Cape Aloe: Otherwordly Tree Aloe

If you’re looking for a large, dramatic succulent that also adds color to your garden, check out Cape aloe. This unusual aloe grows tall and puts out branched candelabras of vivid flowers every winter. Here’s how to grow this South African native as a desert landscape plant.

Most aloes grow as rosettes that are about as tall as they are wide, but a few grow tall and tree-like. Of all the tree aloes, Cape aloe (Aloe ferox) is the species most commonly grown as a southwest desert landscape plant.

When young, its thick blue-green leaves form a symmetric rosette. At this stage, it looks like a typical aloe. But over time, it starts to look like a mutant palm tree that escaped from Jurassic Park!

It grows tall (up to 10 feet!) and develops a single trunk. Leaves have weird, knobby spines. The number of flower stalks increases. Plants usually send up 4 to 8 stalks at a time, but can have even more.

Every winter, their wild-looking candelabra flower stalks add vivid color to winter gardens, and attract bees and hummingbirds. The tubular flowers are usually orange-red but can range from yellow-orange to bright red.

Why I Like This Plant

Dramatic specimen plant
Adds vivid winter color
Low maintenance
Attracts bees, hummingbirds
Deer, rabbit, javelina resistant

Things to Watch Out For

If you’re used to growing aloes in containers, or you grow aloe vera or ‘Blue Elf’ aloe as landscape plants, the size of cape aloe can come as a shock. It can ultimately reach 6 to 10 feet tall with 4 foot flower stalks.

Cape aloe is more prickly than many other aloes, too. It was given the name ferox (which means “fierce” or “warlike”) for a reason! This refers to its sharp edges and knobby spines that dot leaf surfaces.

Optimal Growing Conditions

If you’re thinking of adding a cape aloe to your garden, you need to find a suitable place that will keep your plant healthy and looking good… while minimizing maintenance for you.

Here are the key factors to keep in mind.

Temperature

Cape aloe should be grown in USDA Hardiness Zones 9 – 11. It tolerates most summer heat, but struggles when the temperature exceeds 115℉. For this reason, it’s not commonly grown in hotter areas like Phoenix.

It can survive cold down to 20℉ but may experience damage when the temperature dips below 25℉.

Sun Exposure

Cape aloe can be grown in full to part sun. It appreciates relief from fierce afternoon sun during the hottest months.

Size and Growth Rate

Cape aloe can ultimately reach a mature size of 6 to 10 feet tall by 3 to 5 feet wide. When in bloom, flower stalks can add an extra 2 to 4 feet in height.

Soil

Cape aloe can be grown in any native desert soil, but it prefers sandy or rocky well-draining soil.

Other Location Considerations

This is one large aloe! If space is a problem, consider growing one in a large container, which will keep its size in check. Make sure your pot has good drainage and use specifically formulated cactus soil.

Cape Aloe:
The Essentials

Common Name	Cape aloe
Scientific Name	Aloe ferox
Origin	South Africa
Plant Type	Evergreen succulent
USDA Zones	Zones 9 – 11
Cold Hardiness	To 20℉
Flower Color	Orange-red
Flower Season	Winter
Mature Size	6-10′ high x 3-5’ wide
Growth Rate	Slow
Sun Tolerance	Full, part sun
Water Needs	Low
Pests & Diseases	Root rot
Garden Friendly	No litter, non-toxic
Wildlife	Attracts bees, hummingbirds

How to Plant

To plant a cape aloe, dig a hole the same depth as the root system and twice as wide.

It’s generally recommended that you not add amendments to the soil. However, good drainage is critical, so if your soil drains slowly, amend with coarse sand or small gravel until you have a loose, well-drained mix.

When to Plant

Most landscape succulents (cactus, agave, etc.) should be planted in the spring, but winter-blooming aloes are an exception. They do most of their growing in the winter and establish best when planted in the fall.

How to Care for Cape Aloe

Whether you’ve recently planted a cape aloe or have an existing plant in your yard, here’s how to take care of it to keep it healthy and looking its best.

How to Water

You’re probably used to giving a plant a good soaking immediately after transplanting, but that isn’t the best practice with aloes and other succulents. Counterintuitively, it’s best to not water aloes for one to two weeks after planting.

Then, water twice per month spring through fall. Always allow the soil to dry out between waterings.

No supplemental water is needed during the winter, provided there have been winter rains. And, as with all succulents, skip watering when freezing temperatures are expected.

Should You Fertilize?

There is no need to fertilize aloes growing in the ground. They get all they need from the surrounding desert soil. But if you grow one in a container, fertilize it lightly a few times a year when it’s actively growing.

Pruning

Cape aloe doesn’t need pruning, other than removing spent flower stalks.

You can remove old, dried leaves but you don’t have to. When left unpruned, they form a skirt, similar to palm trees. Many gardeners prefer this no-maintenance choice.

Plant Lover Facts

Cape aloe (Aloe ferox) also goes by the common names tree aloe, bitter aloe, tap aloe, and red aloe. It’s native to the rocky slopes, open scrublands, and grasslands of southern Africa.

Cape aloe has similar medicinal properties and uses to aloe vera and is important commercially. It’s sold as a supplement for treating constipation and arthritis, and is an ingredient in skin care products and shampoos.

The genus Aloe has over 500 species. When you see an aloe, you can know for sure it’s not native to the desert southwest, since all aloes are native to the eastern hemisphere.

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Author Bio

Deane Alban is the creator of Southwest Gardener. She is a science writer with a bachelor’s degree in botany from the University of South Florida. Gardening is her lifelong passion. She’s been gardening in Tucson for over 15 years.

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