One of many interesting succulent plants, the Haworthia cooperi, or Cooper’s Aloe has a compact habit, and its fleshy leaves almost look like a window into the plant.
It’s the perfect choice for an indoor succulent garden, as it doesn’t need much attention in order for it to thrive.
At a Glance: Haworthia cooperi Plant Facts
One of the most varied types in the Haworthia genus, all Haworthia cooperi plants feature transparent ‘windows’ or fenestrations, near the tips of the leaves, making for a fascinating display. This is why it’s also called the cathedral window haworthia.
In some cultivars, nearly all of the leaves are transparent.
Most of the plant sits below the level of the soil, so it’s these lovely leaves that steal the show. They appear in small rosettes, usually either in a bluish green or a more lime green.
The windows of the leaves help curb some of the harshest rays of the sun, helping the plant to weather the difficult conditions.
These plants, also known as Cooper’s aloe, come from the Asphodelaceae plant family, and are only native to the Eastern Cape of South Africa.
It can be confusing to know what is a Haworthia cooperi, as it shares several names with other plants, such as the cushion aloe and Cooper’s aloe, though it’s not related to the aloe plant family, it only resembles it.
Like many succulent plants, Haworthia cooperi is grown for its ornamental value with its unusual leaves, but it also produces flowers in spring and summer, usually a tiny show of white blooms.
How to Grow Haworthia cooperi
If you’re new to growing succulent plants, the Cooper’s aloe is an excellent place to start, as it’s one of the least-demanding species, as well as being self-propagating and inexpensive.
Of course, this is only true when you provide it with the right conditions, which are covered below.
The Right Light for Haworthia cooperi
As Haworthia cooperi are succulent plants, you might assume that they want as much light as physically possible, for as long as possible. Unfortunately, you’d be wrong.
While they can survive in full sun, partial shade is best, as full sun can tint the leaves an odd color, possibly red, yellow, or white.
You can also see their reluctance if you look at the leaves – in some varieties, only the very tips of the leaves poke through the surface of the soil.
You can also find them growing under the shelter of much larger plants in the wild.
Because they like partial shade or indirect light, this makes them perfect as houseplants, as not all of us have south-facing window sills!
They will also grow well in full morning light, which doesn’t get as fierce as the sun’s rays in the afternoon.
Watering Your Haworthia cooperi
In warmer conditions, Haworthia cooperi requires regular watering, as soon as the soil dries out, but not before!
This may mean that you’ll have to water it weekly, but in winter, you can drastically reduce this to once a month or less, only to stop the leaves from drying out.
Haworthia cooperi has adapted to go without water for long periods of time, which means that the only thing that will happen if you forget is that the leaves will shrivel slightly.
It’s best to underwater your Haworthia cooperi rather than risk overwatering it, as these plants are vulnerable to root rot.
If you leave moisture sitting on the leaves – or mist the leaves, you’ll find that they will rot.
Ideal Temperature and Humidity for Haworthia cooperi
These succulents also make good houseplants because they like atmospheres with very dry air, which is often created indoors.
They aren’t cold tolerant, but that won’t matter indoors, as indoor temperatures rarely get low enough to harm these plants.
It is recommended that as well as scaling back the watering, move your Haworthia cooperi to a colder position than normal, as this will help it go into a dormancy period.
The Best Soil for Haworthia cooperi
Like with all plants, it’s best to mimic their native growing conditions, and this extends to the soil. The soil you choose needs to be extremely well-draining, preferably sandy and rocky in texture.
You can either buy a ready-made succulent potting soil, which is perfect for Haworthia cooperi, or mix your own by using one part potting soil and one part sand.
For added protection, you can also cover the surface of the soil in horticultural grit to stop the leaves from rotting on the surface of the soil, though this makes gauging the moisture of the soil a little more difficult.
You can bypass this by putting a finger through the drainage hole in order to judge the moisture level in the soil.
Haworthia cooperi and Fertilizer
You don’t need to fertilize a Haworthia cooperi. Like most succulent plants, feeding them can do more harm than good, so it’s best not to pick up that plant feed.
How to Propagate a Haworthia cooperi
The best way to propagate a Haworthia cooperi is using the offsets the plant produces. Wait until the offset has rooted well, and then separate it from the parent plant and repot.
You can also grow these plants from seed, and while it’s not as quick, it’s fairly easy.
Haworthia Cooperi Varieties You Should Consider Growing
Haworthia cooperi ‘Black Muscle’
One of the most unusual cultivars you can get, ‘Black Muscle’ lives up to its name, producing very dark foliage in a fleshy and compact form.
The leaves are very pointed, and usually come in a slate-blue or a dark purple.
It’s a rare cultivar, and if you place it in weak sunlight, it will glow like a beacon.
Haworthia cooperi ‘Leightonii’
One of the larger types of Haworthia cooperi, ‘Leightonii’ has an upright habit, still forming yellowish green rosettes.
It is a vigorous plant which will produce many offsets, and these leaves can become tinged with red in full sun.
Haworthia cooperi ‘Picturata’
Another succulent with a vigorous growing habit, ‘Picturata’ can vary color and form within the same rosette, featuring round or squat leaves, usually a pale green with a tinge of yellow.
It can also produce 20 white flowers per flower stalk in spring and summer.
Haworthia cooperi ‘Pilifera’
Probably the most common variety after Haworthia cooperi cooperi, ‘Pilifera’ has compact leaves which are usually a grayish green, with fairly large fenestrations.
It can grow up to 30cm in diameter if given the right conditions.
Haworthia cooperi ‘Tenera’
Haworthia cooperi ‘Tenera’ produces long pointed leaves in a star formation. These leaves are also not as transparent as other varieties, making for an unusual look.
It’s much slower in its growth habit than other varieties, making it perfect for a pot that you don’t want it to outgrow anytime soon.
Haworthia cooperi ‘Venusta’
One of the most attractive varieties, Haworthia cooperi ‘Venusta’ features compact triangular leaves, usually covered in hair and toothed around the edges. The individual leaves can get to a maximum of 2 inches long.
Haworthia cooperi ‘White Variegata’
This Haworthia cooperi is very nearly white all over, and forms in a striking star-shape, each leaf ending in a very fine point. It’s one of the palest varieties available, and among the most unusual.