How to Grow the Medicinal Aloe Arborescens

Aloe arborescens, also know as the tree aloe, torch aloe, candelabra aloe or krantz aloe, is a hardy succulent perennial plant from the Aloe family Asphodelaceae, which is native to the south-eastern coast of Africa (Botswana, Malawi, Mozambique, South Africa, and Zimbabwe).

This drought-tolerant succulent prefers to grow in sandy or rocky well-drained soil. It is usually found growing along exposed ridges, cliffs and rocky outcrops in mountainous areas, but is well adapted to grow anywhere from mountain tops all the way down to sea level, and even in habitats such as dense bush and coastal forests. Being salt-tolerant, this Aloe can tolerate coastal conditions.

Is Aloe arborescens Better Medicinally than Other Aloes?

The medicinal value of Aloe arborescens is recognised across many cultures, as it’s a very popular traditional medicinal plant in South Africa, Asia, Russia, Italy and Japan, but there has been renewed interest after it was found that Aloe arborescens contains higher concentrations of active medicinal constituents than other Aloe species, including Aloe vera.

Some sources claim both the gel and latex of Aloe arborescens contains three times more of the active compounds than Aloe vera does, which is quite significant.

Most people are familiar with the use of Aloe vera gel for the relief of skin conditions such as burns, bites, itches and scratches, but the medicinal compounds in Aloe plants offer a lot more value than that.

The active constituents in Aloe leaves have been reported to show antibacterial, antimicrobial, antitumor, anti-inflammatory, anti-arthritic, anti-rheumatoid, anticancer, and anti-diabetic activities. They have found use in treating constipation, detoxification, and supporting immune system deficiencies. Clinical trials have validated the use of Aloe gel as a wound and burn-healing topical agent, and as an anti-hyperglycemic for use in managing diabetes.

If Aloe arborescens contains greater concentrations of active compounds, then why is Aloe vera barbadensis Miller preferred commercially?

The simple reason is that the narrower leaves of Aloe arborescens contain less gel, which leads to lower production yields, and since they also contain more of the bitter compound aloin in their latex, this can make the gel taste more bitter, which is undesirable.

Which Aloe Varieties are Edible?

According to the article “Aloe vera: a valuable ingredient for the food, pharmaceutical and cosmetic industries–a review” published in the journal Critical Reviews in Food Science and Nutrition in 2004, to date only six to seven species of the Aloe family have been consumed by human beings as functional foods or pharmaceuticals, and these include:

1. Aloe vera Linne
2. Aloe barbadensis Miller
3. Aloe arborescens Miller (Tree Aloe, Torch Aloe, Candelabra Aloe, Krantz Aloe)
4. Aloe saponaria Haw (babosa pintadinha)
5. Aloe perryi Baker (Socratine Aloe)

Its inclusion in this list indicates that Aloe arborescens can be used internally, but keep in mind that it yields less gel and higher concentration of the bitter aloin compound in the latex, which may be a consideration when the gel is sought rather than the medicinal compounds in the latex.

Identifying Aloe arborescens

Aloe arborescens is a large, sprawling, bushy succulent shrub that grows to a height of 2-3m (6-9‘) and a similar width. It is described as a multi-headed shrub because it has a thick central woody trunk with many branches, much like a candelabra in shape, hence its common name.

The long, thin, succulent, sword-shaped leaves are grey-green in colour, or green with a slight blue tint, and are lined with pale teeth along the leaf margins. These striking leaves are arranged in attractive rosettes (circular arrangements of leaves at a single height) at the ends of the branches, and they curl backwards down towards the base of the plant. The individual rosettes grow to around 45cm (18”) wide.

During the cold winter months, the rosettes bloom, producing tall, colourful, torch-like flower spikes which are usually unbranched, with two or more flower spikes arising from a single rosette.

The flowers are large clusters of vibrant red-orange tubular flowers arranged in a conical arrangement around the flower stalk, and in botany this type of inflorescence known as a raceme.

As is the case with all Aloe plants, the flowers produce nectar and they attract bees, as well as birds such as hummingbirds and sunbirds if they are native to your country.

How to Grow Aloe arborescens

It doesn’t take much effort to grow Aloe arborescens. It’s a fast growing plant which will cope with very dry locations and tolerate neglect once it is established. It thrives in warm temperate to subtropical climates, and can withstand moderate frost down to -4°C (25°F).

Soil – Will grow in a wide range of soils, prefers well-draining soils with a loamy soil texture, enriched with compost, with a soil pH 7.0 to 8.5.

Light – Prefers full sun but will tolerate light shade.

Watering – Infrequent, don’t water in winter.

Feeding – Feed in spring using a slow-release fertiliser that is low in nitrogen, or use a specific cactus and succulent fertiliser. Don’t overfeed as these plants grow in harsh environments with low nutrient levels.

Growing Aloe arborescens in Pots and Containers

This Aloe can be grown perfectly in pots and containers, and this will keep the plant down to a manageable size, whether you choose to grow it outside or indoors. Use a larger pot as the plant is fairly fast growing and will need the space, but don’t overpot it too early as the potting mix will stay wet for too long if the pot is too large for the plant, and that will lead to root rot.

When planting an Aloe in a pot, it’s preferable to use a well-draining commercial cactus and succulent potting mix, but if that’s not available, you can mix your own by combining equal parts of coarse sand, perlite, and potting mix, or even 2/3 potting mix with 1/3 perlite will do the job.

Place the pot in a sunny location, and water sparingly. Allowing the potting mix to dry out between deep waterings in the warmer seasons. Don’t water at all in winter, and if the pot is located outdoors, try to keep the plant a bit drier by placing it in a location where it won’t get waterlogged by cool season rains. Under the eaves of the house (the overhanging roof) is a good place to keep succulents and cacti a bit drier in winter.

Don’t ever sit the pot in a saucer of water. If a saucer is used underneath the pot, elevate it using pot feet, some stones or a paver so the Aloe roots don’t get waterlogged!

How To Propagate Aloe arborescens

Aloe arborescens is easily propagated from sideshoots, stem cuttings and seeds.

• The sideshoots or pups are new young plants growing from the base, these can be carefully removed with as much roots as possible and transplanted in spring.
  
• Stem or branch cuttings can be taken in spring. First remove the lower leaves from the cutting, then allow the cutting to dry for a day or two until the wound has sealed. Next, plant the cutting in a small pot filled with sand or a well-draining cactus and succulent potting mix. Water very sparingly, and don’t overwater as the cutting will rot if the potting mix is too wet.
  
• Sow seeds in spring, they should take three to four weeks to germinate. Protect the seedlings from early spring frosts. Be aware when using seeds that Aloe arborescens hybridises readily with other aloes, don’t use seed for propagation from plants flowering when other aloes are flowering at the same time.

Suggested Uses of Aloe arborescens

Here is a list of possible uses for this very versatile plant:

• This plant can be used to create a dense fire-retardant hedge in fire-prone areas, as the leaves don’t burn, and any wind-blown embers will be caught by the dense leaves and extinguished.
  
• A dense, spiky, fast-growing and tall Aloe can also be used as an impenetrable barrier plant, which is also deer-proof.
  
• Being able to grow of the edges of cliffs in exposed locations, this plant can be used to hold soil together on slopes and edges to prevent soil erosion.
  
• A stunning, low maintenance, winter-flowering plant which can serve as a nectar source for bees and birds is a great addition to a garden.
• The interesting plant form lends itself to be used as a decorative indoor floor plant for a bright, sunny location.
  
• As a medicinal plant, the antibacterial and anti-inflammatory gel from the leaves of Aloe arborescens can be used on the skin to relieve burns, assist with the healing of wounds, and ease irritation. The leaves can be split or crushed fresh to extract the gel.

You might also like these other articles on Aloe vera plants:

• Identifying and Growing Edible Aloe Vera
• Why Is My Aloe Vera Plant Turning Yellow and Brown?
• How to Make Aloe Vera Gel from Fresh Aloe Vera Leaves

References:

• Hankey.A & Notten.A (2004) Aloe arborescens Mill. – South African National Biodiversity Institute (SANBI). PlantZAfrica
• Eshun K, He Q. Aloe vera: a valuable ingredient for the food, pharmaceutical and cosmetic industries–a review. Crit Rev Food Sci Nutr. 2004;44(2):91-96. doi:10.1080/10408690490424694
• Bera, Tushar. (2018). Phytochemical Constituents of Aloe Vera And Their Multifunctional Properties: A Comprehensive Review. International Journal of Pharmaceutical Sciences and Research. 9. 1416-1423.. 10.13040/IJPSR.0975-8232.9(4).1416-23.
• Ro HS, Jang HJ, Kim GR, Park SJ, Lee HY. Enhancement of the Anti-Skin Wrinkling Effects of Aloe arborescens Miller Extracts Associated with Lactic Acid Fermentation. Evid Based Complement Alternat Med. 2020;2020:2743594. Published 2020 Jun 2. doi:10.1155/2020/2743594
• Salehi B, Albayrak S, Antolak H, et al. Aloe Genus Plants: From Farm to Food Applications and Phytopharmacotherapy. Int J Mol Sci. 2018;19(9):2843. Published 2018 Sep 19. doi:10.3390/ijms19092843
• Boudreau M.D., Beland F.A. An evaluation of the biological and toxicological properties of Aloe Barbadensis (miller), Aloe vera. J. Environ. Sci. Health C. 2006;24:103–154. doi: 10.1080/10590500600614303.
• Rahmani A.H., Aldebasi Y.H., Srikar S., Khan A.A., Aly S.M. Aloe vera: Potential candidate in health management via modulation of biological activities. Pharmacogn. Rev. 2015;9:120–126. doi: 10.4103/0973-7847.162118.
• Radha M.H., Laxmipriya N.P. Evaluation of biological properties and clinical effectiveness of Aloe vera: A systematic review. J. Tradit. Complement. Med. 2015;5:21–26. doi: 10.1016/j.jtcme.2014.10.006.
• Nejatzadeh-Barandozi F. Antibacterial activities and antioxidant capacity of Aloe vera. Org. Med. Chem. Lett. 2013;3:5. doi: 10.1186/2191-2858-3-5.
• Jain S., Rathod N., Nagi R., Sur J., Laheji A., Gupta N., Agrawal P., Prasad S. Antibacterial effect of Aloe vera gel against oral pathogens: An in-vitro study. J. Clin. Diagn. Res. 2016;10:ZC41–ZC44. doi: 10.7860/JCDR/2016/21450.8890.
• Athiban P.P., Borthakur B.J., Ganesan S., Swathika B. Evaluation of antimicrobial efficacy of Aloe vera and its effectiveness in decontaminating gutta percha cones. J. Conservat. Dent. 2012;15:246–248. doi: 10.4103/0972-0707.97949.
• Boudreau M.D., Mellick P.W., Olson G.R., Felton R.P., Thorn B.T., Beland F.A. Clear evidence of carcinogenic activity by a whole-leaf extract of aloe barbadensis miller (Aloe vera) in F344/n rats. Toxicol. Sci. 2013;131:26–39. doi: 10.1093/toxsci/kfs275.
• Grundmann O. Aloe vera gel research review: An overview of its clinical uses and proposed mechanisms of action. Nat. Med. J. 2012;4:9.
• Thamlikitkul V., Bunyapraphatsara N., Riewpaiboon W., Theerapong S., Chantrakul C., Thanaveerasuwan T., Nimitnon S., Wongkonkatape S., Riewpaiboon A., Tenambergen E.D. Clinical trial of Aloe vera linn. For treatment of minor burns. Siriraj Med. J. 2017;43:4.