" Portulacaria afra, the Elephant's Food or Spekboom:

an ongoing monograph which contains some of the areas of

both knowledge and ignorance pertaining to this plant "

© 1999-2024 by Robert J. Baran



TABLE OF CONTENTS

PART I
TAXONOMY
ORIGIN
HISTORICAL REFERENCES

PART II
APPEARANCE
THE TRUNK
THE BRANCHES
THE LEAVES
THE FLOWERS AND FRUIT
THE ROOTS
VARIETIES

PART III
TEMPERAMENT
PROPAGATION
HORTICULTURAL & OTHER USES
CONTAINERIZED

PART IV
BIBLIOGRAPHY

PART V
  THE OTHER PORTULACARIA
THE FALSE PORTULACARIA
BIBLIOGRAPHY



PART III



TEMPERAMENT

Outdoors, Sunset Zones 13, 16, 17, 22-24.  Outdoors with overhead protection, Sunset Zones 8, 9, (+10, per RJB personal experience), 12-15, 18-21.  As a houseplant, anywhere with adequate bright light.  Will not stand much frost, and should be grown as a succulent, although P. afra seems to thrive in a wider range of soil conditions.  In the wilds of South Africa, large plants do survive the cutting frosts of bitter winters by growing dense enough to provide their own natural cover.  Drought tolerant and fire resistant, it will endure desert sun and heat which the Crassula jade plant will not.  Water well, and then let the soil dry out completely.  Chronic overwatering can kill the plant by easily encouraging the growth of fungus.  Soft or soggy branches are a sign of too much water.  This plant does not do well in continually humid locations.  Leaves turning black and falling, stem ends turning black and going soft, roots rotting, these are signs of the plant being too cold and probably too wet.  Pare off the blackened parts of the stem and dust with hormone rooting powder containing fungicide.  Keep in a location with temperatures above 40 °F (4 °C).

In the wilds a mistletoe, Viscum crassulae, is known to be a parasite of P. afra.

Resistant to diseases, sometimes the leaves can get aphid or white fly parasites in relatively small quantities with no harm to the plant.  Spider webs at the branch tips can be unsightly but effective in controlling the aforementioned insects.  Ants might also control the insects. 

The nematode Meloidogyne incognita is listed as a pathogen to many plants in Hawaii, including P. afra.

Telostylinus lineolatus, long-legged flies of the family Neriidae, have been observed in the stems of the elephant bush (P. afra) in Hawaii.  Relatively little is known about their biology, but it is likely that the larvae of most species are saprophagous and feed on decaying vegetable matter.

Selenaspidus portulacariae, a species of plant lice in the family of armored scale insects, was found on imported specimens of P. afra in the early 1950s.

Mealy bugs and root mealy bugs have also been mentioned as likely problems.  For the former, remove the insects with a small paintbrush dipped in methylated spirits, and spray with a contact or systemic insecticide.  Repeat every 2 weeks until clear.  For the latter, likely if bottom leaves fall and there is little new growth, wash all soil off the roots, swirl in a contact insecticide, and allow to dry before repotting in fresh compost and a washed pot.  Leave dry for two weeks, giving not more than an hour or so of direct sun during this time.

Minor injuries to leaves heal with brownish-white scars.  Ants or leaf-cutting bees, for instance, might be responsible for partial damage on a small number of larger leaves on landscape plants.  The damaged edges seal and the leaf -- and plant -- goes on with its normal life. 

Vine weevils may be responsible when round pieces are missing from leaf edges and the stem is swollen and there is little new growth.  In this case, either use a systemic insecticide to kill the larvae in the stem, or prune the stem from the base and remove slices of the stem until the larvae are found.  Dispose of the larvae and re-root the remaining stem.

P. afra will not tolerate some chemical sprays, particularly petroleum-based chemicals.  Defoliation, followed by quick recovery, has been noted after exposure to Isotox and Malathion.  However, Volck Oil Spray appears to have no affect.  Soapy water or just the pressure from a garden hose seems to be sufficient in ridding the plant of most insect pests.

Overspray from Avid (an insecticide) results in new leaves being pointed at the tips, smaller, oval and more narrow in shape.  These look mutated for about 6 months, then normal shoots grow and afterwards the plant looks normal.

Garlic-based sprays are said to work well.  Such a spray every two-weeks is recommended for cyclic preventative maintenance.

There have been limited observations of birds picking at leaf pads and branch tips, causing minor damage thereto.  House cats and dogs are generally indifferent to P. afra, although the latter have infrequently been known to chew on/tear up smaller specimens as part of a reaction to any non-grass vegetation within their territories.  This may be due to canine boredom. 

Small (.5 to 2 mm) roundish slightly raised or flat "pimples" of brown or green sometimes are seen on a very small quantity of the leaves.  (A single one-gallon container nursery specimen has been seen, however, which had approximately one sixth of its leaves bearing these marks without other noticeable difference.)  Usually only one mark is observed on a given leaf, though up to four (of "mixed heritage") have been recorded.  They seem to occur slightly more frequently on the upper surface of the leaf than on its lower surface, although they have been observed on both sides of the same leaf.  (In that case, the marks were on different places on their respective surfaces -- no apparent correspondence existed between the top and bottom "pimples.")  It is extremely rare to discover adjacent leaves that both have such marks.  New leaves have never been observed to have "pimples" of any types.  While the pattern of surface pores has been observed to remain intact across the leaf and the blemishes, the "pimples" have been found to exist just on the thin top skin layer, not visibly extending into the leaf pulp.  Their etiology is unknown, and there probably is more than one cause for these features.  They seem to pose no long-term threat to the leaves having them, and they may last for the entire "adult" life of the affected leaf.

Correspondant Susan Marsh (4 Feb 2011) tells us that, per an unidentified source at a bonsai club meeting, the brown spots are "just from [the plant] suddenly getting too much water after not being watered for a long time, [which is what] a lot of succulents do...  I went home and re examined those plants [so affected by spots] and yes, those plants had been subjected to a dry period of about six months (out in the garden I neglected) and then were brought up to where I watered every 1-3 days.....and the spots were indeed on the growth present at that time.  The new growth that started under the new watering plan has no spots..."

It is not clear what the symptoms are of specific nutritional deficiencies in P. afra.

It is said that sometimes when a P. afra has heavy exposure to grow lights but not actual sunlight, new growth might be edged in red.  Overuse of iron supplementation also could cause this coloration.

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PROPAGATION

Cuttings root very easily in most potting media without either rooting hormone or "greenhousing" with an enveloping plastic bag or glass jar, for example, if the cut end is kept dry.  The appearance of new growth will indicate when a little water is needed to be given.  The substrate should never be kept wet.  Cuttings can become rooted in water as long as the cutting is transplanted into a coarse soil mix as soon as roots are seen.

Early experience with a cutting that was not allowed to form a callous on the cut end demonstrated that before about one month was up the cutting (non-woody and at least 1 cm in diameter) needed to be put in soil or else it quickly rotted.  Admittedly, this particular cutting was kept on the edge of a window-less kitchen sink with varying amounts of fluorescent lighting, and thus had several strikes against it.  Correspondant Susan Marsh (4 Feb 2011) tells us that she "decided last September to take an ugly prebonsai and see what happened if I cut the roots off (making it into a cutting) and stuck it in a vase on the windowsill.  I did let the end dry for two days indoors on a theory that a callused end might not rot.  I stuck it into a clear cylinder full of those expanding polymer balls (black to reduce the light getting into the roots).  It proceeded to drop all of the leaves in about a week, and slowly grew them back.  It grew roots.  It stayed on the window sill for about two months until I had gotten tired of chasing the cat away from it, at which point I put it outside.  Since it's in glass I put it on the back of the bookcase I keep some plants on, so it's in shade.  It is wayyyyy happier than it was on the windowsill in terms of leaf color and vigor!  I even forgot about it when I brought plants in for both freezes we had so far this year and it didn't die...  I think the water insulated it from freezing.  So it's now 5 months old and still going.  I keep waiting for it to die, but so far so good!  The tricky part would be transferring it to soil, I imagine it'd have to be weaned off of being completely wet, perhaps in a hydroponic system..."

Other experience with a small but woody cutting -- 8 mm diameter and 10 cm long with branches -- after over a month in water produced at least two nearly 5 cm long thin whitish roots with no signs of rot and several tiny leaf buds opening.  The minimum survivable cutting size appears to be about 2.5 cm in length, at least 3 mm in diameter, and most importantly with at least 4 leaf pads. (Demonstrated for RJB by Icel and Tia Atchison in Kingman, AZ, outdoors July-November 2003.)  At least double that length seems optimal.  Semi-ripe cuttings taken in summer are most recommended, but fresh cuttings taken from outdoor plants as late as mid-December in Sunset Zone 13 and then raised indoors without special care are also successful.  It is said that cuttings over 2.5 cm in diameter need to have a dry callous form over the end which is to be rooted before this can occur.  Limited experience shows that Sunset Zone 13 cuttings of that diameter taken in June did not need to be dried to give good results. 

Removing a number of the smaller branches and cutting the remaining leaves in half appears to aid in preventing moisture loss on newly struck cuttings in very hot and dry climates only.  New growth can be expected to be seen within a week during warm weather, arising initially at the base of removed branches.  Allowing essentially all secondary growth and leaves to remain on a cutting could result in dehydration and withering of branch tips and older leaves, and delay the rise of new leaves.  It is not known how large and branched a non-defoliated cutting can be before it does not still successfully root.  Defoliation can be done up to several weeks after the cutting is struck: it appears that the sooner it is done, the quicker the cutting will root and leaf.  It is thus very easy to quickly get a well-shaped tree from a trimmed branch. 

Unburied discarded prunings of sufficient size have been known to root by themselves on either poor or good soil in a south-facing exposure in the springtime in Phoenix if an adequate (but as yet undetermined small) amount of moisture is gotten within a few days. 

The recommendation to allow cuttings to "harden off" a couple of days before inserting in fast draining, dry soil mix comes from Portulacaria expert James J. Smith, Vero Beach, Florida (Sunset Zone 26).  More humid location (on the eastern coast between Cape Canaveral and West Palm Beach) do have slightly different requirements than those needed to successfully strike cuttings in the arid desert area of Phoenix (Sunset Zone 13). 

In climates that are cooler and moister, defoliation of cuttings is NOT recommended.  The plant uses moisture from the leaves to form new roots, so when the leaves are paper-thin dry and new buds are showing at the base of the leaves then watering can resume.

Cuttings in soil can form good rootage of varied width and whose upper portion is sufficiently gnarly within three or four years. 

Elsewhere it is recommended to strike the cuttings in spring and summer, dust with hormone rooting powder, leave to dry for a few days, then root in dry compost.  Water after about 3 weeks when roots start to appear.  [The use of rooting hormone with this plant seems of more benefit to the gardener's peace of mind than to an actually improved success with cuttings. -- RJB]

If green branched cuttings are rooted, the lignification browning will be much delayed.  There is some evidence that cool weather can cause this browning to happen or at least speed up its occurrence. 

Suckers occasionally arise at or below the soil level from nodes.  Leaves and stalks which start below the soil level are pale green before emerging. 

Also, it is possible to propagate from seeds, if obtainable, but these are rarely available.  The tiny seedlings should not be allowed to dry out for the first 6 months.  It is recommended to grow the seeds in a half pot or tray which stands in an outer container of water until the seed tray surface is damp.  Use of seeds is of questionable necessity given the readiness of cuttings to root. 

Larger mature pads can apparently propagate in the manner of some true succulents, i.e. by being placed on top of dry sand or having their bases covered with potting medium.  Although preliminary tests in Phoenix, Arizona indicated to the contrary, photographic evidence from Port St. Lucie, Florida (east coast) shows the positive.  "The rootage seems to occur as long as the leaves aren't in full sun -- so it happens under parent plants, if the leaf falls on the shady side of the pot on the ground, or in this case, when the plant pot it fell into wasn't in full sun.  It is rather humid here, and I suspect that would help the end not to dessicate before it can throw roots."  It takes up to 3 weeks to root this well.  (Brought to RJB's attention in personal e-mails from Susan L. Marsh on 31 Oct, 16 Dec and 19 Dec, 2006.)



Photos © 2006 Susan L. Marsh.

It is not known how long untreated cuttings can remain viable.  It is not known how long rooted cuttings or specimens can remain viable without water or soil.  It is not known how well cuttings root in only water, although early results indicate that woody cuttings root better than green cuttings this way.  It is not known how much, if any, the lunar phases or companion planting might affect propagation success or overall growth rates.

P. afra is used as rooting stock for grafts involving P. afra, P. pygmaea, or P. namaquensis, per Rauh (pg. 133) and "Portulacaria".  That said, this method of propagation would seem to be dfficult and complex compared with rooting, although necessary or effective in special cases.  Apparently it is easier to graft other Portulacaria species to P. afra base stock rather than trouble oneself with P. afra to P. afra grafting.

Please see this article about additional propagation techniques.

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HORTICULTURAL & OTHER USES

Where hardy, can be used as a fast-growing informal screen, unclipped hedge or cut back as a high-growing ground cover.  By the late 1950s in the U.S., P. afra was little-known but grown in California for interest more than ornament, and also in cool greenhouses northward.

The roots of the trees bind the soil and are often planted around farmhouses as evergreen hedges in South Africa.  Live kraal fences for cattle are often cultivated from cutting of P. afra (iGwanishe) by the Xhosa there.

Available at nurseries in one to five gallon pots.  Rooted cuttings of "Variegata" have been offered in 2" and 4" and 6" liner pots.  (The species name has been seen on some factory-printed plastic identification strips as "afro.")  In early 2004 the indoor plant department of WalMart was seen offering a hanging plastic bowl containing approximately two dozen rooted and slightly cascading cuttings of this variety.  Cactus and succulent clubs also have offered rooted cuttings for sale.  It is said that the plant is so common in South Africa that some nurseries don't bother to stock it.

Some 50 km north and west of the aforementioned Addo is the Rockcliff Game Farm.  The Spekboom, a favorite of the greater kudu (Tragelaphas strepsiceros) and the critically endangered black rhinoceros (Diceros bicornis) -- occurs widely there.  The African buffalo or Cape buffalo (Syncerus caffer caffer) also is known to this in Addo.  This nutritious plant can support a higher biomass of large animals than any other ecosystem in South Africa.

      "Like Addo, Shamwari (30 km east of Addo) is excellent elephant and black-rhino country, due mainly to its dominant plant species Portulacaria afra.  To stock farmers it is known as the spekboom but in these parts it is also called 'elephant's food'.
      "So nutritious is this plant that it can support a higher biomass of large animals than any other ecosystem in South Africa.  This fact alone makes Shamwari potentially more viable than private game reserves in other regions."  (Getaway Magazine)

It is reported to serve as a source of ostrich feed on farms in the Cape Province and "highly favoured" by tortoises.

     "In some areas it is exploited by browsers such as goats, as most Spekboom is extremely palatable.  A sour form identical to the sweet form is, however, never or rarely browsed by domestic or wild ungulates.
     "[It forms] the backbone of the goat industry." (Bredenkamp et al)

     "Stuart-Hill (1992) demonstrated the role that elephants play in maintaining vegetation structure and promoting asexual recruitment of Portulacaria afra in Albany Thicket.  Elephants encourage coppicing in woody shrubs and promote the development of a skirt around P. afra plats.  Sigwela (1999) and Sigwela et al (2004) showed how significantly more seeds are dispersed by indigenous herbivores than by goats.  There have been several previous studies that examine the impact of goats and indigenous megaherbivores on biodiversity and ecological processes.  Most of the earlier work was done from an agricultural production prespective, where the vegetation was viewed primarily as a resource for browsing animals (Aucamp & Tainton, 1984).  There are two key vegetative traits that contribute to degradation of the Albany Thicket.  Firstly despite a high standing biomass, Albany Thicket has a low a nual production, thus giving a false impression of the amount available of forage available for animal production (Aucamp & Tainton, 1984).  Another is the very slow recovery periods of the main forage species such as P. afra, which can take up to 18 months to recover from 50% defoliation by goats (Aucamp & Tainton, 1984).  Also, the feeding behavior of goats, both as indivudals and as herds, differs from that of indigenous herbivores (Danckwerts 1984, Stuart-Hill 1992).  Goats are gregarious animals and tend to feed in groups around individual plants and vegetation patches, leading to very high localizd impacts.  They also damage the structure of bush clumps by browsing from the sides and exposing the interior to the forces of dessicating winds and erosion by water (Stuart-Hill 1992)." (Hoare et al, pp. 546-547)

     "Spekboom is browsed by all kinds of stock, cattle and goats in particular being very fond of it.  Cattle and large buck, such as kudu, have done great damage in spekboom country by tearing down branches, which are very brittle.  Spekboom was a favourite food of the elephant which once roamed parts of the Eastern province.  In difficult years it has been a great stand-by to farmers as it is extremely drought resistant, nourishing, and has a high moisture content.  Farmers claim that there are two varieties of the plant, the sweet and the sour, and that stock show a marked preference for the former.  Botanists, however, find no structural difference between the so-called 'sweet' and 'sour.'
     [Plants that grow on grow on an eastern or northern aspect are sweet and very well-grazed, while those on southerly or westerly aspects, or on shale are sour and not well grazed.  The latter contains much tannin.]
     "In parts, spekboom is eaten by people as well as animals.  Zulus eat the leaves raw.  In Portuguese East Africa, African [Khoisan] women are said to eat them when they are short of milk to feed their babies, as they increase the milk supply.  In the northern Transvaal Africans use the dry ground leaves in snuff.
     Portulacaria afra was one of "forty-seven plant species from 35 families [which] were recorded in the [June-July 2012] survey for the treatment of 11 different skin disorders" in the northern Maputaland area of KwaZulul-Natal province of South Africa (per De Wet, 2013).
     "In the dry Fish River Valley in the eastern Cape where there is no grass suitable for thatching, Africans sometimes use instead the stems and branches of the spekboom.  The dried stems are beaten with stones until flat and are then packed on top of each other to form a rather untidy but efficient thatch.  This is leading to the destruction of great numbers of spekboom in the valley.
     "Spekboom, which grows densely in its natural state as a tree, or as a bush often draping a hillside, is valuable for its soil-binding properties [and is planted in certain areas to assist in veld reclamation].  It also makes a neat clipped hedge for gardeners." (Palmer, pg. 568)

The leaves of Portulacaria afra (iGwanishe) and the tap root of Gazania krebsiana (iNongwe) are occasionally eaten as a thirst quencher or snack by the Xhosa.

By 1899 it had been exported to Algeria and Australia as a browsing plant for cattle and sheep.

"According to C.A. Smith (1966) there are two strains of the plant, the sour spekboom and the sweet spekboom, the latter practically eaten out of existence by all stock and wild antelope."

Per a comment in McCarthy's article, in Tucson, Arizona "[the collared peccary (aka javelina or musk hog, Pecari tajacu)] love, love, love to munch on [widely used landscaping] elephant food.  The stuff is irresistible to them and it's great fun to watch them in their ecstasy.  Sadly, a single band of hungry javelinas can completely demolish your elephant food in just a few minutes."

In the U.S., sparrows, magpies, squirrels, rabbits, and even a pet sloth are mentioned as liking the leaves of P. afra.  In India, captive long-tailed tree mice (Ploceus philippinus) have been observed as occasionally eating the leaves.

In tropical and subtropical areas (as close as the Mediterranean Sea), P. afra is suitable as a hedge plant, with a single plant reaching 7 feet (2.1 m) high and 8 feet (2.4 m) wide.

The value of the plant for fodder precludes its use as a valuable source of paper pulp.

So far there does not seem to be any significant or noteworthy use of P. afra as livestock feed in the USA.

The leaves have a slight but pleasantly acrid flavor.  It has been compared to anywhere from a lettuce taste to that reminiscent of a green apple.  Repeated tests over the years by RJB has shown no ill effects from eating even a handful of freshly-cut pads and green stems on an empty stomach.  Several acquaintances have had tastes of fresh pads and no problems have ever been reported.  The soft foliage is relatively low in protein, with a moisture content that ranges up to 80 percent.  Per http://www.fao.org/ag/AGA/AGAP/FRG/afris/Data/430.HTM, "Its leaves are edible and full of vitamin C..."  Other nutritional composition of the leaves is as follows:

As % of Dry Matter

Part
Crude Protein
Crude Fiber
Ash
Crude Fat
Carbohydrates
Ca
P
Fresh leaves, South Africa
11.8
14.6
11.8
3.9
57.9
2.87
0.35
Fresh aerial part, 30 cm high, Kenya
10.7
11.9
19.1
3.8
54.5
1.40
0.12
Hay, Zimbabwe
8.5
20.9
9.8
3.8
57.0
n/a
n/a

["Crude fat" = ether extract, "Carbohydrates" = nitrogen-free extract, most digestible portion of carbos; leaves per Groenewald, J.W. and D.M. Joubert; Proc. S. Afr. Soc. Anim. Prod.  Reprint, South Africa.  Department of Agriculture, http://www.fao.org/ag/AGA/AGAP/FRG/afris/refs/193.HTM, aerial parts per Dougall, H.W. and A.V. Bogdan; E. Afr. agric. J; 1958.  23(4):236, http://www.fao.org/ag/AGA/AGAP/FRG/afris/refs/129.HTM, and hay per Anon. Rhodesia agric. J.; 1934.  31:651, http://www.fao.org/ag/AGA/AGAP/FRG/afris/refs/19.HTM.]

A few recipes for spekboom can be found here.   Popular Cape Town restaurants like the Pot Luck Club use this succulent as accents to their beautifully crafted dishes.  This recent article explores the culinary characteristics of P. afra leaves.

(Its herbaceous cousin, purslane, Portulaca oleracea L., fresh and unprocessed, has been analyzed and found to be a fair source of calcium, phosphorus, and iron for humans.  Per http://www.e2121.com/food_db/viewherb.php3?viewid=89&setlang=, "Purslane contains large amounts of L-noradrenaline and dopamine and a small amount of dopa as well as vitamins B1, B2, and C, carrotene, potassium salts, glucose, cellulose, calcium, phosphorus, iron, etc.  Every 100 g of the edible part contains 2.3 g of protein, 0.5 g of fat, 3 g of sugar, 85 mg of calcium, 56 mg of phosphorus, 1.5 mg of iron, 2.23 mg of carotene, 0.03 mg of thiamine, 0.11 mg of ovoflavin, 0.7 mg of nicotinic acid, and 23 mg of vitamin C."  [Keep in mind that Portulacaria, however, may be further removed from Portulaca than many assume -- see Family level in TAXONOMY.]   The Zulus use an infusion of Portulaca quadrifida L. as an emetic.)


Per Beier, Paul  "SCB's Investment in Carbon Offsets, Frequently Asked Questions about the Baviaanskloof Megareserve Project, South Africa," Society for Conservation Biology Newsletter, Volume 14, Issue 4, November 2007:
     "The estimates of carbon storage are scientifically rigorous and highly conservative.  Data are particularly rich for Portulacaria afra (spekboom, elephant bush), which comprises up to 70% of the canopy in some stands of subtropical thicket.  Spekboom stores two-thirds of its carbon in soil and litter; both the living tissues and litter are highly fire-resistant.  Some local farmers restored areas to spekboom during the past 30 years, and scientists have sampled these sites to estimate directly the trajectory of carbon storage.  Although this empirical time series is available only for some aspects and slopes, the data provide a valuable adjunct to estimates based on plant diameter and height.  For purposes of the SCB contract, we estimate carbon storage per hectare based solely on spekboom.  Thus, we conservatively estimate the actual amount of carbon likely to be stored by multiple species.  Basing the estimate on spekboom alone is appropriate because spekboom will be the first species planted, and it is the only species for which detailed multifactorial trials have been conducted to maximize survival of outplanted cuttings.
     "In a worst-case scenario, spekboom may be the only species to reestablish on some sites.  The difference in carbon pools between intact and degraded thicket depends on the thicket type and the magnitude of past conversion.  There are 112 recognized thicket types, each with a different percent cover of spekboom.  Also, carbon leakage from the soil is positively correlated with lag since conversion.  Spekboom should store four tons of carbon per hectare per year, or about 10-15 tons of carbon dioxide emissions per hectare per year...
     "The 30-year old plots (above) include other native plants that colonized after the spekboom plantings.  Because the project would like to sell additional biodiversity benefits for restored subtropical thicket, they are committed to monitoring, learning how to recruit other species, and learning which species need assistance to recolonize a site.  In an ongoing experiment, spekboom plants are being inoculated with mistletoe[sic].  The mistletoe will attract birds, which in turn should defecate viable seeds of other plants into a spekboom stand.  It is hoped that low-cost measures like this can catalyze the process of assembling a fully-restored thicket.  Plans and greenhouse experiments are underway to restore some canopy-emergent plants [at the confluence of the Baviaanskloof and Kouga Rivers] expected to need assistance."


Per "spekboom soaks up CO2," submitted by sproutingforth on Tue, 2008-06-24 10:10 :
     "Rates of carbon storage by replanted spekboom were measured on a farm near Uitenhage.  About 27 years ago the farmer, Graham Slater, became tired of dealing with regular flooding of his barn and set about replanting the adjacent degraded hillslope with spekboom.
     "The two-metre-high growth of spekboom on bare ground under only 250mm to 350mm of annual rainfall was almost miraculous," said Cowling.  Each hectare of spekboom on the farm sequestered 4,2 tons of carbon a year."

Per "putting a cork in it," submitted by sprouting forth on Tue, 2009-01-27 11:14 :
     "...as part of Columbit Corks SA initiative to reduce their clients' carbon footprint by giving [spekboom] to wineries and producers who buy cork closures from them.
     "Columbit, who supplies packaging and processing to the wine, food and beverage industries in SA, has recently joined the UN Global Compact, a non-profit agency set up to guarantee sustainable growth and good corporate citizenship.
     "One of the ten principles the compact addresses is environmental responsibility.  To tackle this Columbit has set up a spekboom nursery in the Wellington winelands.
     "By giving their clients a spekboom to decorate their tasting rooms, Columbit hope to promote awareness of the spekboom's ability to absorb enormous amounts of carbon and why this is so important for the environment."

And per Salgado, Ingi  "Plankton experiment may create new hazards," Business Report, January 22, 2009:
     "Benny Mokaba, the head of the [Sasol] group's energy cluster, extolled the virtues of spekboom, a plant indigenous to the Eastern Cape that has attracted considerable attention among scientists for its potential to soak up carbon.
     "The group says that planting 100 000ha of the plant can offset emissions from the 80 000 barrel-a-day coal-to-liquid facility.
     "In the corporate imagination, ...plants such as the spekboom serve to buy business a little more time to continue making money for shareholders from carbon-polluting activities, while simultaneously spinning the line that alternatives are being sought."

     A South African gardening blog article with a variety of comments about uses for spekboom can be found at http://www.sprig.co.za/2009/02/how-cool-is-spekboom/.

     And there is this overview from May 2010 by a Belgium professor with an Australian connection.

     A recent article discussing the realities of these plans is This 'Miracle' Plant Is Supposed To Save The World.

     And then there is the possibility of phytoremediation of soil contaminated with hexavalent chromium using P. afra (in Spanish).

     Meanwhile, Shumaila Ijaz et al's recent article, "Investigation of bioactive constituents and evaluation of different in vitro antimicrobial, antioxidant, and cytotoxicity potentials of different Portulacaria afra extracts," in the February 2024 Journal of King Saud University - Science (Volume 36, Issue 2, 103033) has the interesting Conclusion that "Research is being done on the phytochemicals that have been extracted from P. afra since it has been utilized as a source for drugs that are currently available on the market.  It was determined that P. afra methanol extract has a significant potential to reduce oxidative stress based on the results of antioxidant assays.  The FT-IR analysis found various classes of phytochemicals, which are in charge of P. afra biological and phytochemical activity.  P. afra methanol extract has the highest level of phytotoxic potential.  Further, antioxidant, antibacterial, cytotoxic and phytotoxic assays constitute scientific underpinnings and elaborated the various characteristics of medicinally characterized plant that plays a crucial part in defense mechanisms and can be effective against infections.  Further research on the isolation and characterization of bioactive chemicals is still required in order to use them in the creation of drugs to treat wide a range of ailments."  The Abstract concludes with "The bioactive compounds found in P. afra extracts have antibacterial, antioxidant, and cytotoxic properties, revealing their ability to induce cell death in cancerous cell lines, indicating potential anticancer agents and making them intriguing candidates for future research and the possible creation of new therapeutics.  We advise the use of these extracts against biofilms as these extracts have shown significant antibacterial activity against gram negative bacteria."

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CONTAINERIZED

Larger trees will take full sun even in the summer in Sunset Zone 13, and can safely go without watering until the largest leaves start to show signs of wrinkling/dehydrating.  This occurs at first along the inside of the outer edge along the perimeter of the leaf, and then continues width-wise.  Young leaves receive preferential nourishing by the plant and so rarely become dehydrated.  If a specimen has both old and new dehydrated leaves, it may have been too long without water to continue to survive.  Leaves becoming crisp and brown before falling off are a sign of the plant being too dry for too long. 

Leaves of plants grown in full sun are smaller than those of the same variety grown in partial shade.  Full sun is also known to bleach the leaves to a pale yellowish color on some large potted specimens.  Brown patches on leaves can be due to sun scorch.  Move the affected plant to a more airy place and shade from the hot sun for two weeks.  Then, move back gradually over a period of two more weeks.

Too much water and/or fertilizer will cause leggy growth (up to 3 cm between nodes), as also will not enough full exposure to sunlight.  P. afra appears to survive in almost any soil mix, and can go for several years without repotting.  It responds rapidly with improved color to moderate fertilizer or chelated iron.  A suggested fertilizing schedule using a balanced formula (e.g., 20-20-20) is weekly during the growing season(s), monthly during slow-growth times, none at all during winter.  A soil mix recommended in South Africa is three-quarters gravel or sharp stone and one quarter well-composted friable cow manure ("Krall" manure, dried and orderless).  Also recommended is a good loam-based No. 2 potting compost, or a soil-less compost, with 30% coarse, gritty sand.

Prune by pinching or cutting above a pair of pads.  In moderate to high temperature climates, a new bud will start within a week or two from the juncture of each of the pads, lighter green in color and emerging 90 degrees from the old leaves.  Several times new leaves have been observed arising from a previous pair which was only 2 mm in length, although usually the older pair is larger.  The new pair can be removed successfully as early as their bud is large enough to be plucked off using fingernails, approximately 2 or 3 mm long and not yet opened into a pair of leaves.  A new bud can arise from the base of a leaf before that leaf falls off.  Pruning above an older pair of leaves may result in a new bud at only one of them, and usually less quickly than if the pruning is done above a younger pair of leaves.  If only one leaf of an existing pair is removed, the resulting new growth just is less symmetrical.  However, leaving a stub of more than 1 or 2 mm in length, especially on older stems, can either delay or inhibit the growth of one or both of the new side buds. 

Correspondant Susan Marsh (4 Feb 2011) tells us that she uses "partial defoliation to control branch size -- a defoliated branch does indeed slow down in growth (haven't had one die yet) compared to the rest of the plant.  I also use defoliation on the crowns of plants a lot, the crowns grow faster than the rest and have to be kept tamed down to allow the lower branches to get size on them for bonsai."

Adventitious buds can freely arise at nodes on old wood if the bark is intact there.  The timetable for this is highly variable and could extend into over a year before budding occurs if it is going to do so.  Wherever a bud or branch has been removed along a branch or the trunk a new bud could sprout. 

The non-budding stump of a cut-off large branch will eventually dry up and fall off by itself.  Branch stubs under 1.3 cm in length dry out and eventually will break off.  A bud may arise at the base of this at any time before or after separation.  The ends of stubs that are yellowish-brown to blackish-brown in color may have a slight non-spreading fungus.  It is recommended to keep the base of the plant free from litter build-up.  Larger stubs probably don't need special treatment or coverage, other than to not be directly watered (which might promote fungal growth).  The bark of the lower trunk and roots may get discolored with whitish, yellowish or brownish buildup from hard water deposits/mineral salts.  Leaves will also show hard water film if wetted directly.

Resembling a succulent, it was not considered able to be shaped into a bonsai as defined by the traditional Japanese school of the art.  However, extensive experience in the West (especially by the late artist Jim Smith of Florida) has caused this to be acknowledged as a suitable specimen and very acceptable "artistic pot plants" can result from trained P. afra.  Smith's first bonsai was a Portulacaria that has been in a pot since 1957.  Informal upright or cascade are the two easiest styles in which to grow it.  Formal upright, root-in-rock, raft, slanting, and grove are a few of the other successful styles into which this plant has been successfully designed by enthusiasts outside of Japan.

Use caution when wiring as the branches and leaf pads break easily.  It has been recommended to let the plant go without watering for a period before wiring so that the branches will then be more flexible.  It is also recommended to leave the wire on to the point of apparently scarring the tree.  Once the wire is removed, the branch will bulge back into shape without disfigurement.  Branches can also be shape using tie downs, spacers, and weights. 

Because of the nature of the thin skin and bark wood, the techniques of jin -- a weathered deadwood branch or apex -- and shari -- deadwood and/or hollow section along the trunk -- are not advised.

It can be used as an Indoor Bonsai where sunlight or strong artificial light is sufficiently available.  While lack of humidity is a plus for indoor specimens, good air circulation is still important.  During the growing season, monthly feeding with a balanced (20-20-20) fertilizer is recommended.

Insufficient longer-term -- approx. 6± months -- light indoors will result in pale green leggy and brittle new growth, drying and shriveling of older pads, and drying, shriveling and loss of smaller branches.

Recommended pot colors include complimentary brown, gray, red or contrasting dark blue.

Examples of Portulacaria as bonsai around the world can be found here, as well as this storehouse of wild and domesticated images.

It is said that Crassula jade branches can fuse together after a period of time, but Portulacaria jade branches won't.  If P. afra are braided together like is sometimes done with Ficus, current best evidence is that the dwarf jade branches will never truly fuse.

This dwarf jade bonsai workshop video from Pakistan, as well as this listing of YouTube videos featuring Portulacaria afra.

Per a Facebook posting caption 24 Mar 2019 by Mel Carrillo, "My [cascade-style] Portulacaria exhibited at the 62nd Annual California Bonsai Society Exhibit [this week-end].  This was the first time this species was accepted for exhibition."

A blog article by bonsai artist Moshe Emergui can be found here, and another, by Kaizen Bonsai, here.

* * * On Facebook there is now a Portulacaria Afra (Dwarf Jade) Bonsai Study Group which can be accessed by application only.  Much information and varied displays can be found throughout the posts here from around the globe since the group was started June 9, 2017.
And the Spanish-language Facebook group Portulacaria Afra Bonsai latinoamerica was started April 24, 2020.

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Bibliography
Part 5



This ongoing monograph was begun in the summer of 1993,
at a time when Portulacaria afra was seemingly the only bonsai that would survive for me in the Phoenix area,
and was then first put on this web site in early July of 1999.
This page was last updated 21 January 2024.
If you have comments or thoughts concerning this, please e-mail me, rjb@magiminiland.org


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