Jasmine polyanthum
Contents
- Top Tips
- Location, Water, Humidity & Fertilisation
- Dormancy Period & Annual Flowers
- Common Issues
- Origins, Temperature, Propagation, Repotting & Toxicity.
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Top Tips & Info
- Care Difficulty - Moderate
- Bright, indirect light with a splash of morning or evening sunlight is best - avoid excessively dark locations for maximum flowering times and overall health.
- Keep the soil evenly moist whilst in flower, using lukewarm water. Reduce waters slightly in the autumn and winter to avoid over-watering and root rot, common during its dormancy period.
- Average room humidity is more than acceptable for a Jasmine - do not situate it within three metres of an operating heat source due to the risk of browning leaf-tips.
- Feed at fortnightly intervals using a potassium-based feed (like 'Tomato' or 'Flowering Plant' fertilisers) whilst in bloom, reverting to a 'Houseplant' labelled product at monthly intervals, soon after.
- Scroll down to 'Dormancy Care & Annual Flowers' to learn more about annualising blooms.
Location & Light - 🔸🔸🔸
A location with little to no direct sun is the ideal setting for this species. Never situate a Jasmine in a dark location, due to the heightened chance of root rot and a lack of flowers. If you're worried about its location being too dark, if a newspaper can be read while having your back towards the light source, you're good to go.
In terms of the ideal room around the house, as long as the desired location is above 15ºC (59ºF) and is at least four metres away from an operating heat source, it should be accepted by the Jasmine. Do not place the plant in more than a few hours of direct sunlight as irreversible damage may occur.
Water - 🔸🔸🔸
Jasmine won't tolerate persistent droughts, especially whilst in flower. Once the top third of the soil has dried out, rehydrate the soil with lukewarm tap water. Whilst the plant is in bloom, it's essential not to use cold water as this will quickly shock the roots, causing multiple issues down the line. Reduce waters slightly during the autumn and winter months to help winterise the specimen. Under-watering symptoms include rapid flower loss, stunted growth, yellowed foliage and dry, sunken leaves; these issues are usually due to either forgetfulness, too much sunlight or too much heat. Over-watering symptoms include rotting lower leaves, yellowing leaves, a loss of buds or flowers, and root rot. Allow at least half of the soil to dry out in between waters, preventing a pool of standing water from accumulating beneath the pot to help matters. Scroll down to 'Common Issues' for more information on addressing root rot.
Humidity - 🔸🔸
Average room humidity is more than enough to occupy an indoor Jasmine, as too high humidity and poor air circulation will result in powdery mildew. Do not mist the flowers as this will cause botrytis petal blight that can spread quickly if not dealt with accordingly.
Fertilisation - 🔸🔸
Use a fertiliser high in potassium to prolong its flowers during the festive period, at fortnightly intervals - an excellent example would be a Tomato Feed. Regular fertilisers, for instance, BabyBio or Miracle-Gro, will still do the job but will favour foliar growth instead. For the rest of the year, a standard fertiliser can be used to supplement the plant, at monthly intervals.
Dormancy Care & Annual Flowers
Jasmines can produce beautiful flowers in the spring when its dormancy waters are reduced by half; those who have a cooler room without artificial light at night will also be on the upper-hand. The following steps should be performed from autumn through until early spring during a state of inactivity. Keep the roots pot-bound to add further stress onto the specimen, which in turn will significantly heighten the chance of flowering. Blooms will generally appear in the late spring but may occur in the summer in some cases.
N. B. - Be sure to 'pinch-off' the leading growths in the early spring to push the plant into developing flowers, as supposed to more greenery. You can lightly prune its top growths by an inch by just using a 'pinching' technique, whereby you remove both the leaves and the portion of the stem where the petioles are housed.
Sunlight & Location
Be sure to provide a bright location with little to no direct sunlight. Although the winter rays won't necessarily hurt the plant, be careful not to fall in the trap of sun-scorch and severe dehydration.
Place the plant outside in a shaded location during the summer once the nighttime temperatures are above 12℃ (54℉). Not only will this allow the plant to soak up some natural indirect rays, but it'll also increase the chance of bloom in the following spring. Bring the plant back indoors once the summer is over; always check for pests - most notably being Aphids that'll attack the new growth. In order for the Jasmine to fully become winterised, avoid the use of artificial lighting at night or locations that boast temperatures higher than 18℃ (64℉) when placed back indoors.
Hydration
Reduce waters so that at least half of the soil becomes dry. It's essential to keep them on the drier side to life, as they'll think that hard times are ahead and therefore will need to pass its genes on to the next generation.
Occasional Feeds
Whilst in bloom, use a Tomato feed to provide monthly nourishment of potassium; fertilisation isn't needed until the first flower stalk develops from the plant.
Reduce Everything
This is to remind you that everything needs to be reduced - especially the temperature.
Temperature
This is the most significant step; reduce the temperature down by around 5℃ compared to the summertime or place in a room that's between 13º - 15℃ (56º - 59℉). The drop in temperature should ideally last until the inflorescence finishes blooming, although it can still be transferred into the main house as long as it sits on a pebble tray. You'll be at a significant disadvantage if the ambient temperature is kept constant throughout the year, as indoor Jasmines will only respond in locations that have daily fluctuations of around 7℃. Never exceed the minimum temperature as it may lead to plant death or yellowed foliage at a bare minimum.
Common Issues with Indoor Jasmines
Heavy soil and mould developing on the soil means two things - too little light and over-watering. Despite the harmlessness, 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.
Under-watering is the second biggest issue when it comes to an indoor Jasmine. Typical signs of this include wilting, sunken leaves, rapid flower or bud drop and stunted growth. Not only will you have to be mindful of persistent droughts, think about which plant parts to keep dry. Its foliage must also remain dry at all times to prevent the development of diseases and blights. Jasmines situated in direct sunlight or within four metres of a radiator are more likely to suffer from under-watering related issues.
Too much sunlight will lead to sun scorch, with typical signs including browning or crispy leaves, dry leaf-edges, sunken leaves or stunted growth. Although too little light will cause over-watering issues, too much sunlight will be a detriment, too. If yours has fallen short of this, reduce the amount of sunlight considerably and always be mindful of environmental shock (when too locations offer too different growing conditions). Remove some of the affected leaves and increase waters slightly. Only hydrate the plant using the bottom-up method.
As mentioned before, powdery mildew and botrytis are major threats among heavy foliage plants due to the compact nature that aids the spread of the diseases. Watering above the foliage will allow excess moisture to sit in the cubbyholes of the stem, enticing harmful bacteria to thrive. Remove the affected areas and improve the growing conditions by situating the plant in a brighter location with the use of the bottom-up method of irrigation.
Never situate an indoor Jasmine in direct sunlight or within four metres of an operating heat source, for instance, a radiator or fireplace. Due to the heightened temperature, the plant will soak up far more moisture than those situated in cooler locations, increasing the chance of droughts.
Sudden flower loss can be caused by an array of different issues, including a change in location, too little hydration, too hot or cold temperatures or droughts and pests. Whilst the plant is in bloom, keep the soil evenly moist, to hydrate the thirsty work of producing flowers. Locations that are outside of the recommended temperature bracket, or have drastic fluctuations must also be kept off the cards, as Jasmines can be very sensitive to the ambient warmth that they're situated in. The final issue could be to do with pests. Although it's highly unlikely that an infestation will cause a sudden change in health, have a quick inspection for Vine Weevils (located in the soil), Spider Mites, Aphids and Mealybugs.
A lack of flowers is caused by an insufficient dormancy period, served in the winter months. Locations that offer near-similar temperatures all year round won't allow the plant to go dormant, resulting in low spring growth. To achieve, situate in a location that dips to around 12°C (54°F) with fewer waters. Allow the majority of the compost to dry out and provide a humidity tray while the radiators are operating.
Providing a taller trellis each time a Jasmine is repotted will promote better foliar and flower growth. Copyright: thesweetpetite.com
Origins
There aren't many differences between the outdoor and indoor varieties. The latter, J. polyanthum, will flower during the start of spring that'll last up to six weeks and has pinnate foliar arrangements. The species was first described by Carl Linnaeus in the mid-eighteenth century, and has natural distributions across Central Asia, from Myanmar to West China. The genus' name, Jasmine, is derived from the Arabic word, Yasmin, that refers to 'sweetly scented plants'.
The Distribution of Jasmine polyanthum
Temperature
10° - 25°C (50° - 78°F)
H1c (Hardiness Zone 11) - Can be grown outdoors between late spring and summer throughout most of the UK while nighttime temperatures are above 8℃ (46℉). If you decide to bring the 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 back indoors.
Jasmines thrive in cooler locations and will generally flower better if a good dormancy is served in winter when temperatures dip to around 12°C (54°F).
Spread
Up to 1.2m in height and 1m in width when supported by a trellis. The ultimate height will take between 4 - 6 years to achieve.
Pruning & Maintenance
Remove yellow or dying leaves, and plant debris to encourage better-growing conditions. While pruning, always use clean utensils 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.
N. B. - Allow the flowers to fully elapse (usually at the end of spring) before pruning the foliage back a third, to promote a bushier appearance and new buds for the following spring.
Propagation
Via Seed or Stem 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 phone charger wire. Each cutting should only have a few leaves leaf, above 8cm of semi-wooded stem. Situate the cutting's lower half into moist 'Houseplant' compost; 'Blackleg' can occur when the bottom wound becomes infected, resulting in propagation failure - typically caused by water-logging or deep damage. 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!
Flowers
Jasmines will flower at the start of spring if grown correctly with a good dormancy served in the autumn and winter months. Each individual flower will last up to two weeks, with the overall show lasting up to eight weeks. Supplement the plant using a fertiliser high in potassium to prolong its flowers - Tomato feed is an excellent choice. Never promote persistent droughts as this will shorten the duration of flowers. Its scent is the primary reason why Jasmines are widely cultivated indoors, filling the room with an oriental aroma that can last several weeks during the spring months.
Repotting
Repot every three years in spring using a 'Houseplant' labelled potting mix and the next sized pot with adequate drainage. Jasmines are far better potbound for several years due to the heightened risk of root rot and repotting-issues (like transplant shock), so only repot if you feel it's wholly necessary - restricted root growth will also increase the chance of blooms, too.
Hydrate the plant 24hrs before the tinkering with the roots to prevent the risk of transplant shock. For those situated in a darker location, introduce an extra amount of perlite and grit into the deeper portion of the pot to downplay over-watering risks. Click on this link for a detailed step-by-step guide on transplantation, or via this link to learn about repotting with root rot.
Book a 1-to-1 video call with Joe Bagley if you'd like a personal guide to repotting your houseplant. This will include recommending the right branded-compost and pot size, followed by a live video call whilst you transplant the specimen for step-by-step guidance and answer any further questions!
Pests & Diseases
Keep an eye out for mealybugs, aphids, scale, spider mites, fungus gnats, whitefly, blackfly, vine weevils & root mealybugs that'll locate themselves in the cubbyholes and undersides of the leaves, with the exception of the latter two in the soil. Common diseases associated with indoor Jasmines are root rot, leaf-spot disease, botrytis, rust, powdery mildew & southern blight - click here to learn more about these issues.
Toxicity
Not known to be poisonous when consumed by pets and humans. If large quantities are eaten, it may result in vomiting, nausea and a loss of appetite.
Retail Locations
Some florists & Online Stores. Specimens are likely to be found in summer outside at most garden centres. A small selection of Jasmines are sold during Christmas, but generally don't last as long as those sold earlier in the year. It's not advised to bring outdoor specimens inside as this could lead to environmental shock or the introduction of foreign pests into the home. Have a shop around online for potential specimens that explicitly state they are for indoor use only.
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