learn something, if only what doesn’t work.

The three cherry trees in question were very tall. They were evidently seedlings, not any improved variety. They bore small, mediocre fruit. They were casting dense shade on other parts of the orchard, preventing fruiting there. The community had decided it was time to try and do something about this.

Everybody else Bamu had consulted said, “Just cut ’em down!” I suppose my name came up because I have broader perspective on what you can do with fruit trees.

In the fruit growing country east of the Cascades, orchardists routinely re-work big fruit trees, but in urban Portland this is scarcely heard of. Nobody knows anything but “Cut it down!”

In commercial orchards, this would be a huge economic waste. There is no need to completely remove trees, then plant new trees, then wait years, or decades, till they get to bearing size. Instead, trees are re-worked.

If one variety of, say, apple goes out of fashion, an orchard will “change” all the trees in a block to a more popular kind. Workers go through, cutting off the limbs and grafting the new variety onto the stubs.

This amounts to a rather severe pruning. When the trees grow back out, the new limbs are from the grafts, and therefore bear the new type of fruit. The trees can be in full production again in only a few years.

graphic, re-working a tree

Re-work

This diagram is simplified. In practice, the grafting is done at a particular time of year, not when the host tree has fruit. The illustration is to show the change of fruit variety.

The cutting back can be to any degree. One extreme is to put a great many grafts out on all the small branches. This is of course very labor intensive. The other extreme is cutting the tree off to a stump, and grafting on to that stump. This requires the minimal number of grafts. Orchards generally do the larger limbs, or stump, to control costs.

Orchards are already controlling the size of their trees, so the primary reason for re-work is to change the fruit variety. In urban areas, on the other hand, tree size is a major issue. Often, fruit trees have been let to grow for years, with little thought. When they start to bear, all the fruit is way out of reach.

Part of my proposed re-work of the Bamu trees was to control their size. Cherry trees naturally grow very tall, one of the largest types of fruit trees. The use of “dwarfing” rootstocks is now widespread. Trees grafted onto such roots grow to only a fraction of the standard size.

A variant of that is “interstem”. The tree starts on a sturdy rootstock, not necessarily dwarfing. Then, the dwarfing moiety is grafted on, then the desired variety is grafted onto that. The section of dwarfing stem between the roots and the top causes the whole tree to be dwarfed.

graphic, interstem

Standard, dwarf, and interstem

In the case of the Bamu trees, the roots were what they were. I thought of trying an interstem so that when the trees re-grew, they would fruit at smaller size. Otherwise, varietal cherry grafted onto this seedling rootstock would grow to just as large a size as before.

The appropriate technique for grafting onto a large cut stem is the bark graft. This video shows exactly how to do it.

I made this video on request from my niece’s husband, Ryan. In the Southeast, where they live, there is a widely planted ornamental, the Callery pear (Pyrus calleryana). Birds spread the small inedible berrylike fruits, and Callery pears come up everywhere.

Ryan had a big such tree at the new house they bought, and asked me if it could be grafted to edible pears. I couldn’t visit at the time of year to do it myself, so I made the video. Ryan followed the video, and now has ‘Avers’ pear growing on the Callery pear stump.

bark graft

Desirable ‘Ayers’ pear bark-grafted onto Callery pear stump

Pear trees, like cherry trees, want to grow big. Even though Ryan’s pear tree is no longer a trunk towering up to the sky, it is still a challenge to control the size. Thus, the idea of the dwarfing interstem on the Bamu cherry trees.

I mapped out a plan where the trees would be cut off to stumps. Then scions of a dwarfing cherry would be bark-grafted on. This would be in the second week of April, the correct time for bark grafting.

These bark-grafted dwarf cherry scions would grow out and serve as the interstem.

graphic, tree re-work plan

Plan to re-work trees

When the interstem had grown sufficiently, varietal cherry would be grafted on. These grafts would be bud grafts, done the second week of July.

So the varietal cherry would be in place within one growing season. Then it would be a matter of re-shaping the trees for productivity.

However, there were other considerations. The community at Bamu had been using the large cherry trunks as hammock supports, and the area had a fire circle which was a social focal point. They wanted to keep the hammocks. Even if the tree tops were taken off, they would like to have the trunks remain, to build some sort of pavilion.

graphic, other uses

Other uses

The discussion went back and forth. There was the idea of cutting off the trunks higher, perhaps to six feet, or ten feet, and grafting on top there. I pointed out that growth from grafts grows upward, and so all the fruit would again be out of reach.

Then came the idea of notching in the bases of the trunks, to “separate” the upper section, and get the bases to behave as if they were cut stumps. I explained this could effectively act as girdling the trees, and they might die.

graphic of notches and grafts

Compromise, graft onto notched trunks

Still, with all considerations, we settled on this compromise and decided to try it. At worst, the trees would die, which was no worse than the original “Cut ’em down!” proposal. And we would learn something.


On March 20, an arborist topped the cherry trees, and notched them at the base.

notched bases of cherry trees

Notches at base

tall trunks notched at base

Topped trunks of notched trees

On April 11, I bark grafted the trees. I used scions of a rather strongly dwarfing cherry rootstock. Trees on this rootstock can be kept to 15 feet in height.

bark graft

Individual bark graft

On the south tree I put 28 grafts, the middle tree 22, and the north tree 27. This amounted to grafts every few inches around the circumference.

People at the community were interested and curious. “Why so many?” they asked, “Do you need that many grafts?”

line of bark grafts

Bark grafts

I explained that I always like to make lots of grafts, to try and get some kind of statistics. Seldom do all of them grow; and if there are lots, you can get an idea why.

For example, if drying out from strong sun causes them to fail, I would expect to see it more on the south side of the trunks and not on the north. If by some chance they do all grow, you can choose the best.


Arne was proceeding with taking the bark off the upper trunks, but it was slow going. As an idea, it hadn’t seemed too hard, but when it came time to actually do it, working so far off the ground was awkward and strenuous.

Also, the bark was not peeling as readily as I was used to. Bark peels easily, or “slips” when the cambium cells are actively growing. The trees seemed compromised, in that the cambium had not become as vigorous as on a healthy tree that time of year.

On April 28, some of the grafts looked promising. People in the community were hopeful the grafts would take. “We’re rooting for them!” Unfortunately, trees have to root for themselves.

bark graft showing some leaves

Bud growth

I was already doubtful the grafts would succeed. I look for vigorous generation of new leaves, not just unfolding of existing ones, as seen here. I thought it was a false start, the scions surviving on stored moisture, and what water could diffuse in from the stock below.

The hammocks were back up, and I could see how much the community loved them. I was a little concerned the grafts might get knocked by activity around them; but, well, there were lots of grafts. It’s always statistics. It would have been a mistake to cut the trees off to the ground. This experiment was worth a try.

By May 24, it was clear the grafts had failed. Arne had not been able to keep up with de-barking the upper trunks. I doubt this would have made much difference.

bark grafts not alive

Failed bark grafts

I noticed the de-barked trunks were wet with sap, to the extent some mold was growing on them. This indicated the roots were still “seeing” the upper trunks as alive, and so the roots were expending their strength to support them.

A check on July 17 showed some growth from above the de-barked area. This was the worst of signs. I meant the work was essentially behaving as a girdle. The tree was continuing to try to keep the top alive, at the expense of further exhausting the roots.

trunk showing shoot growth

Shoot growth above de-barked area

I believe this was the major factor. Minor factors could have been:

  • The initial cutting on the trees was three weeks before time to do the bark grafts. Usually, scions are inserted immediately as the limbs are cut, before the ends can dry back or the plant cells otherwise reorganize.
  • It could have been the time of year. Whereas apples are very reliable to graft in spring, cherries are less so. If this were the major factor, though, at least a few of the grafts should have grown.
  • Normally, after bark grafting, the entire cut end of the limb is sealed over to prevent water loss, and make maximum moisture available to the grafted scions. Here, since the trunk was only notched there was no way to seal over the end.
tall stump

Tall trunks did not live

The cherry trees have died. The Bamu community is going ahead with planning to construct a pavilion, using the dead trunks as support. The formerly shaded sections of the orchards are expected to be more productive.

compact plant


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Bonsai your wax vine

You can “bonsai” a wax vine, for a compact house plant.


Wax vine (Hoya carnosa) makes a good house plant, tolerant of low light and neglectful watering. However, its natural growth form is an extensive vine. If you’ve got room for that, it’s fine.

Here we have one in the bathroom. Notice that it’s also tolerant of being potbound. All that vine, growing out of a small flowerpot.

long wax vine

On bathroom shelf

Of course it would have long since toppled off the shelf, except it’s guyed up by strings. The anchors are those stick-anywhere hooks.

view showing flowers

Side view

The flowers are nice. We would be glad to have more of these plants, but no room for another big vine.

Wax vine is easy to propagate by cuttings. We started a cutting in another small pot.

A wax vine plant grows in spurts. It sits there a long time, gathering strength. Then one day, a vine shoots out. If you let it, it’ll grow six feet or more.

Instead, every time a shoot grew out one node, we pinched off the tip.

shoot with tip pinched off

Shoot pinched after one node of growth

Most plants, If their leaves are not allowed to develop early on, those leaves die. However, wax vine has the ability to keep new leaves small, and then later enlarge them to full size, weeks, months or even years later.

In the picture below, these new leaves are the two small fingerlike structures above and below the pinched-off stem tip.

pinched tip

Pinched tip budding

The part hanging down is the beginning of a flower cluster.

By stopping growth at the pinch, the plant’s strength “builds up” there. Usually, after a time, growth resumes by enlarging the leaves and making flowers. Below is a picture of the flower buds, further along.

partially grown flower buds

Flower buds developing

Finally, they bloom. Don’t pinch off wax vine flower clusters as they fade. The down-curving stalk of the cluster will stay alive. Later, it will make a new flush of buds on the same spur, and bloom again.

wax vine flowers

Flowers

By pinching this way, the whole plant stays most compact.

compact plant

Compact plant