Aloe marlothii [AL-oh, mar-LOTH-ee-eye] is a large evergreen succulent plant type native to Botswana, Mozambique, Swaziland, the Republic of South Africa, and Zimbabwe.
As with many other plants in the Aloe plant genus, this species is being studied for a range of medicinal uses.
Aloe marlothii (mountain aloe) gets its common name from the plant’s ability to thrive in mountainous regions but is also known as flat-flowered aloe (due to the distinctive horizontal branches) and spiny aloe.
Meanwhile, the species is scientifically named after German botanist Hermann Wilhelm Rudolph Marloth.
As with all aloe species, mountain aloe hails from the family Asphodelaceae (sub-family Asphodeloideae).
Mountain aloe stands apart from its relatives due to its robust appearance and bright flowers.
Its thick greyish-green leaves taper from a broad base to a sharp point and can grow up to 5’ feet long in a dense rosette.
In more humid areas, the leaves may appear as a more vibrant green.
Old leaves remain draped from the stem to form a skirt or petticoat adding to the robust appearance of this plant.
The reddish-brown spines on this plant even on the lower surfaces start off dense and thin out with age.
They run down the margins of each leaf, but also appear randomly across the fleshy parts.
Aloe Marlothii Care
Size & Growth
Mountain aloe has a slow growth rate, achieving a maximum height of 8’ to 10’ feet tall, with a spread of up to 6’ feet wide.
It thrives in USDA hardiness zones 9-12.
Due to the withered skirt and spread of its rosette, this plant has a well-rounded appearance, even at full height.
Because of this, these plants usually need a spacing of 6’ feet to achieve optimum growth, although it may share this space with smaller plants in a complimentary garden.
Flowers and Fragrance
Flowers tend to bloom in late fall to early winter.
These comprise of a panicle containing as many as 30 racemes which tend to grow mostly horizontal.
The inflorescence of Aloe marlothii is a striking bright red, orange-yellow, or yellow flower color.
The plant is known to attract both songbirds and hummingbirds, adding even more beauty to whatever space it’s planted in.
Light & Temperature
This plant requires full sun to stay healthy in the garden.
Despite this, its native mountainous habitat allows it to withstand temperatures as low as 15° degrees Fahrenheit (-9° C).
As a result, Aloe marlothii is best suited for heat zones 10-11 and most climate zones 8-9 and 12-24.
Related: The Differences In Aloe vs Agave
Watering and Feeding
When first planting or transplanting Aloe marlothii, the plant should be watered once per week for the first month, then weaned off.
As with many succulents, a well-established mountain aloe is capable of surviving without water for several months, making it a perfect choice for regions prone to drought.
Excessively inflated leaves are a sign of overwatering, which can lead to rot if not addressed.
Conversely, leaves having dulled or are too thin are a sign the plant isn’t getting enough hydration.
Aloe marlothii prefers a warm, wet summer and dry winter due to its native monsoon seasons.
Soil & Transplanting
Aloe marlothii thrives in a wide range of soil types, preferring sand or loam and able to handle acidic, alkaline, and neutral pH soils equally well.
Too much clay or density in the soil may result in overwatering.
Rockeries are an excellent choice, as the extra radiated heat benefits this aloe plant in cooler climates.
A good potting mix to use in relatively damp regions is one part compost and one part river sand to every two parts of heavy clay soil.
Especially arid environments may benefit more from undiluted soil density, as this will retain water for longer periods.
However, adding bone meal can help reduce the risk of rot.
Grooming and Maintenance
Mountain aloe is a low-maintenance plant, requiring very little maintenance or additional watering once in the garden.
The withered leaves form a natural petticoat and thus do not need to be pruned away.
More Varieties Of Aloe
- Aloe Arborescens – Candelabra plant
- Aloe Aristata – Lace Aloe
- Aloe Cameronii – Red Aloe
- Aloe Ferox – Cape Aloe
How To Propagate Mountain Aloe
Aloe marlothii is easy to grow from seed when planted in a container with drainage holes in the bottom.
Place a layer of stones and cover with a small amount of compost before adding sterile soil.
River sand also works well.
Seeds may be sown directly onto the sand with thin sand covering.
Mist the container and store it in a place with direct sunlight.
Water each morning to afternoon, reducing frequency after germination.
Regular care will result in faster growth.
The seedling may be transferred to a pot with more loamy soil over stone chips and compost at any point between three months and two years of age.
Mountain Aloe Pest or Diseases
Mountain aloe is a most resilient plant, being tolerant of deer, drought, and most diseases.
Overwatering this plant can lead to rot.
The plant is known to be susceptible to white scale and aloe rust fungus.
Mealybugs, mites, scale insects, and snout beetles are all potential threats.
In its natural environment, mountain aloe uses the wind to propagate.
As such, this plant may spread easily throughout your garden.
Any saplings sprouting may be removed with little effort, preventing this species from becoming invasive.
Suggested Aloe Marlothii Uses
Aloe marlothii are perfect succulents for living pillars and their winter inflorescence makes great accents for a Mediterranean, cottage, or rock garden.
Being drought-tolerant, this spiny tree aloe alone with Agave has been promoted as part of efforts to encourage low-water gardening in California.
Traditionally, they were used by the Zulu to treat roundworm and neighboring cultures used it as an ingredient to alleviate stomach issues.
These benefits are not yet confirmed.
Mountain aloe has been part of medical studies involving dermal permeation and anti-erythema in humans, as well as tests on anti-tick treatments for cattle, promising several medicinal uses with more effectiveness than aloe Ferox.