Alocasia Longiloba (A. Lowii)

Alocasia longiloba. Copyright: Kallus.com

Contents

1. Top Tips
2. Location, Water, Humidity & Fertilisation
3. Common Issues
4. Origins, Temperature, Propagation, Repotting & Toxicity.

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Top Tips & Info

• Care Difficulty - Moderate
• Bright indirect light is best, avoiding exposure to the summer sun. An hour or two of winter sunlight is highly beneficial, though, as long as you keep an eye out for potential droughts. Overhead lighting is key for this species, as locations too far from the window may cause wobbly or slanted growth.
• Keep the soil evenly moist, allowing the top third to dry out in between waters. Avoid water-logging or extended periods of soggy-soil.
• Mist the foliage or introduce a humidity tray whilst the heaters are operating.
• Fertilise using a 'Houseplant' labelled feed every four waters in the spring and summer, reducing this to every six in the colder months.
• Keep an eye out for Spider Mites that'll form webs on the under-leaves of the plant.
• Especially if its kept in a dark location, wash or dust the foliage monthly, to increase the light-capturing efficiency.
• Repot every two or three years, using 'Houseplant' labelled soil or a general purpose compost with some perlite. Introduce some grit for larger specimens, to strengthen their root system.

Location & Light - 🔸🔸

Although bright, indirect sun is ideal, throw in some morning or evening sun if possible. If it's situated in a shady location, dust the leaves from time to time to improve light-capturing efficiency. Never allow your plant to sit in strong sunlight for extended periods, as too much light will result in a pale, washed-out appearance with possible brown patches forming on the leaves.

Most rooms in the house will easily accommodate your Alocasia longiloba, as long as there's a sufficient amount of light and space to grow. If the plant is situated in a darker location, be sure to wash the leaves monthly to improve its light-capturing efficiency and overall appearance. Do not situate an Alocasia in a setting that's prone to extreme heats or direct sunlight, for example a south-facing conservatory, or within four metres of an operating radiator.

Water - 🔸🔸

Allow third of the soil to dry out in between irrigations, while reducing this further in the autumn and winter months. For those grown in brighter locations, only allow a third of the soil dry out to minimise the chances of dehydration. Under-watering symptoms include stunted growth, brown leaf edges and yellowing leaves. Over-watering symptoms include a collapsed stem, yellowing leaves and plant death. If you feel over-watering is to blame, remove the affected leaves, roots and soil and replace with a fresh batch of houseplant compost. Click on this link for more info about addressing root rot.

Humidity - 🔸🔸🔸

This species originates from South-East Asia, meaning high humidity is mandatory for quality growth. Mist both sides of the leaves once a week in summer and twice in winter; browning leaf-tips are a big sign that the surrounding air moisture is too low. A quick hose down once a month will hydrate the leaves, eliminate dust particles and help reduce numbers of pests, most notably Spider Mites.

Fertilisation - 🔸🔸

Feed every four waters during the growing period and every six in the autumn and winter, using a 'Houseplant' labelled fertiliser. Never apply a 'Ready to Use’ product into the soil without a pre-water first, as it may burn the roots and lead to yellowed leaves.

Common Issues with Alocasia Longiloba

An array of simultaneous cultivation issues will increase the chance of developing yellowed leaf-sections with browned halos - see image below for visual reference. Firstly, the location may be too dark, with its compost staying too saturated in-between waters; if mould is growing across the soil, this is usually a bad sign. Further, you're potentially using too cold water or tap water that hasn't been allowed to sit for 24hrs. The final culprit might be lack of fertilisation, with regular feeds being paramount for long-lasting, healthy leaves. If the specimen hasn't been nourished in over two months, it'll begin to show signs of nutrient deficiencies seen in this article.
If this common problem has occurred with your specimen, remove the affected leaves (not areas) and improve the growing conditions considerably. Fertilise regularly with lukewarm water and be sure to allow the top third to dry out in between hydrations.

Regular irrigations are key. Periods of droughts will quickly slip the specimen back into its dormancy period, causing stunted growth and a bewildered plant owner. If it hasn't repotted in a while, there may be too many roots and not enough soil to retain moisture, thus leaving the soil to dry out quicker. Click on this link to learn more about a transplant.

Pests could arise at any time, with infestations starting from the original nursery or via contamination in your home. Spider Mites and Mealybugs tend to be the usual inhabitants, with the first being minute and almost transparent, roaming the leaves in search of chlorophyll and a site to hide its eggs. The latter, however, will stand out much more, with white cottony webs developing across the foliage and stems. Thoroughly check the plant's cubbyholes before giving it the all-clear, or click on the appropriate links to learn more about eradicating these issues.

Alocasia can be riddled with pests due to its thin, broad leaves. In the image above, there's a third point of interest to look at - mineral/calcium deposits. This is a natural part of an Alocasia leaf's lifecycle, so don't worry about removing them!

Yellowing lower leaves (closest to soil) are a clear sign of over-watering, usually caused by too little light. Although Alocasia longiloba can do well in darker locations, the frequency of irrigations must be reduced to counteract the chance of root rot. People don't realise that a plant's root system needs access to oxygen too; when soil is watered, the air will travel upwards and out of the potting mix. A lack of accessible oxygen for the roots will cause them to subsequently breakdown over the oncoming days. Click on this link to learn more about root rot and how to address it, and always feel the pot's weight for confirmation (heaviness = good soil moisture, & vice versa).

Too low humidity can cause browning leaf tips with yellow halos. Although this won't kill your specimen, you may want to increase the local moisture to prevent the new growth from adopting these symptoms. Mist or rinse the foliage from time to time and create a humidity tray whilst the heaters are active to create a stable environment for your specimen.

Dust the leaves regularly. Although this isn't too much of an issue, a build-up of dust particles can clog up the plant's pores, causing lowered light capturing-efficiency. Wipe the topsides of the leaves down once a month to keep levels down and improve growing conditions.

If your Alocasia begins to wilt, it could be the product of one or many issues, ranging from the environment to your care habits. If the specimen is located in too low light, it may lead to plant-confusion when the window is several metres away. As mentioned in 'Location & Light', most Alocasia will require overhead lighting to complement its growth habit, with anything else causing either wilting or slanted growth. Secondly, irregular watering habits could cause root dehydration, which will eventually lead to wilting. Prolonged droughts will result in a lack of hydration in the upper part of the plant, with root rot doing the same - albeit it with overly soggy compost. Finally, environment shock could be the final culprit of your wilting Alocasia. If the specimen has recently been purchased or relocated, the chances are that the specimen hasn't acclimated itself to the new environment. Be sure to provide a bright, indirect setting with the best possible angle to the light source (overhead or nearby a window). Maintain relatively moist soil, allowing the top third to dry between waters and fertilise every two to four weeks, depending on the current season. If you still have questions about your poorly Alocasia, be sure to book a 1-to-1 Call with THE HOUSEPLANT DOCTOR™ to discuss this further!

Mould developing on the soil means two things - too little light and over-watering. Despite the harmlessness of the mould, it'll prove unsightly to most gardeners and is therefore removed once known. To remove, replace the top two inches of the soil for a fresh batch of 'Houseplant' compost. Either increase the amount of light received (no direct sunlight for the first few weeks to prevent environmental shock) or decrease the frequency of waters slightly. If the mould is accompanied by yellowing lower leaves, you may also have a case of root rot.

Origins

The Alocasia longiloba was first documented by Friedrich Anton Wilhelm Miquel in the early-mid 1800s in South-East Asia, most notably the Philippines. He used the Latin word, longilobus, in reference to the elongated lobes of the mature leaf (look at the top two pointed tips, which form a 'V' shape).

Another species named 'Alocasia lowii' also originated from the same area, first documented by William Jackson Hooker in the early 19th century. This was an accepted species for many years, primarily due to the different size of the mature leaf compared to the A. longiloba. Unfortunately, after several morphological studies, it has been revealed that the species is, in fact, the A. longiloba, possibly differentiated by separate growing conditions that have resulted in a shifted leaf-size. A. lowii was named in honour of British botanist, R.J. Lowe.

The Distribution of Alocasia longiloba.

Temperature

12° - 30°C   (54° - 86°F)
H1b  (Hardiness Zone 12)  - can be grown outdoors during the summer in a sheltered location with temperatures above 12℃  (54℉),  but is fine to remain indoors, too. If you decide to bring this plant outdoors, don't allow it to endure more than an hour of direct sunlight a day as it may result in sun-scorch. Regularly keep an eye out for pests, especially when re-introducing it back indoors.

Spread

Up to 1m in height and width, with the ultimate height being reached in around 5 - 10 years. Alocasia longiloba is best grown with overhead lighting to compliment their growth structure; locations with lateral light sources (e.g. the corner of a room) will cause stunted, lopsided growth.

Pruning

Remove yellow or dying leaves, and plant debris to encourage better-growing conditions. While pruning, always use clean scissors or shears to reduce the chance of bacterial and fungal diseases. Never cut through yellowed tissue as this may cause further damage in the likes of diseases or bacterial infections. Remember to make clean incisions as too-damaged wounds may shock the plant, causing weakened growth and a decline in health.

Propagation

Via seed or Corm Offset Division.

Basal Offset Division - Your plant will produce several basal offsets that can be separated once they have a sufficient root system, and surpass 25cm in height. If possible, water the soil 24hrs before the main event to reduce the risk of transplant shock, when its dry root systems are over-fingered. Take the plant out of its pot and place your fingers close to the nodal junction - soil may have to be removed for better access. Push the chosen offset downwards until you hear a snap. Separate the foliage and its root system away from the mother plant, mentally noting the high risk of damage. Transplant in the appropriate sized pot with a fresh batch of 'Houseplant' soil. Maintain evenly moist soil and situate it in a bright, indirect location away from any direct sunlight. After eight weeks, treat it like a normal specimen following the care tips above!
N. B. - After several years, your specimen will produce basal offsets along the stem itself - wait for the plantlet's base to swell slightly before splitting it with a knife. Follow the steps above when placing it in the soil. Don't worry if there aren't any roots, as it'll eventually produce them once the plant senses that it has been separated from its primary water-source (i.e. the mother plant).

Flowers

As Alocasia is part of the Araceae family, their flowers aren't showy. Much like a Peace Lily's flower body, their flowers consist of a white or green spathe (the spoon-like shell) with the spadix being the site of pollination. Blooms can last up to five days and is usually visible during late spring or early summer around 30cm+ from the soil line.

Repotting

Repot every two or three years using a 'Houseplant' labelled and the next sized pot with adequate drainage. Hydrate the plant 24hrs before tinkering with the roots to prevent the risk of transplant shock. For those that are situated in a darker location, add a thin layer of small grit in the pot's base to improve drainage and downplay over-watering. Click here for a detailed step-by-step guide on transplantation, or via this link to learn about repotting with root rot.

Pests & Diseases

Keep an eye out for mealybugs, spider mites, scale & thrips that'll locate themselves in the cubbyholes and undersides of the leaves. Common diseases associated with Alocasia are root rot, red leaf-spot, botrytis, powdery mildew & southern blight - click here to learn more about these issues.

Toxicity

Members of the Araceæ family typically contain poisonous calcium oxalate crystals, with Alocasia being no exception. Other members of this family include Philodendron, Zamioculcas (ZZ Plants) and Spathiphyllum (Peace Lilies). If eaten, vomiting, nausea with a loss of appetite could occur and consumption of large quantities must be dealt with quickly.

Retail Locations

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