Arrowleaves, also called alocasias, are challenging to keep in indoor culture. Therefore, caring for them as optimally as possible is critical.
Find out how in the following care guide.
Origin of the arrowleaf
The arrowleaf or Alocasia is listed under the botanical names Alocasia lowii or Alocasia longiloba, although the former is more commonly used.
It is a member of the arum family (Araceae).
Initially, the tropical plant came from the Malayan island of Borneo.
One of the best-known Alocasia species is the Alocasia zebrina.
Appearance and Characteristics
Alocasias are beautiful foliage ornamental plants that can grow about 50 centimeters high.
They form tuberous rhizomes (shoot axis systems growing underground or close to the ground, called “earth shoots”) and loose clumps (plant growth habit in which many plant shoots are close together).
Arrowleaf leaves are long-stalked and grow immediately above the ground or at the base of a plant shoot.
They are oval and, as the name implies, arrow-shaped. They also have a green and white pattern.
The leaf blade, i.e., the flat part of the leaf above the style, is shiny dark green and shows a white pattern along the leaf veins. The underside of the leaf, on the other hand, is purple to violet.
The leaves can grow 8 to 12 inches long and over 4 inches wide..
The flower
The flower of Alocasia lowii is relatively inconspicuous in contrast to the houseplant’s leaves.
It consists of a sepal and a cob growing out of it. In most varieties of arrowleaf, the sepal is light green, and the spadix is yellowish.
The inflorescences are often cut off directly so they do not take too much strength from the Alocasia.
The fruit
From the flower of the arrowleaf grow many red, small berries, which are highly poisonous.
Caution. Gloves should always be worn when cutting off the inflorescence to prevent the milky sap from getting on your skin.
The optimal location for the arrow leaf
The arrow leaf prefers to stand in partial shade and shady places in the room.
It gets along with typical room temperatures all year round. However, since the Alocasia longiloba is tropical, it does not tolerate cool drafts. In addition, temperatures should never drop below 64 °F, for example, even in winter.
Overwintering Alocasia lowii
In addition to temperatures, heating air also challenges Alocasia in winter.
You should ensure that the humidity remains sufficiently high for the arrowleaf. That is provided, for example, by a humidifier or other methods.
In addition, Alocasia longiloba should not be fertilized in winter and should be watered more sparingly than during the rest of the year. However, even then, the substrate should only dry out partially.
Watering Alocasia longiloba
During the rest of the year, the soil of the Alocasia should always be kept evenly moist. However, the soil may dry superficially between waterings.
Waterlogging should not occur when watering, as the plant does not tolerate this well. Accordingly, you should shake off the excess water immediately.
Ideally, only room-warm, low-lime water should be used when watering.
Fertilize Alocasia lowii
The arrowleaf is sufficiently supplied with nutrients by weakly dosed fertilizer applications every two weeks.
You can use No products found.. It would be best if you halved the specified dose for the Alocasia.
However, you should follow this rhythm only from April to September. In the remaining months, the houseplant should not receive fertilizer.
The perfect substrate of the arrowleaf.
Regarding the substrate, the arrowleaf is demanding. Suitable is a humus-rich mixture of expanded clay, sand, and peat moss (Sphagnum).
The first two proportions of the mixture can ensure permeability and good drainage in the pot.
Repot Alocasia longiloba
When the pot of the Alocasia is no longer sufficient for its roots or its soil is no longer fresh, it is time to repot.
Usually, this is done about every two years. However, you should repot the plant only in early spring.
That involves detaching the plant from its old substrate as usual and transferring it to a new, larger container with fresh soil.
Caution. Since Alocasias, like all arum plants, is poisonous, always wear gloves when repotting (cutting, propagating, or caring for Alocasia) to avoid possible skin irritation.
Cutting the arrow leaf
Generally, cutting the leaves themselves is optional.
However, if your Alocasia is getting too big for you, you can cut the shoots back to two-thirds with clean (garden) scissors or a clean knife.
That is best done in the spring, just like repotting. Likewise, you should remove dead leaves.
Tip: applying charcoal powder* to the cut afterward can prevent pathogens from entering the plant.
Propagating Alocasia lowii
In general, mainly only larger or older alocasias should be propagated.
The root system of younger arrow leaves still needs to be sufficiently developed, and they cannot yet produce seeds for propagation.
Propagation by root division
Arrowleaf can be propagated by dividing its rhizomes into several pieces with a clean, sharp knife.
Since you must detach the plant from its soil beforehand, it is convenient to cut off the offshoots directly when repotting, for example.
After the offshoots have dried, you can plant them on a suitable substrate.
Good conditions for the Alocasia lowii, such as warm temperatures and high humidity, are crucial for the success of the process.
Propagation by sowing
The second variant is based on the seeds that the arrow leaf itself produces.
In general, you can carry out this process all year round. However, the high is particularly suitable for summer.
It is best to plant the seeds promptly, that is, within about a month after they are obtained.
Before that, the seeds should be poured with hot water and swell for about two days.
Afterward, you can plant them about one centimeter deep in a suitable substrate. The right conditions (high temperature and humidity) will help the plantlets to grow.
They should be watered regularly with low-lime water and sprayed daily during the growth phase.
After about a month, you can separate the tiny plants. Now they are also cared for like adult Alocasias.
(Image: © eddows – stock.adobe.com)
Diseases, pests, and care mistakes of the arrow leaf.
Arrowleaf can be affected not only by various pests but also care mistakes giving it a hard time.
Especially in winter, cool temperatures usually result in root rot or pest infestations.
It is crucial to identify and counteract these problems through regular inspections quickly. Find out how to do this in the following segment!
Diseases and pests
Infestation by whiteflies
When the arrowleaf is infested with whitefly, the sticky honeydew on the leaves is the first thing you notice. The leaves of the Alocasia also get spots and turn yellow over time.
In addition, the pests can be identified by the fact that they fly around when the plant is touched.
For control, frequent airing is suitable, and spiders or ichneumon wasps are natural predators. Yellow boards*, which are attached to the houseplant, can also help.
Infestation by spider mites
In case of heavy infestation, spider mites can be recognized by webs spread on the plant. The little animals are only up to half a millimeter in size and red.
They destroy the Alocasia by sucking on its leaf undersides. The leaves of the plant have small bright spots that can quickly become more prominent brown spots.
You can control the pests by showering the plant or rubbing the leaves with a dishwashing liquid solution. Also, a decoction of nettle leaves, onions, or garlic can help.
Another option for control would be gall midges or ichneumon wasps, which act as natural predators.
Infestation by aphids
Aphids settle on houseplants to suck out their sap, thus damaging them. As a result, their leaves wilt, turn yellow and fall off.
To fight them, you can wipe the leaves of the Alocasia with a detergent solution or shower the plant.
It also can be used for nettle or onion sap or natural predators such as ladybugs, spiders, or gall midges.
Infestation by mealybugs and scale insects
You can identify woolly aphids as small gray to white “tufts” of wool in leaf axils or on buds.
On the other hand, scale insects can be identified by dark brown thickenings one to three millimeters in size on twigs, leaf veins, or on buds.
For pest control, wiping with dishwashing liquid or alcohol helps. In addition, you can also scrape off the little insects carefully.
Aids for pest control
An application is also recommended for all pests, especially in case of heavy infestation.
However, the means should be suitable for the respective type of pest. You can usually find that on the packaging.
Care Mistakes
Alocasia lowii gets yellow leaves
A common consequence of care errors can be dull, yellowing leaves. These causes can be behind it, and this is how you can counteract them:
- Waterlogging: the plant should be planted in a new substrate as soon as possible
- Dryness: If the arrow leaf is too dry, you should urgently ensure a higher humidity.
- Cold: A change of location can help
Likewise, it can also happen that the leaf is old and dies naturally. In this case, there is no faulty care.
I will answer your questions!
Is the arrowleaf poisonous?
Like all aroids, the arrow leaf belongs to poisonous plants (for humans and animals).
Certainly, Alocasia is not highly poisonous, but still, you should be careful when caring for it and always wear gloves.
The milky sap, which is contained in all parts of Alocasia longiloba, contains toxins that can cause inflammatory reactions on the skin.
Caution. The milky sap should never be ingested, as stomach and intestinal problems or, worst case, cramps, and circulatory failure may follow.
The berries in the plant’s flowers are also considered very toxic, so you should permanently remove the inflorescences. Especially if you have children or pets, the arrow leaf may thus not be the best choice.
Is Alocasia lowii challenging to care for?
Alocasia is a rather demanding plant, so plant novices should not choose it.
However, following the tips in this care guide, keeping arrowleaf should be relatively trouble-free.
Why do the tips/edges of the arrowleaf turn yellow or brown?
In this case, the Alocasia is probably standing too dry. The Alocasia lowii should be sprayed or moved more frequently to solve the problem.
Take advantage of this!
Sources
Wikipedia 1
Wikipedia 2
Wikipedia 3
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