Houseplant of the month

Baby Sun Rose: The January 2024 Houseplant of the Month

Photo: Noric Couderc.

My Mesembryanthemum cordifolium is probably the plant that’s given me the least trouble, from maintenance to propagation. A wonderful discovery, 5/5, I’d recommend it to all my friends! Even though it’s a hassle to pronounce.

Origin of the Baby Sun Rose

Mesembryanthemum cordifolium is native to South Africa. It belongs to the Mesembryanthemum genus, which comprises 108 species in the Aizoaceae family. Another plant in this family that is occasionally grown is Lithops, the plant that pretends to be a stone.

Mesembryanthemum is also known as Aptenia cordifolia, one of four species in the genus Aptenia (also in the Aizoaceae), but its name has officially been Mesembryanthemum cordifolium since 2007. Which is a pity for me, because Aptenia is much easier to write…

It’s also known as Baby Sun Rose, Heartleaved Midday Flower or Heartleaf Iceplant. Many mesembryanthemums are called iceplant, because of their shiny appearance. Its other, less common and outdated scientific names are Litocarpus cordifolius, Ludolfia cordifolius and Tetracoilanthus cordifolius.

Although mesembryanthemum is often seen as an outdoor plant, a classic for sunny window boxes, it’s also a very easy indoor plant to grow. Photo by the author of a planter in downtown Montreal.

Description

Mesembryanthemums are small groundcovers with succulent leaves and stems. Older stems eventually become covered with bark, but this is a form rarely seen, as it is not a particularly long-lived plant. When the plants, initially lazily erect, reach a height of around 10 centimetres, they begin to droop into a drooping form. Like other ground covers, mesembryanthemum seeks to root where it touches the ground, multiplying easily in this way. Stems can grow up to 90 centimetres long, but are often broken off long before that.

The leaves of the Baby Sun Rose, contrary to what its name suggests (cordifolium means “heart-shaped”, hence its vernacular name), are rather ovoid or slightly heart-shaped. Even in older species, leaves rarely exceed three centimetres. They grow opposite one another along the stem, with a rather short internode. At the end of the stem, a solitary pink, red or purple flower appears and lives there for a few days. It opens in sunlight and closes at night or on grey days.

What appear to be petals are actually modified stamens, staminodes, the normally yellow part inside flowers on which pollen is found. Photo by JJ Harrison.

Varieties

The natural version, with its green leaves and magenta flowers, is almost never found commercially, in favor of more attractive cultivars.

Mesembryanthemum cordifolium. Photo: Andrew Butko.

‘Red Apple’

It’s the result of hybridization between M. cordifolium and M. haeckelianum, named M. cordifolium ‘Red Apple’, which we see sold as an ornamental plant. It offers more vigorous growth, a denser habit with glossy green leaves and red flowers.

Mesembryanthemum ‘Red Apple’. NNote its compact habit and the bright red flowers that emerge from it. Photo: Kenpei.

While ‘Red Apple’ is a horticultural hybrid, ‘Mescliba’ was a spontaneous mutation, originating on ‘Red Apple’. A spontaneous mutation is an offshoot or branch that displays characteristics different from the parent plant, such as leaves with a spot of color or an altered shape. For more information on mutations, please read the article When Plants Mutate.

‘Mezoo™ Trailing Red’

Not all mutations give rise to new plants, but in the case of M. × ‘Mesblica’, it was stable enough for the plant to be multiplied on a large scale. This new cultivar can be found under its commercial name, ‘Mezoo™ Trailing Red’. It retains the attractive characteristics of ‘Red Apple’ (dense habit, vigor, red flowers), which it enhances with green foliage generously variegated with white borders.

Mesembryanthemum × ‘Mesblica’. In the foreground, you can see the modified leaves surrounding the flower bud, ready to bloom on the next sunny day. Note the white variegation around each leaf. Photo: Salicyna.

As if the confusion between Mesembryanthemum cordifolium and Aptenia cordifolia wasn’t enough, Mesembryanthemum × ‘Mesblica’ can also be found under the little name of Dorotheanthus bellidiformis ‘Mezoo™ Trailing Red’. For full information, see the article Help Me Put a Name on This Plant.

Other very similar plants with crimson, white or cream flowers exist and confuse taxonomists – are they Mesembryanthemum or close cousins, like Delosperma? Whatever the case, they can be treated according to the following advice.

Growing Tips

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Light

The Baby Sun Rose likes full sun, especially indoors. It tolerates bright light, but quickly fades in average light.

Watering

As a succulent plant with thick stems, mesembryanthemums offer good tolerance for forgetful gardeners; however, during the growing season, i.e. in bright light, they will grow best with frequent watering. Leave to dry out during the less sunny months, when the plant rests and is more susceptible to rot.

Atmospheric Humidity

Mesembryanthemum comes from a desert climate. Humidity increases the risk of rotting.

Potting Soil, Potting Soil and Fertilizer

This plant thrives in poor, desert soils; it prefers poor potting soils, which dry out quickly, and does not appreciate fertilizer. Since commercial potting soils are often laced with fertilizer, it can be useful to add sand, reducing the amount of rich potting soil needed and increasing drainage as a bonus. It grows very well in cramped conditions.

M. cordifolium is salt-resistant. On the rare occasions when I repot it, I use the old topsoil from the other plants. Photo by Mokkie.

Temperature

Avoid subjecting the Baby Sun Rose to frosts, which would be fatal. Below 10°C (50°F), the plant enters a resting period. It prefers cooler temperatures in winter.

Beware of outdoor use of mesembryanthemum: it has become naturalized in the southern United States and Mexico, in Australia and in the Mediterranean, which can unbalance an ecosystem. Photo by Frank Vincentz.

Maintenance

M. cordifolium is an easy-care plant, but requires a little effort to make it look even better.

Like other groundcovers, mesembryanthemum is not necessarily the longest-lived plant. Basal leaves tend to dry out, leaving bare stems that hang sadly. Left to its own devices, it can also produce spaced stems, especially in the original species.

To give it a full appearance, simply prune and awaken the secondary buds. Baby Sun Rose branches easily. The plant can easily be cuttings during pruning.

Every year, severe pruning or complete cuttings will renew the plant.

J’avoue qu’avec les années, le mesembryanthemum devient légèrement défraîchi: cette potée gagnerait à être refaite à l’aide de boutures. Photo par Semnoz.

Multiplication

Nothing could be simpler: just remove a stem bearing six or eight pairs of leaves. After removing the lowest leaves to reveal the nodes, from which the roots will emerge, you can plant directly in potting soil. Unlike many other plants, potting soil doesn’t need to be watered heavily or placed in a greenhouse: in fact, dry (but not desert) soil is preferable, and cuttings in water should be avoided. Place the pot in a sunny spot.

If all goes well, in two or three weeks’ time, when you gently pull on the stems, they should offer some resistance, a sign that the roots have begun to develop. You can then start watering sparingly and gradually treat the plant like an adult.

Seeds can also be harvested and planted. Photo: par Boronian.

Problems

There are no insect or disease problems, apart from rotting in excessively humid conditions. If the plant lacks light, it will be pale and etiolated.

Toxicity

This plant is not toxic. In fact, it’s edible and could be used like spinach! But beware of pesticides from nurseries and fertilizers from commercial potting soils. Besides, hybrids weren’t designed for their taste, so it’s probably best to avoid them.

Conclusion

So yes, the name is long and I enjoyed the abbreviation M. cordifolium whenever I could while writing this article, but apart from that, it’s still an excellent plant that doesn’t cause any problems, perfect for peace of mind!

Photo: JJ Harrison.

Colin Laverdure has no qualifications other than his last name (Laverdure is French for "the greenery") and a slightly excessive passion for plants of all kinds, but particularly for houseplants. When he's not watering his personal collection, he's interested in writing fiction or singing with his choir.

4 comments on “Baby Sun Rose: The January 2024 Houseplant of the Month

  1. Delighted to see this! We ran into the “Mezoo” variety a couple of years ago and have been growing it in patio boxes, then overwintering a few small cuttings to replant for the following summer. It’s a terrific plant!

  2. ‘Mezoo’ works great as an edging for succulent containers. I have some around the edge of a variegated Agave americana. It’s a stunning combo. It overwinters most years in my garage with an average temperature of 5C as long as it’s kept dry and not too humid.

  3. Ferne Dalton

    Very happy to receive such detailed info on this interesting plant. Hoping to get mine to flower again this coming summer. Thank you.

  4. I absolutely adore this plant! Easy, peasy and always looks good. It was a nameless variety in a summer arrangement I had purchased, then potted up individually to overwinter so thank you SO MUCH for the excellent information. Definitely recommend as well.

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