Polyscias - Dinner Plate Aralia
Top Tips & Info
- Care Difficulty - Moderate
- Situate Polyscias in a location that presents a few hours of off-peak sunlight in morning or evening, especially in the winter.
- Water once the top few inches of the soil dries out, reducing this further in the autumn and winter.
- Provide a humid location by introducing a pebble tray to keep the surrounding moisture high and stable throughout the year.
- Fertilise using a 'Houseplant' labelled feed every four waters in the spring and summer, reducing this to every six in the colder months.
- Regularly check for pests, most notably Mealybugs and Spider Mites that'll be located in the foliage's cubbyholes.
- Repot every two years using a 'Houseplant' potting mix and the next sized pot.
Location & Light
A location with around two hours of morning or evening sun is ideal for this plant. Although the sunlight is highly beneficial for its health, over-exposure will result in sun-scorch that'll lead to bleached leaves. Alternatively, avoid situating one in an overly shady location that's several metres from a window due to the heightened chance of root rot and mouldy soil. If you're worried about its setting being too dark, if a newspaper can be read while having your back towards the light source, you're good to go.
A room that offers a few hours of either morning or evening sun is vital for good, quality growth; examples of this are near to a south-facing window, or in a conservatory. Avoid locating the specimen more than four metres away from a north-facing window to downplay the risk of over-watering.
An under-watered Polyscias is only slightly better than an over-watered one. Once around a third of the soil begins to dry, give the plant another good water, allowing the excess water to drain freely beneath. Always use lukewarm water, and if you choose to use tap water, allow it to stand for at least 24hrs before application. The roots systems tend to be quite sensitive to temperature change, so pouring cold tap water immediately into the pot will not only alienate your roots, but it could even damage the plant's overall health. Under-watering symptoms include curling or yellowing leaves and sudden lower leaf loss; these issues are either due to much needed repot, forgetfulness or too much sunlight/heat. Over-watering symptoms include rapidly yellowing leaves, stunted growth and a collapsed stem. Over-watering is commonly caused by too little light/heat or a lack of dry soil in between irrigations.
Create a humidity tray to provide a moist and stable environment for your plant. If the surrounding saturation is too low or the heat too high, its foliage may start to brown over and curl, especially in direct sunlight. Hose the foliage down from time to time to hydrate the leaves and keep the dust levels down.
Feed every four waters during the growing period and every six in the autumn and winter, using a 'Houseplant' labelled fertiliser. Avoid over-supplementation as a combination of excess fertiliser salts and burning roots will significantly affect its overall health.
Common Issues with Polyscias
Inconsistent watering which involves droughts and prolonged water-logging will not be accepted by a Polyscias, resulting in root rot, foliage decline and stunted growth. For those that are grown in brightly lit spots, only allow a third of the soil to dry out in between waterings, with darker locations allowing over half. If you're a forgetful gardener, set up a watering-rota so that it prompts you to re-hydrate efficiently.
Root rot is a common issue among specimens sat in too dark environments with prolonged soil moisture. Symptoms include rapidly yellowing leaves, mouldy soil, stunted growth and a rotten brown base. Take the plant out of the pot and inspect health below the soil line. If the roots sport a yellow tinge, you're good to go, but if they're brown and mushy, action must be taken immediately.
Lower leaf loss is a common and significant issue among gardeners. This unfortunate phenomenon could be a product of several different problems, most notably being dark locations, water-related abuse or environmental shock. Introduce the plant to a more well-lit area with a splash of off-peak sunlight; if caught in time, the leaf loss should stop within a week. If you feel that you're watering habits aren't up to scratch, familiarise yourself with our care tips provided at the top of this article. It's always best to under-water this species than over-do it, purely on its poor ability to endure continued sogginess. The final culprit could be down to a sudden relocation; if you've recently purchased the specimen, the chances are it is still acclimatising to the new environment. Although this shouldn't happen, a vastly different setting will cause sudden foliage loss and stunted growth. You'll have two options of either waiting it out or presenting a more Polyscias-friendly environment, mentioned in the 'Location & Light' section.
If your specimen is located in a dark environment with mould developing on the soil's surface, use a chopstick to stab the soil in various areas gently. You should aim to enter the compost between the base of the plant and the pot's edge, as failure to do so may lead to damaging its lower portion. Leave the holes open for a few days before re-surfacing the soil to avoid it becoming overly dry. Not only will the gentle shift in the soil's structure mimic the work of small invertebrates in the wild (worms, etc.), but it'll also add oxygen back into the soil, thus reducing the risk of root rot. Repeat this monthly, or whenever you feel the potting-mix isn't drying out quickly enough.
Spider Mites are small, near-transparent critters, that'll slowly suck out the chlorophyll out of the leaves. Have a check under the leaves, most notably along the midrib, for small webs and gritty yellow bumps. Click here to read our article about the eradicating Spider Mites, along with some extra tips that you may not find elsewhere!
Too low humidity can cause browning tips with yellow halos on juvenile leaves. 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 while the heaters are active to create a stable environment. The browning of leaf-tips on older leaves is wholly natural and is the product of extensive photosynthesis during its life.
The genus, Polyscias, was first described in 1775 by Georg & Johann Forster during a year-long voyage around the world with Captain James Cook. This trip proved fundamental for the popularity and demand for Pacific plants, with Norfolk Pines & Kentia Palms becoming popular throughout the 19th-century. The name Polyscias derives from Greek, with 'poly' meaning many and the 'scias' translating to shade, in reference to their growth habits.
The most popular species, P. scutellaria 'Fabian', was initially classified 'Crassula scutellaria' by Nicolaas Burman in 1768, before switching genera until its final resting place in Polyscias in 1948. 'Scutellaria' is derived from Latin, translating to 'a small dish, tray or platter", which is in reference to the shape of the calyx.
15° - 32°C (59° - 90°F)
H1a (Hardiness Zone 13) - must be grown indoors or under glass all year round. Never allow temperatures to dip below 15℃ or permanent damage may occur in the likes of flower loss, stunted growth and yellowed leaves.
Up to 2m in height and 0.7m in width. The ultimate height will take between 5 - 10 years to achieve, with 8cm of new growth per season.
Pruning & Maintenance
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.
Via Seed or 'Stem & Eye' Cuttings.
Stem & Eye Cuttings (Moderate) - This method of propagation is troublesome without the aid of bottom-heat and a controlled environment. Choose the healthiest, most established stems that are wooded, yet still juvenile enough to bend slightly, being just thicker than a pencil. Each cutting should only have ONE leaf, and a small portion of the stem to either side of the node. Cut directly below a node using a clean knife to reduce bacteria count. Situate the cutting into moist 'Houseplant' compost, with the only the leaf sticking out of the soil. Blackleg can occur when the bottom wound becomes infected, resulting in propagation failure - typically caused by water-logging or a too-damaged wound. Maintain bright light and evenly moist soil with the avoidance of direct sunlight or cold draughts. Wrap the pot (& foliage) in a transparent bag or within a miniature greenhouse, and provide bottom heat of temperatures above 18°C (54°F). Remove the bag and place into individual 7cm pots once the second new leaf emerges. Follow the same care routines, as mentioned in the article's top half. This method will take up to five months, so patience and the correct environment are paramount for success!
Although Polyscias will produce small clusters of white flowers during spring or summer, it's highly unusual for them to bloom in a domestic environment.
Repot every three years in the spring using a 'Houseplant' labelled compost 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.
Pests & Diseases
Keep an eye out for mealybugs, spider mites, scale, thrips & whitefly that'll locate themselves in the cubbyholes and undersides of the leaves. Common diseases are root rot, leaf-spot disease, botrytis, powdery mildew & southern blight.
This plant is classified as poisonous. If parts of the plants are eaten, vomiting, nausea and a loss of appetite could occur. Consumption of large quantities must be dealt with quickly - acquire medical assistance for further information.