Escapees! Get em!
I had a yard full of escapees from my bonsai endeavors. Was I worried? Was it time to call in the bulldozers? Not yet-you
see, these escapes were controlled escapes. The following article is about my experimenting with controlled escapes using
Portulacaria afra species and varying methodologies.
One often hears the advice "Put it in the ground and let it grow!" Sometimes there’s no safe place to do this, so
another option is to leave the plant in the pot and let the roots escape out of the drain hole. This "escape method" is briefly
mentioned in several places, so I thought I’d give it a try.
The idea behind the controlled escape is that the plants will still have enough roots in the pot to lessen the shock and
decrease the recovery time needed after being root pruned. Throughout this article I will use the term "experiment" for lack
of a better word. There is no control, no charts, no formulas-just my own observations. I started this observation in the
summer of 2006, with plants added as cuttings were made.
Preparation, background information, and materials
I wanted to find out what the best way to allow escapes would be in terms of getting growth and interest with the least
amount of maintenance and work in Portulacaria afra. Plant it in plastic pots and set them on the ground? Plant them in clay
and bury the pots? The only way to find out was to try many different methods.
To do a controlled escape, a pot must have drain holes. The more, the better. What one does not want to happen is that
the roots completely block all available drain holes for a long period of time, leading to overwatering of the roots still
in the pot and causing them to die back. In my case, this was important as P. afra does not like to be standing in water (wet
feet) even though it likes more water than most succulents. While the plant is in escape mode, this dieback may not be caught
because the escaped roots would be providing the nutrients. When the escapes are cut off, there may not be enough roots in
the pot to support the plant and we are back to basically having a cutting. So, the more drain holes the better.
There are several things to consider when choosing a pot for a controlled escape-construction, drain holes, sturdiness,
and costs. The types of pots I used were either clay or plastic-no mica, metal, or wooden pots (for reasons mentioned below).
Most of the clay pots used were the terracotta, "off the shelf" variety available at any box store. The biggest was the
6 inch diameter type, as most of my plants are shohin sized. Regular pots (same depth as height), azalea type pots (wider
than tall), and fern pans (height is about half the diameter).The pots other than terracotta were bonsai pots of varying types
of clay and sizes, none over 10" wide and mostly shallow. The regular pots and the fern pans each had one drain hole, with
the azalea type having slit like drainage holes that went vertically around the bottom of the pot about an inch high.
The other type of pot use was plastic pots. These fell into five categories: bulb pans, black generic nursery cans, terracotta
colored pots from a box store, seedling flat and recycled water bottles.
The bulb pans were circular 8" and 10" pots left from repotting purchased plants. These have many small drain holes in
the bottom flat area and are only a few inches high.
The black nursery cans were varying diameters and mostly around 8 inches in height. Their drain holes are along the edge
of the bottom, with each hole halfway up the side and half way on the bottom. This is so a pot placed flat on a hard surface
can still drain easily out of the sides.
The plastic pots from a box store were all terracotta colored, from 4" to 6" in diameter, and proportioned the same as
clay normal pots (diameter and height similar). All the multiple drain holes are along the bottom.
The recycled water bottles were the 20 oz clear screw type. To prepare them, the top funnel shaped area was cut off leaving
just a cylinder closed at one end. Multiple narrow slits were cut along the bottom with scissors, with half the slit on the
side and the other half on the bottom. Basically I just took the first inch of a pair of scissors and made two snips into
the bottom edge at slight angles to each other and removed the little chunk of plastic.
The seedling flat was a flat cheap plastic tray with multiple drain holes and slits along the bottom.
Mica pots were not used, simply because I have none. Metal pots rust and would be dangerous to handle after rusting in
contact with the ground. Wooden planters would draw bugs and rot fast in our high heat and humidity.
Most of this experiment was done in a fenced in portion of the yard. The area was prepared by turning over shovelfuls of
yard soil and removing any existing crabgrass and other weeds. The location is on the south side of the house, is in dappled
shade from a pine tree until about 1 pm, and then is in full sun from then until sunset. The plants not in this area (referred
to as the "garden" from now on) were either on the west side of the house against the side, or on the east facing back porch
(these were pot –in-a-pot escapes only).
Soil and depth
The plants in the garden area were mainly potted in yard soil from the garden area. In my yard, yard soil consists of mostly
sand with some organic material. Most of the organic material was pine needles and pine bark from surrounding trees, with
some dead grass thrown in for variety. Our yard soil has good drainage, and was convenient and cheap.
A few plants were planted in bagged Schultz cactus mix while it lasted. The plants in other areas were planted in either
Turface or a mix of turface and yard sand. Plants placed on the ground were filled to the rim with soil, while plants placed
in holes were filled to within an inch or so of the top.
The actual placement of the pot in relation to the ground/medium was one of four methods: directly on the ground, partially
buried in the soil, completely buried in the soil, or on top of soil in a larger pot.
The pots themselves in the garden area were placed close together to fit as many as possible into the limited space.
The plants were fed on an admittedly haphazard schedule using several different types of fertilizer and application methods.
The plants for the experiment were fertilized at the same time and the same method as the plants being cared for in pots,
with the exception that all of the plants in the garden area were fertilized more with goat manure than the potted ones simply
because it was easy to throw buckets of manure over the fence into the garden area than it was to apply it in every pot. Some
of the manure made it into the pots, some went between the pots. After the dry manure was thrown over the plants, they were
watered with a hose to wash the manure off the leaves.
Watering and other care
The plants were watered on a varying basis. When I was also growing tomatoes in the garden, they were checked daily and
the Portulacaria ended up getting watered about once every other day. When the tomatoes ceased to be, the watering happened
when the plants looked wilted. In the summer they were watered more frequently than in the little bit of winter. The few times
there was a warning about possible temperatures under 35, a wind block of fabric was clothes pinned around the garden and
the plants watered well that night. The other plants were also covered with sheets and watered well.
Trimming and styling
No special trimming or styling was done. Several times a year the overly tall shoots were trimmed back as unchecked they
tended to shade out the lower plants and I wanted to keep the lower branches growing on the Portulacaria. Trimming method
was either judicious random use of scissors or I took the weed eater and whacked down the ones that were substantially taller
than the others. No other consideration to styling was done.
Portulacaria afra was the sample species, chose for its quick growth, easy propagation, and because I had an abundance
of them. The plants ranged from straight cuttings (telephone pole looks, nothing but a stick with shoots regularly spaced)
to plants that had potential but needed to grow or were boring and I was hoping they would develop interesting roots that
could become a focal point. Mainly the normal variant was used, with a couple of variegated plants added as they were obtained
(Variegated results discussed separately).
Now for the important part…..the actual results!
When I first started with Portulacaria afra, my bonsai teacher told me that his plants always seemed happiest when slightly
root bound. Keeping this in mind, I potted plants that had roots in small pots, cuttings in even smaller pots. Overall, plants
that had filled the pots at least half full of roots before escaping grew more vigorously than plants that had few roots before
the roots escaped. By grew vigorously, I mean had the thickest diameter of growth, the most branches, and the most leaves.
This was partially because plants that had many roots in the pot had fewer tap roots than ones that grew straight out.
Advantages and disadvantages discovered of each method
Pots directly on the ground (not buried)
Most of the post on the ground were the terracotta kind. I ran into a big obstacle with them in that they tended to fall
over because the ground was uneven and the sand would wash from around them when I watered.
Since I do not pay daily attention to the garden area, a tipped pot might go a week before being noticed. Sometimes they
would fall over between other pots and go unnoticed for even longer. The tipped over plants couldn’t escape (the roots
wouldn’t come out of the drain holes if there was light), the soil would fall/wash out, the fertilizer and water couldn’t
get into the pot. I finally ended up corralling all the pots into a circle and placing bricks against the outside ones to
hold them all upright. Because of this, they didn’t have as much time to escape as the plants buried partly or completely
in the ground and for my purposes didn’t advance the experiment as much as I would have liked.
Another disadvantage is that it took more water to water them. This was because I filled the soil level to the rims to
try and stop them from tipping over as fast. The water tended to run off the sand and not soak in, so I’d have to make
two passes. The high soil level also meant round fertilizer pellets rolled out of the pots and went between them. Water based
fertilizer had a similar problem as regular water and did not get much chance to soak in.
Placing them on the ground did have one clean advantage at repot time: I didn’t have to dig them up out of the ground!
A few pushes to tip the pot over and sever the roots coming out. Setting up their area was easiest; no holes to dig-just set
the pots down.
Weeds did not cultivate the area between the pots set on the ground as fast as they grew around the pots that were buried,
possibly because the available ground area was shaded. Most of the weeds that grow in that area like lots of sunlight.
Pots set directly on the ground were also the easiest ones to check and see if the plants had escaped: simply lift or tip
the pot and see if it moves! However, my curiosity caused me to move pots that had just started escaping and this slowed down
some escaped root growth.
A similar idea was used by placing small plants on top of the soil of larger plants. This method was not always done on
purpose… occasionally I would set a smaller plant on the soil of a larger one "just until tomorrow" and would forget.
The was no noticeable difference, either better or worse, between plants escaping into larger pots and plants escaping into
the ground, possible because in both cases the root growth met no obstacles.
Partly and completely buried
The partly buried pots were buried halfway up the pot in the soil, while the completely buried pots were (obviously) buried
until the rims were at ground level. Watering took less water with these, as the soil levels were not up to the rim since
I didn’t have to worry about them tipping over. This meant that any water received would be held long enough to soak
into the soil instead of running off. The completely buried plants had an additional advantage in that the plants ended up
forming depressions when the soil settled. When I watered (or it rained), additional water would settle into these depressions,
giving the plant more water and time to absorb the water.
Fertilizer was also more readily held near the tree instead of supporting the colony of weeds, whether it was pelleted,
granular, or water soluble. With the amount of fertilizer and the lack of pot tipping, the plants grew stronger than the plants
on the ground.
There were several disadvantages, especially given that I was looking for the easiest way to get results. The completely
buried plants were a lot of work to dig up! First, the sand around the plant had to be felt around in until the rim was identified.
Through many watering sand built up around and over several pots so the rims weren’t obvious at first glance. Then,
I could try to just pull the plant up. Usually though, the pot and any surrounding neighbors had to be completely excavated
and then the escaped roots could be severed. Sand packs around a pot pretty hard when repeatedly watered and settled. This
meant that I couldn’t just pick a plant in the middle to take up; several other plants had to come up in the process.
Had I not placed them so close together and made notes of the pot sizes this would have been easier.
Another disadvantage was it was easy to forget how long ago a plant was buried. I tried marking them with different types
of stakes, but high winds/squirrels/hose water knocked most of them around. Several plants were dug up twice while other ones
were not touched.
A big problem I ran into was that the plastic pots (bulb pans, black nursery, or box store type) were too flimsy to handle
being wrenched out of the ground at repot time. This lead to many split pots, several split fingers, and a few bad words.
Surprisingly, the recycled clear water bottles held up better than the "garden" type of plastic pots! At first I attributed
this to the round shape until I had the same problem digging up the round pots.
Low trailing branches had a tendency to join their neighboring plant, and if they were left alone started growing roots
where the nodes were in contact with the soil. Weeds also grew in and around the partially and completed buried plants, sometimes
completely obscuring the plants and leading towards leggy growth.
The plants placed directly on the ground in the garden area did not have many escaped roots due to the tipping issue. The
few plants placed on the ground on the west facing wall of the house were able to escape, although the escaped roots were
mainly thick tap roots. While this kept the tops vigorous, most of the tap root had to be cut off come planting time.
Both the partially buried and the completely buried groups had similar amounts of rootage that escaped from the drain holes.
However, the completely buried pots yielded plants with slightly more growth of the above ground parts. I believe this is
for two reasons: shading of the roots and more trapped water.
I found that for this method, the best drain holes are on the sides of the pot instead of only on the bottom. This slowed
down the formation of overly large tap roots, although the roots circled the pot and still escaped.
In every plastic pot, the escaping roots split the pot (which was part of the problem when digging them up). Most of the
splitting was between the bottom drain holes, though one plant (on the west side of the house) split the side of a pot after
forcing itself out of a small hole in the side. The size of the drain hole itself did not seem to constrict root growth, as
the root simply enlarged and bent the plastic out of its way. The escaped roots out of the clay drain holes tended to stay
the same size as the drain hole they escaped from.
The cuttings that were grown in the seedling flat ended up with a tangled mess of roots after pushing out through the numerous
holes in the bottom. I ended up having to use a shovel to sever the whole mess and spent quite a while removing pieces of
plastic from between plants. Seedling flats are not good to use for this!
The most top growth was from the plants in completely buried pots, with no noticeable different between clay or plastic.
Since the pot was buried, I played a guessing game with myself before I dug it up – clay or plastic? I was not able
to tell at a glance what the material of the buried pot was based on the top growth.
I did have some issues with leggy growth, but this was due to plants being crowded and trying to reach for the sun. When
a plant with leggy growth was taken up and repotted and given more space, the leggy growth fattened up normally and back budded
well. If length (not diameter) was a goal, extreme crowding of foliage would be one method.
I could tell which plants had formed thick tap roots by the appearance of the top growth. A plant that suddenly had one
or two branches take off during the growing season would have a few thick tap roots. A plant that grew multiple branches and
branchlets would have a nice root system. There was a direct correlation between the size/number of roots and the amount of
branching. So a plant that noticeable had few strong branches at the expense of others needed to be dug, the tap root trimmed,
and repotted to encourage more even growth.
On Heated root balls and Slower Growth.
Most of the plants above the ground were in clay pots. As the area is in pretty direct sun, I thought the plastic pots
would heat up more than the clay ones and hence chose to bury the plastic ones. In my experience, a plant in a pot that is
exposed to sun grows slower than a plant whose pot is shaded from the sun. Since the temperature here commonly is in the 90’s
in the summer, a pot in the sun would have even hotter internal temperatures. When the temperatures get high, growth stops
- so using a material above ground that is slower to heat up would be beneficial by giving more growing time. I’ve noticed
that pots with shaded root balls (from being crowded) have plants that grow stronger than the pots in direct sun. For instance,
pots grouped in a circle would have the inner plants noticeable taller and bushier compared to the outer ring. This held true
during this experiment-the cooler pots (buried in the ground) grew better than the ones above the ground not shaded.
Variegated vs. Normal
I ended up not being able to compare the results with the variegated plants to the normal plants because the growth rate
between the two, even given the same growth conditions, was too different. The variegated variety grows much slower and doesn’t
thicken like the normal variety. The tendency is towards lanky trailing branches, even in upright plants. If the variegated
plant was shaded more than a few hours it did poorly-they seem to need more sun than the normals. I’m not sure the variegated
will ever make good bonsai… for now they are just a pretty contrast to all that green!
So why not just plant them directly into the ground? Well, I did also plant several plants directly in the ground. These
actually did worse than any other plant! When I dug them back up, I found the plant spent most of its energy in putting out
a few tap roots. The normal type plant in the ground with no root confinement put out less growth than even any of the variegated
type! Plus, they had less fine roots (as expected) near the base, it took longer to dig without damaging any other plants
roots, and it would be impossible to move them in an emergency (hurricanes come to mind). With my schedule (read: tendency
to forget), I was also concerned that a plant would get beyond the easy to repot stage before I got around to digging it back
Another problem with plants directly into the ground is the wildlife! Moles seem to favor that area for their tunnels,
leading to the demise of most of the vegetables I had tried. Armadillos had no problems digging into the ground plants either.
The pots stopped the moles and the armadillos from damaging the plants.
After experimenting with the escape method on Portulacaria, I have come to the conclusion that for optimal bonsai interest
the plant should be
a) In a clay pot, preferably with several holes-easy to dig up
b) Buried up to the rim in the ground
c) Given a bit of breathing room
d) Dug up if signs of over eager tap rootage show (few branches that take off instead of the whole plant)
Labeling the plant with the date of being buried is a time saver-no sense in digging up a plant you just planted a week
I plan on continuing to allow plants to escape their pots…. I may need to borrow a bulldozer if I forget a few…anyone?
For more technical information about Portulacaria afra, an excellent monograph can be found here: http://www.phoenixbonsai.com/Portulacaria.html.
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