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Aglaonema: The March 2023 Houseplant of the Month

Photo: Colin Laverdure.

When you think of the typical “green patch in the back of the room” type of plant, you might think of the Aglaonema (Aglaonema spp.). A classic of shopping malls and airports, the Aglaonema is rarely included in the “top 10 most beautiful houseplants” and is not very popular, but it is widespread and available everywhere, especially since it is included in all the “top 10 easiest houseplants” lists. Indeed, the modest Aglaonema, or “Chinese Evergreen”, tolerates harsh growing conditions and offers a pleasant foliage for the most austere places. You will see that its reputation as a “boring plant” is not at all deserved!

Origins

The Aglaonema is a member of the Araceae family and comes from the tropical and subtropical regions of Asia and New Guinea. Accustomed to hot and humid climates, it grows in the shade of more aggressive growing vegetation. It is thought that the silvery hue of many cultivars is intended to reflect the little light that eventually reaches it, in order to improve its photosynthesis. Aglaonema has been grown in Eastern countries as a houseplant for several centuries and spread to Western homes in the late 19th century. In Asian culture, it is known to bring good luck, like many plants.

There is a lot of confusion between Aglaonema and its cousin Dieffenbachia.

Image: Addisonia: colored illustrations and popular descriptions of plants, vol. 9, par le New York Botanical Garden, 1924.

Description

The aglaonema is an herbaceous perennial that grows on a medium thickness stem (sometimes thin in some newer cultivars), straight, with elliptical leaves that hide the stem during the first years of its life. Although it may resemble a trunk, the stem never covers itself with bark. In older cultivars, you can see the leaf scars, as well as some nascent buds from which new leaves could emerge if the plant were pruned (see details below, in the “Maintenance” section). Most plants remain modest in size, but some cultivars can reach a meter in height. As it approaches a certain height (and weight), the stem will eventually arch; in the wild, it will ultimately root into the ground.

Its inflorescences are reminiscent of those of other plants in the Araceae family, but without the color of anthuriums or the white delicacy of peace lilies. At the bottom, a bud is starting to open. Photo: Aniolek

Aglaonemas are usually composed of a single stem and do not form branches. It can happen that with a major pruning, two sleeping buds wake up and produce two stems, but generally only one stem replaces the one which was pruned. Aglaonemas eventually produce offshoots, i.e. “babies” that will emerge from the ground a few centimeters away, produce leaves and have their own root system.

Aglaonemas produce inflorescences both outside and inside our homes. They are mistaken for a leaf when they first appear, then become distinct and eventually look like a large whitish or green bud. The inflorescence is revealed at the end of a stem longer than the leaf stalk. Eventually, the spathe reveals the male (above) and female (below) organs. In some cultivars, the inflorescence barely opens. When grown indoors, Aglaonemas are unlikely to produce a berry followed by a viable seed.  


Varieties

Good luck with that! Like many houseplants that have been cultivated for some time, aglaonema is happily hybridized and every year new cultivars appear. As I have not yet founded the Society of Aglaonema Lovers (SAL?), there is no authority that regulates these new cultivars: so chaos reigns. Some cultivars have several names, or are so similar to others that it is difficult to distinguish them, and “2.0” formats appear, identical, but improving a certain aspect of the plant (reduced size, tolerance to cold, etc.). Even nurseries have a difficult time and often make identification mistakes, despite their best efforts.

The following list is by no means exhaustive, but rather presents various varieties that can occasionally be found in Canada.

From left to right: ‘Maria’, photo par David J. Stang; “Tigress”, par Krzysztof Ziarnek, Kenraiz; ‘Stripes’, par Dinkum.

Green-Leaved Aglaonemas

Green Aglaonemas often have a very good tolerance for low light. The leaves are variegated with various shades of green and the stems, usually broad, are also green.

We can find, for example, these varieties.

Silver-leaved Aglaonemas

De gauche à droite: ‘Silver Bay’, photo par Jerzy Opioa; ‘Silver Queen’, par Em?ke Dénes; ‘Cutlass’, par l’auteur; ‘Silverado’, par David J. Stang

In many cultivars, the leaves are variegated with a more or less silvery green, which is particularly shiny in good light. They generally tolerate limited light well.

Among the most common varieties:

Aglaonemas With Colored Leaves and Green Stems

From left to right: ‘Snow White’, photo by Mokkie; ‘Pink Dalmatian’ and, ‘Wishes’, by the author.

This brings us to the colorful cultivars, which are absolutely breathtaking! Here, the stems are fleshy and green, but the leaves are so stained with cream, pink and sometimes red or chartreuse that they look more colored than green. To keep the color, medium light is necessary.

There are many cultivars, for example:

Most white-stemmed Aglaonemas have white in the leaves. Left: ‘Snow Cap’, photo by Forest & Kim Starr; top, ‘Brilliant’, by David J. Stang; bottom, ‘White Rain’, by the author; right, unknown cultivar by Sigit Jati.

White-Stemmed Aglaonemas

There is a whole series of cultivars that are interesting not only for their foliage, but also for the stems that adopt shades of cream and white. These cultivars are rarer in Canada and are often identified by fancy names. Depending on the amount of white in the leaves, they prefer more or less light.

From left to right: ‘Siam Aurora’, photo by Mokkie; ‘Sparkling Sarah’, by Krzysztof Ziarnek, Kenraiz; ‘Golden Fluorite’, by the author; ‘Red Emerald’, by the author.

Pink-stemmed Aglaonemas

This last group is the most colorful, but it is also the one that needs the most light: minimally a medium light, and if possible, bright. The pink stems are the thinnest. Despite what the sellers say, the colored Aglaonemas are slightly more difficult to grow than others. However, they remain globally easy and rather tolerant plants.

Growing an Aglaonema

Some of the more expensive aglaonemas are so colorful you wonder how they photosynthesize! Photo by Mokkie.

Light

The light requirements depend on the cultivars, as mentioned above. I won’t give a lecture on photosynthesis, but let’s remember the following rule of thumb: the less green the plant, the more light it needs.

Aglaonemas have a reputation for tolerating the darkest corners, but that doesn’t mean they like them. Those with a lot of green will handle insufficient light better, greatly slowing their already slow growth to tolerate this suboptimal condition, but the colored versions will prefer to receive medium to bright light to develop beautiful colors. Direct sunlight is avoided as it can burn the leaves, especially when it is at its zenith.

Helpful Hint!

Occasionally, give your Aglaonema a quarter turn to balance its tendency to orient its leaves toward the sun, which is called phototropism.

Watering

The aglaonema has developed a certain tolerance to drought and is therefore very forgiving to people who forget them. Being very sensitive to root rot, it dreads overwatering. Thus, it is recommended to wait until the soil is almost dry before watering it again, especially when it is exposed to low light. Beware of soils that appear dry on the surface, but remain moist deep down!

Atmospheric Humidity

Although it comes from the humid jungle, the aglaonema tolerates the level of humidity usually found in houses without any problem. However, it does appreciate higher atmospheric humidity.

Reminder: Misting to raise humidity is a horticultural myth to be debunked.

Potting Soil

Aglaonemas are not too demanding in terms of potting soils and accepts most commercial potting soils for tropical plants that are easily accessible. However, if you are feeling generous, it can be interesting to add draining elements: wood chips, perlite, etc.

Repotting

Considering its propensity for root rot, Aglaonema prefers to be rather cramped in its pot, which reduces its chances of staying too long in waterlogged soil, asphyxiating the roots. Because it grows so slowly, repotting is not frequently necessary, unless the roots overflow from the pot, in which case a slightly larger pot is preferred.

For larger subjects, replacing the top inch of soil is quite acceptable.

Remember: no drainage layer!

Fertilizers

Since the plant does not grow very fast, it does not need much fertilization. In fact, Mr. Hodgson himself admits that he has not fertilized his aglaonema in 13 years. When fertilizing, give priority to a very diluted dose (for example, one eighth of the recommended dose) and only during the growing season. Since the aglaonema does not want to bother, it will be satisfied with the fertilizer you have.

Temperature

It is a tropical plant, so avoid temperatures below 13 °C, because the foliage will be damaged. However, you can take the plants out in summer when temperatures are mild. They will benefit from it, but do not expect a drastic transformation.

Although difficult to acquire, there is an aglaonema ‘Variegata’ for fans of albino plants, photo by David J. Stang.

Maintenance

Aglaonemas require slightly more maintenance than a plastic plant, which is almost nothing. In addition to watering, it is necessary to occasionally remove a leaf at the base (the oldest leaves turn yellow; they should only be removed when they no longer offer resistance.). Although it is not absolutely necessary, we often choose to remove the flowers, because they bring little attraction. It is preferable for the plant to concentrate on producing leaves. Like all other plants, the Aglaonema can have a tendency to collect dust: a simple wipe with a slightly damp cloth is all it requires to shine again.

Here’s an old aglaonema that could use a little pruning. Look at the long trunk bending over itself, photo by H. Zell

Pruning of the aglaonema is rarely necessary. After several years, it happens that the stem, stripped of leaves or crooked, does not look so elegant anymore. At this point, a rejuvenation cure can be beneficial (see the excellent article A Houseplant Makeover, which details what can be done with an old aglaonema.)

Propagation

There are several ways to multiply aglaonemas, as long as you are patient.

The simplest method is to wait until they make babies naturally. When these have several leaves and a proportional root system, you can take them by cutting the root that links them to the mother plant and make an individual plant.
Aglaonemas can also be cut, as long as a part of the trunk with some nodes is taken. The cutting can be put in water, where it will produce roots in a few weeks, sometimes a few months. With this technique, the cuttings suffer from the transfer from water to soil. It is wiser to put them directly in the ground. Aglaonemas being so slow to make their roots again that it is necessary to cover them with a dome or plastic bag to keep the humidity.

Helpful Hint!

I love Aglaonemas and I have a lot of them, but I have a terrible time with cuttings. I lose them either to drought or rot; it’s as if they refuse to make roots… My solution is to cut them in the summer. When the night-time temperatures are above 13°C, I take the plant I want to cut out and let it adapt to the light and humidity outside for a week or two. Then, I take the cutting and plant it in a pot of moist soil, which is left to the wind. At the beginning of autumn, it will have made small roots. They are then placed in their own personal greenhouses and gradually taken out. And that’s it!

Some aglaonemas make “dieffenbachian” sized leaves! Photo by Mokkie.

Problems

Toxicity

Like many Araceae, aglaonemas are toxic when ingested due to the presence of calcium oxalate in all its parts. They can also cause skin irritation in some people. Although we rarely hear of a case of serious poisoning from aglaonema, it is best to keep it out of the reach of young children and pets.

Red Aglaonema showing fleshy roots, varying from white to green, leaf petioles and the stem composed of various successive sections. The second stem on the left is a reject. Photo by Mokkie.

Buying Tips

There you go, the article has convinced you to buy an aglaonema! What should you look for to make sure the plant is healthy?

First, of course, the foliage should be visually pleasing, not too damaged by cold and transportation, and appear bright and firm. Inspect the underside of the leaves, the vein and near the stem, to avoid insects hiding there.

Then look at the number of stems: for a nice effect, we want several plants in the same pot (traditionally three), so try to find the plant that has several offshoots at the base or even an extra plant (a kind of clover with four Aglaonemas). Pull the stems slightly: they should be well rooted. The Aglaonema is dying slowly; the plant might be beautiful, but already on the downward slope.

If you can, look at the roots: they should be white or greenish. If the roots are browned, they have started to rot.

Another trivial piece of information: the Aglaonema has been included in the list of air-purifying plants of Nasa, purifying formaldehyde and benzene. To have a significant effect, I advise you to put 150 of them in a small closed room.


Available in a variety of cultivars for almost any taste, aglaonemas decorate darker areas and require minimal maintenance.

Photo: Picasa.
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