Alocasias, tropical beauties with big leaves
A statement plant with large leaves
Alocasia, also known as elephant ear, is a genus of plants in the arum family, the “aroids” (Araceae). They are medium-sized to massive herbaceous plants with a thick underground rhizome and huge leaves. Alocasia has more than 70 cultivars, from robust to smaller species, and in the wild they grow exclusively in tropical and subtropical regions from India to southern China, Indochina and Southeast Asia, all the way to Australia and Oceania. They most often grow in the understory of humid forests and rainforests.
Alocasias are evergreen plants that, in our climate, are grown exclusively as houseplants; they can also be used in greenhouses or outdoor atriums sheltered from wind and scorching sun. When young, the plant grows upright from an underground rhizome that thickens over time; once it reaches a certain size, the plant may start to lean and bend under its own weight. If you want it to stay straight, it is recommended to give it bright indirect light from all sides, so the plant does not tend to lean toward the light.
Alocasias are very interesting for their size, shape and colors. For lovers of large leaves, it is the right houseplant, holding its own against other large-leaved houseplants such as caladiums, monsteras, ficus plants or birds of paradise. Let’s take a look at what you should know about it before you bring one home.
Photo: Alocasia Portodora also grows to a large size
How to care for it
Alocasias tend to be plants for more experienced growers, for several reasons. This is a plant that truly loves humidity, so it is less suited to dry homes that lack even natural humidity. At the same time, you need to be careful with watering, repotting and choosing the right spot. On the other hand, if you follow a few tips, it will reward you with beautiful leaves and vigorous growth, so even a beginner can manage its care.
Light conditions
It does not need much light and is also happy in a moderately shady corner of your home, away from the window. Alocasias like to stretch toward the light, so it is not unusual for yours to grow sideways rather than up; simply turn the plant once a week. The best placement is, of course, diffused light from all sides or from above. In summer, do not expose it to direct sun, or the leaves will scorch. Otherwise, it tolerates full light and east-, north- or west-facing windows well. In shadier spots, it does not color up as well, the leaves may start to turn yellow over time, and growth slows down. Naturally, this also affects the size of the leaves: in a shady spot, your plant will tend to produce smaller leaves.
Photo: Alocasia Frydek
Temperature and humidity
Alocasias love warmth and humidity. Avoid cold drafts, especially in the winter months, and spots where the plant would be exposed to drafts for long periods. In winter, the temperature should not drop below 18°C; ideally, we recommend a normal room temperature of around 24°C.
Alocasias are most demanding when it comes to humidity. This tends to be the stumbling block when growing them in dry homes, especially in winter, when the heating is on as well. You can help them by regularly misting them with soft water, that is, boiled water or rainwater. Do not use water straight from the tap, as unsightly brown spots could start forming on the leaves. From time to time, you can also wipe the leaves with a damp cloth, but be careful. Check which type of Alocasia you have: for example, Alocasia Frydek or Alocasia Black Velvet have velvety leaves (with fine hairs), and with these plants you would probably ruin the leaf by wiping it with a damp cloth. If you are a high-tech grower, a humidifier in the room will do your Alocasia a lot of good.
Photo: Alocasia Dragon Scale, whose texture resembles dragon skin.
How to water Alocasias
Alocasias are plants that love high air humidity and warmth, but when it comes to watering, they do not like waterlogged soil. Chronic overwaterers will only be repaid with a dead plant. Of course, you need to take into account the size of the planter, its material and location, the humidity in your home and, last but not least, the type of potting mix the plant is growing in. Nevertheless, an Alocasia needs a constantly moist potting mix that is never waterlogged, and it must not stand in water. It is recommended to water more often but in smaller amounts, using room-temperature water, and to check the moisture of the potting mix with your finger.
The potting mix is in the right condition when its bottom layer is moist and its top layer is dry. If the soil is waterlogged, the roots and leaves start to rot, and whole leaves very quickly turn yellow and dry out.
Hydroponics, yes or no?
Definitely yes. Like all other plants of the “aroid” group, Alocasias grow very well in hydroponics or semi-hydro. However, if you decide to convert a plant that you already have at home in potting mix to hydroponics, be careful. Switching from potting mix to water tends to be fatal for many plants and takes time. The plant may even die. For better results, it is recommended to grow young plants this way.
A tip for hydroponic growing. If you decide to move your Alocasia from ordinary potting mix to hydro, in my experience even a larger Alocasia will survive it without much harm; what matters, though, is cleaning the roots very thoroughly of all remaining potting mix, rinsing them well under the shower and leaving them submerged in clean water for several weeks so the plant can acclimatize and form “water roots”. You will probably find that the large outer leaves drop off: this is normal, so do not worry; your Alocasia will grow new ones. Pull them off completely, right at the base of the plant, so that no part of the leaf remains, because it would rot in the water and cause mold.
- Martin
Suitable potting mix
The potting mix should be airy and light, and slightly acidic. It is recommended, for example, to mix peat with ordinary potting mix, combine it with pine bark or coconut chips and add a suitable amount of perlite for overall aeration. Make a drainage layer of expanded clay (LECA) at the bottom of the planter, which will help drain excess water and let the roots at the bottom breathe better. In our online store, you can also buy a ready-mixed aroid potting mix, which suits Alocasias too. If you would rather keep things simple with the potting mix, your Alocasia will also do well in ordinary potting mix for houseplants, but keep in mind that they do not like being waterlogged, so mix in at least some perlite.
Photo: Alocasia zebrina shows off striped stems resembling a zebra.
Repotting and propagation
You do not need to repot the plant often. For younger plants, it is a good idea to do it once a year, around March, as spring arrives, and for older plants about once every 2 to 3 years. Decide based on the condition of the potting mix and the root system. If the roots seem to be poking out in all directions, it is time to repot.
Alocasias are harder to propagate. The most common method is dividing the clump, provided your plant produces one. Alocasias only put out new offshoots, or “corms”, in good conditions and once they reach a certain size. If this happens, carefully cut the offshoot off together with its root, and you have a second plant. With corms, simply remove them carefully from the potting mix, and you can let them grow in a closed propagator.
Flowering
Like other plants of this kind, they have spathe flowers, which are only very rarely seen in our climate.
Diseases and pests
Like other plants, Alocasias can suffer from pests. This most often happens in a dry environment, when the plant is more vulnerable. The most common pests are spider mites, fungus gnats in the potting mix, or other parasites. With long exposure to sun and drafts, the leaves suffer, developing brown or dry spots that cause the whole leaf to drop. In that case, do not be afraid to cut off the whole leaf; your Alocasia will soon put out a new leaf, and it also tends to sprout well from its rhizomes.
Caution: it is toxic
Alocasia is a toxic houseplant, so watch out for small children and pets. Although it is used in herbal remedies in Chinese medicine, at home it is better to be careful, even when repotting. Contact with the sap that oozes from the roots or leaves when they are damaged can cause an unpleasant skin rash.
The best-known Alocasia species
The most common Alocasia species include Alocasia Polly, with its very striking dark leaves, firm texture and white veins. It is the one you are most likely to find at a florist. Another very common species is Alocasia Wentii, with darker green leaves and purple undersides; it reaches an admirable size and grows fairly fast. Other well-known species include Alocasia Portodora and Alocasia macrorrhiza Stingray
Among Alocasias, you will also find interesting species with unusually narrow leaves, such as Alocasia Longiloba or the attractive Alocasia Lauterbachiana. Also worth mentioning is a very unusual collector’s hybrid, Alocasia Brancifolia Pink Passion, which looks strikingly like Philodendron Xanadu and Alocasia Zebrina. This plant is very special, because it came onto the market fairly recently and you will not find it anywhere in the wild. Alocasia Dragon Scale can also make quite an impression, as its coloring and texture resemble a real dragon.
Popular, fairly expensive plants classed as rare species include Alocasia Melo, which has very stiff leaves with a grayish tone and a striking texture; some might almost think they are artificial. Alocasia Frydek has a fresh green color, velvety leaves and white veins. Its younger sister, Alocasia Frydek Variegata, which counts as a true rarity, is considerably more interesting, but unfortunately very hard to find.
Author: Martin Seidl