Care Diary: Aloe aculeata

aloe aculeata

Written ByJen Greene

Posted: September 2, 2021

I admittedly have an obsession with the aloes I’ve seen at the Safari Park that look like, as my brain likes to call them, “Dinosaur Skin”. The ones at the Safari Park are huge, but the texture seems to occur in a handful of species. I’ll be talking about one of my favorites in this care diary: Aloe aculeata

Aloe aculeata is what I’d call a mid-sized aloe compared to a lot of the more landscape-friendly species that are available. They’ll max out at just over 3 feet tall, and about 3 feet wide.

Leaves are long and fairly broad, curving upward to give the aloe a rounded appearance. They have teeth on both sides of their leaves, with a pale base and a dark brown or black sharp point. Some forms do not have the pale base, but most Aloe aculeata you find in the US will be a type that has the white/pale bottom of the spines. 

Blooms with a single inflorescence in younger plants, and as they gain age and size, the blooms will split into as many as 4 separate bloom stalks. Blooms range from yellow to orange or a mix of the two.

Aloe aculeata

Aloe aculeata is not a threatened species, and can be found in multiple parts of the Limpopo Province and the most northern part of Mpumalanga. They can be found further north up into Zimbabwe. Prefers rocky areas, grassland, or bushveld, between 1500 and 5600 feet above sea level. 

aloe aculeata black spine

Due to the size of more mature plants, I use mine primarily as landscaping plants rather than potted specimens. 

I will typically start younger or imported plants in a pot until they are clearly outgrowing their container, and then plant them in-ground with consistent water for the first few months. 

Once they gain some size, they are quite drought resistant in-ground, and are excellent as a sculptural landscape aloe.

Care for Aloe aculeata

Part of why I love these aloes so much is that they are incredibly hardy and practically indestructible once established. If you’re in zones 9 or 10, these are easy wins for your garden. You may be able to grow them outdoors even in zone 8, but you should expect to cover them with a frost cloth and provide plenty of ground cover to prevent them from experiencing a hard frost (which they won’t survive). 

Lighting and Water

As with most cacti and succulents, Aloe aculeata‘s water needs are very closely tied to lighting (and warmth). During warmer weather, they’ll accept plentiful amounts of water, particularly if they are planted in ground in an area with good drainage.

My in-ground plants are on a rocky slope, and usually have dried out completely within 2 to 3 days of being watered. In pots, so long as they can dry out before you water them again, they’ll thrive.

The great thing about these aloes is that once they are established, they can tolerate quite a bit of water deprivation before they suffer significant ill effects. Happy, well-watered aloes will be bright green and have an open rosette, looking almost wide and flat if they are kept permanently well-watered.

When kept on the dry side, the tips of the leaves will tend to point towards each other. The thirstier the aloe gets, the more the plant will resemble a tear-drop shape. Plants that are both thirsty and kept in bright light will begin to blush an orange-tan color, even becoming almost red when extremely stressed. When they do become highly stressed in this way, simply dumping a bunch of water on them once won’t be enough to help them rebound. Instead, consistent watering for several weeks or even months is likely to be needed.

For potted Aloe aculeata, you should water when you’re confident the entire pot is dry, and water thoroughly so you can saturate all of the soil in the pot each time. Potted plants will show signs of water and/or sun stress much faster than those planted directly in-ground. 

aloe aculeata

My oldest aculeata after a heavy rainstorm a few days ago (Sept 2021). The rosette has relaxed and oepend up, and the leaves are quite plump. 

aloe aculeata crousiana

A stressed juvenile Aloe aculeata var. crousiana; showing the tightly curved in leaves and brown/red blushing on the outer leaves. With more water and protection from sun, the newly emerging leaves are bright green. 

Soil and Pot Size 

When selecting an in-ground site to plant your Aloe aculeata, look for soil that drains well and/or is on a slope, so the roots don’t sit in damp soil or saturated ground for extended periods of time. Their roots are quite extensive, and these aloes can work very well as a form of erosion control for hills, particularly when paired with smaller species or creeping succulents. 

If you need to move your aloe after planting it, you can do so with little impact on the plant as long as it’s within the first month or so. I transplanted my oldest aculeata after two years in its initial spot by digging about 6″ around the leaves and going a foot deep under the plant. Any roots outside of that root ball were severed, and I shook off most dirt before moving it to its current spot on a west-facing slope behind our house. It took a few months to fully bounce back, but has thrived in the new location, even blooming on schedule. 

When potting an Aloe aculeata, a standard succulent soil mix is perfectly acceptable. I prefer to mix in an additional 25 – 50% pumice if it’s an overly organic blend, such as miracle gro, but if you’re using a quality mix then you should need little in the way of soil amendment. 

These are aloes that appreciate a considerable amount of space for their roots, particularly if you are trying to grow them to true specimen size. If growing in a pot, ensure that they are not overly root bound and expect to repot them yearly while they are still growing. I prefer to raise mine to a size where they’re ready to outgrow a 6″ pot and then planting them in-ground at that point. 

For those in colder climates who plan to keep them in pots year-round, expect to need a 1 – 3 gallon sized pot for a mature plant. Experienced growers could likely get away with a smaller pot size, but more room for the roots is more likely to result in an impressive specimen plant if you’re unsure of what the aloe needs. 

Growth Rate

Aloe aculeata grows at a steady pace when provided the conditions it prefers. I picked up my largest specimen initially as a specimen growing in a 4″ pot in late 2018. I transplanted it to a 1 gallon pot and let it grow for about 8 months, and then planted it in-ground (pictured right) in July of 2019.

While labeled as “black spines”, when compared to my other aculeatas, the colors are nearly identical, so maybe it was a marketing spin or hype from the original grower. As seedlings, they often all look similar, and it’s only as the plants mature that you can see specific morphological differences.

In early 2020, this plant had produced its first bloom spike!

Aloe aculeata black spines
aloe aculeata bloom

My other Aloe aculeata plants are very close in size to where this one was when it bloomed, so I’m hopeful this winter I’ll be able to set true species seeds.

The original bloom spike was entirely orange, and as the flowers opened they were a pale orange to yellow color. 

The full bloom event took about 3 weeks from the flowers becoming visible, to opening, to the top of the stalk actually opening up. 

Later in 2020, I ended up digging it up and moving it to the slope where it now resides. In just over a year, it’s nearly doubled in size, so the move was a good one! The warmth, increased sunlight even during hot days, and weekly watering seems to have had a strong impact. The front area where it was planted before was shaded from around 2 or 3 pm onward – perfect for succulents, not so great for high-light loving aloes.

Within a month or two of being transplanted, my Aloe aculeatas had bounced back fabulously and were thriving. Through winter, I watered them only a handful of times, letting natural rainfall take care of the rest. They did fine through some light frost, with little to no damage on leaves aside from some old ones getting tip damage.

When planting on the slope, I used a few large rocks to wedge at the low side of where they were planted. This acted as a ledge for water and soil retention, and has done exactly what I hoped in terms of keeping water from running straight down the hill instead of soaking in by the root base. 

aloe aculeata half grown

Through winter, my aloes on that back slope did well even during times of light frost and an extremely unusual hail storm. I have frost cloth on hand for particularly cold nights, but they have seemed to do fine even with night time drops to the high 20s. A key part seems to be plant maturity and size; I am sure the roots die back somewhat in winter when it is cold and wet from rain, but having a large plant body and robust root system means they can compensate for any loss they experience. 

These are super rewarding and very enjoyable aloes to grow if you have the space or yard to accomodate them! While not as prolific of bloomers as other species, they are quite eye catching in the garden as they are, and I highly recommend snagging one or five when you get the chance. 😉 

You may also like…