Selenicereus oxypetalum - Copyright: @musingsofatravellingsoul
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Bright, indirect light is favourable; however, a splash of morning sun won't do too much harm. A position that offers more than two hours of strong direct light must be kept off the cards, due to their susceptibility to sun-scorch. A location within three metres of a north, east or west-facing window, or below a skylight window is the ideal areas.
Queen of the Night Cacti are best grown in moist compost, with half of the soil drying out in between waters. It's essential only to rehydrate once it becomes mostly dry as root rot, caused by over-watering, is a serious threat to those situated in a dark room. Whilst the plant is budding or in bloom, be sure to use lukewarm water to avert shocking its sensitive root systems. Under-watering symptoms include little to no new growth, a much-needed transplant and drying leaves. Over-watering symptoms, on the other hand, include yellowing leaves that soon drop off, little to no growth and root rot. These are common with too much soil moisture, an improper soil medium or deep shade. If the foliage directly above the soil line becomes brown and mushy, the chances are root rot has occurred; take stem cuttings on non-affected growth by following the tips mentioned in 'Propagation'.
As they originate from the tropics of southern Mexico, a steady level of humidity should be at the forefront of its cultivation. Introduce a humidity tray or mist the foliage during the winter to counteract the drying air, caused by operating radiators. The use of artificial humidifiers isn't needed in the summer.
Fertilise every four waters during the growing period before reducing this to every six in the autumn & winter. Although a 'Houseplant' fertiliser will still do the job, we'd recommend using a specific 'Cactus' labelled feed as it'll support the vital thirteen nutrients that this species will need to grow.
Whilst the plant is budding or in bloom, swap for a potassium-based feed, for example, 'Tomato' food, to prolong the flowering process in the spring. Never directly apply an RTU (Ready to Use) feed without a pre-water first, as this will result in root burn and yellowed leaves.
Getting a Queen of the Night Cactus to flower is very difficult because of the species' rareness to flower. A specimen will only flower once it hits maturity, which can take up to six years in some cases. As ukhouseplants been challenged many times on this subject, we've created an acronym to help you through this process - SHORT. The combination of drying soil, cooler temperatures and dark nights will contribute to better flowers in the following season. Repotting isn't mandatory, but instead might hurt the chances because of transplant shock and stress. The following steps must be taken from autumn to winter, to provide the best possible dormancy period.
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.
Avoid the use of artificial lighting at night or locations that boast temperatures higher than 18℃ (64℉).
Reduce waters so that at least three-quarters 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.
One or two feeds using 'Cactus & Succulent' Fertiliser is all that is needed for supplementation, as too nutritious soil will reduce the chance of blooms in the summer.
This one is a reminder to reduce everything - especially the 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 - 16℃ (56º - 61℉). You'll be at a significant disadvantage if the ambient temperature is kept constant throughout the year, as this species will only respond in locations that have daily fluctuations of around 5℃. Never exceed the minimum temperature as it may lead to plant death or yellowed foliage at a bare minimum.
|Time of Year||Care Requirements|
|January & February||Resting/Dormancy Period. Reduce irrigations and fertilisation.|
|March||End of Resting/Dormancy Period. Increase waters and feed using a 'Houseplant' labelled fertiliser every four waters.|
|April||Pre-Flowering Period. Use a 'Tomato' labelled feed every four waters during this period. Water once the top third of the soil dries out.|
|May & June||Flowering Period. Maintain moist soil and fortnightly potassium-based feeds.|
|July||End of the Flowering Period. Gradually decrease both water and fertiliser intake in the soil. Remove spent flowers as they wilt.|
|August & September||Water once the top third of the soil dries out. Supplement using 'Houseplant' labelled feed every six waters.|
|October - December||Resting/Dormancy Period. Reduce irrigations and fertilisation.|
Root rot is a big issue with symptoms including yellow lower leaves, stunted or softened growth - often accompanied by stem collapse. Take the plant out of the pot and inspect its root systems. Yellow roots translate to good health, however, brown and mushy sections with soggy soil is the result of over-watering. More information about addressing root rot can be found on this link.
A brown, rotten base is also another byproduct of over-watering. If the majority of the trunk has rotted over, stem cuttings must be taken to save the remaining section of the plant. Scroll down to ‘Propagation’ for more information!
For smaller compact specimens, yellowing central leaves or a naked base are products of excess moisture being allowed to sit on the foliage. Although watering from the top is acceptable, it's recommended to use the bottom-up method to reduce the chance of rotten foliage. For those that have a bare head over the soil, improve growing contains by using this method and increasing light levels. Promote a bushier appearance by taking vine cuttings and placing them halfway down into the soil once the stems reach over 5cm. Immediately remove yellowed or rotten debris as this will harbour both bacterial and fungal diseases that can both spread across to other sections of the plant.
Failed leaf or stem cuttings are a common issue among amateur gardeners, with damaged wounds or too small vines being the usual culprits. Although propagating all tropical cacti is relatively easy, people still find it hard to ace. Not only will the size of the vine dictate its success, damaging the leaves or vine can also hurt the chances of rooting. For more information about how to take vines, scroll to the 'Propagation' section of this article.
Too much sunlight will cause a red tinge to the foliage. Although Queen of the Night Cacti are best grown in locations offering just a few hours of sun, prolonged periods on non-acclimated specimens will lead to sun-scorch. If yours is a newly-purchased plant, build its tolerance to the sharp rays by increasing the amount of receivable light per week by an hour.
A lack of flowers is caused by immaturity or an insufficient dormancy period served in the winter months. Specimens will only flower once they reach maturity - which can take in the region of three to six years from a leaf cutting. Also, locations that offer near-similar temperatures all year round won't allow the plant to go dormant, resulting in poor spring growth. To achieve bud development, situate in a location that offers nighttime temperatures of around 12°C (54°F) with fewer waters. The combination of both cooler temperatures and dry soil during the colder months will help season the plant, thus leading to a better chance of flowers in the future.
Always use lukewarm water, and if you choose to use tap water, allow it to stand for at least 24hrs before application. Tropical cacti tend to be quite sensitive to temperature change, so pouring cold tap water immediately into the pot will not only ironise your roots but could even cause yellow edges, sudden flower loss and stunted growth.
The Queen of the Night Cactus, or Selenicereus oxypetalum, originates from southern Mexico and was first described by Adrian Haworth in the late 18th century as Epiphyllum oxypetalum. Epiphyllum comes from Latin words for 'upon' and 'leaf' that refers to its epiphytic nature. In contrast, Selenicereus derives from Greek to mean 'moon' (in reference to them blooming mostly at night); Oxypetalum is Latin for 'acute petals'.
10° - 26°C (50° - 78°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 any direct sunlight as it may result in sun-scorch and dehydration. Regularly keep an eye out for pests, especially when re-introducing it back indoors.
Up to 1m in height and 1m in width, with maturity taking up to eight years.
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.
Via Seed or Leaf/Stem cuttings.
A Queen of the Night Cactus will only bloom in the late spring when it reaches maturity. It's white star-shaped flower will only open for a few hours at night, despite taking several weeks to develop. Once the inflorescence begins to wilt, it becomes edible. Be sure to take photos of your specimen in bloom, as the show will only last six hours maximum!
Repot every two years in the spring, using a 'Cactus & Succulent' labelled potting mix and the next sized pot with adequate drainage. They're far better being 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 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!
Keep an eye out for mealybugs, spider mites, whitefly, scale & vine weevils. Typical diseases associated with Queen of the Night Cacti are root or leaf rot, leaf-spot disease & powdery mildew. For more information on how to address any of these issues, click on this link - Identifying Common Houseplant Pests & Diseases
Queen of the Night Cacti are classified as non-poisonous. If large quantities of the plant are eaten, vomiting, nausea and a loss of appetite could occur.
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