Queen of the Night - Selenicereus Oxypetalum


Selenicereus oxypetalum - Copyright: @musingsofatravellingsoul


Top Tips

  • Water once half of the soil dries out, reducing this further in the autumn and winter.
  • Provide a humid location. Introduce a humidity/pebble tray or mist the foliage weekly to keep the surrounding moisture high during the winter to avoid dry air. The use of artificial humidity is not needed in the summer.
  • Provide a bright location. Avoid more than two hours of direct sunlight, as well as away from excessively dark settings.
  • Supplement with houseplant feed or a general plant fertiliser, at monthly intervals.
  • Regularly check for pests, most notably Mealybugs.
  • Keep the ambient temperature above 10℃  (50℉)  throughout the year, especially if placed outdoors in the summer.
  • If you're looking to entice flowers, provide nighttime temperatures of 12℃  (54℉)  over the winter months to aid its dormancy - a cool conservatory would be the ideal location.
  • Repot every three years using a Cactus & Succulent potting mix.




Water - πŸ”ΈπŸ”Έ

Queen of the Night Cacti are best grown in moist compost, with half of the soil drying out in between waters. It's important to only rehydrate once it becomes 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 or yellow/shrivelling leaves  - remember, although they're in the cactus family, they originate in tropical locations meaning soil moisture and humidity should be generous. Over-watering symptoms include yellowing leaves that soon drop off, no or little growth and root rot. These are common with too much soil moisture, an improper soil medium or too low light.


Humidity - πŸ”ΈπŸ”ΈπŸ”Έ

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 artifice humidifiers aren't needed in the summer.


Location & Light - πŸ”ΈπŸ”Έ

Bright, indirect light is favourable; however a darker location 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 are the ideal areas.


Fertilisation - πŸ”ΈπŸ”Έ

Regularly supplement the soil using either houseplant or cactus feed, at monthly intervals. If the plant is budding, give it a helping hand by swapping its usual fertilisers for a potassium-based feed - tomato food is a good example of this. Never directly apply 'ready-to-pour' fertilisers into the soil without a pre-water first, as this could lead to the burning of roots.



Some specimens can grow up to six FEET in some cases, despite being an epiphyte (grow on trees). Copyright: @liensplantlife


Common Issues with Queen of the Night Cacti

Root rot is a big issue; typical symptoms include yellowing lower leaves, stunted or softened growth often accompanied by vine collapse. Take the plant out of the pot and inspect its root systems. Yellow roots symbolise good health, however, if it's brown and mushy with the soil being quite soggy, action must be taken immediately. More information about addressing root rot can be found on this link.

Too much sunlight will cause a red tinge to the foliage. Although these Cacti are best grown in locations offering bright light, prolonged periods of intense rays cannot be tolerated. Although the new growth will develop into its original green texture, sunburnt leaves will remain red or yellow for the rest of its functioning life.

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 it rooting. For more information about how to take vines, scroll to the 'Propagation' section of this article.

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 eight 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 seasonise the plant, thus leading to a better chance of flowers.

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 ionise your roots but could even cause yellow edges, sudden flower loss and stunted growth.



Its flower shaft will emerge from a flattened portion, reaching a length of 30cm. Copyright: @alinecbb



How to Achieve a Bloom

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 eight 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.


Sunlight

Provide a bright location with a splash of winter sun. Darker settings will significantly reduce the chance of flowers.


Hydration

Reduce watering so that the soil becomes fully dry for a week, for the prevention of root rot and to replicate its dormancy period.


Occasional Feeds

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.


Reduce Everything

This one is a reminder to reduce everything - especially the temperature.


Temperature

Reduce the temperature by around 5℃ or place in a room which is within 15℃ - 18℃  (59 - 65℉).  As most houseplants are sensitive to temperature change, we can't empathise how important this is to replicate their dormancy period. If all of the steps are fulfilled, an established specimen could produce beautiful red or pink clusters of flowers in the summer, lasting several weeks.

Time of YearCare Requirements

January & FebruaryResting/Dormancy Period. Reduce irrigations and fertilisation.
MarchEnd of Resting/Dormancy Period. Increase waters and feed using a nitrogen-based fertiliser at monthly intervals.
AprilPre-Flowering Period. Use a potassium-based feed fortnightly during this period. Water once the top their of the soil dries out.
May & JuneFlowering Period. Maintain moist soil and fortnightly potassium-based feeds.
JulyEnd of the Flowering Period. Gradually decrease both water and fertiliser intake in the soil. Remove spent flowers as they wilt.
August & SeptemberWater once the top third of the soil dries out. Supplement using houseplant feed or a general plant fertiliser, at monthly intervals.
October - December Resting/Dormancy Period. Reduce irrigations and fertilisation.




Origins

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 oxypetalumEpiphyllum 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'.


Temperature

10° - 26°C   (50° - 78°F)
H1b - can be grown outdoors in summer in a sheltered location, but is fine to remain indoors. Placing this cactus outside is very beneficial to help with its overall health. If you decide to bring the plant outdoors, do not allow it to endure more than an hour of direct sunlight a day as this will burn the leaves. Regularly keep an eye out for pests, most notably aphids.


Spread

Up to 0.8m in height and 1m in width, with maturity taking up to eight years. If you've got images of any tropical cacti that are over twenty years old, be sure to send an image of it to us via the 'Contact Me' section of this website!

Pruning

Remove yellowed or dying leaves and plant debris to encourage better growth and improve the all-round appearance. Vine cuttings can be taken to halve the vine-length of the specimen, as well as doubling your stock.

Propagation

Via seed or leaf/stem cuttings. To learn about the essentials with sowing seeds, be sure to click on this link - Seed Propagation Tips.

Soil Propagation of Leaf Cuttings

  1. Choose which leaves to use. The ideal candidates are those that show no sign of damage, pests or diseases, and have small wires roots already-attached. Cuttings that don't have any roots will still root, but it may take a little longer for its propagation.
  2. Delicately prune the whole leaf off from the plant, and cut it into several sections sideways. If you're stuck on which way to propagate the leaves, look at the image below.



  3. Prepare the pot and soil. Choosing a free-draining potting mix, for example, Cactus & Succulent Compost, provides a nice balance of moisture-retention and well-drainingness. Of course, most soils are acceptable (Houseplant or Multi-purpose compost), but try to add some extra ingredients like grit, sand and perlite to help loosen it up. If you've got any shallow and wide pots, for example a Bonsai pot, this is the time to use it. Propagating tropical cactus cuttings won't require deep soil, so try and avoid pots that are too big. Terracotta and plastic pots are both acceptable in this instance.
  4. Place the cuttings ON TOP of the moist soil. Allowing both the plant and it's wound to callous over (dry up) will kick-start the rooting process, along with the prevention of rot. Keep the cuttings on top of moist soil for a week, misting the soil and foliage on opposite days.
  5. Provide a bright, indirect location with temperatures above 18°C  (64°F) throughout this period.
  6. Then, place the cuttings into soil, submerging the bottom third. Make sure you don't set it too deeply into the soil, as this may lead to 'Blackleg' (the rotting of its base).

  7. Do NOT pat down the surrounding soil to aid support. The ideal soil conditions need to be fluffy and oxygenated, so compacting the soil will result in the suffocation of roots that'll lead to root rot. If support is needed, use a small stick or cane, but be sure NOT to condense it.
  8. Aftercare - Maintain evenly moist soil, allowing the top third to dry out in between waters. The ideal location would be in a warm, humid room within a few metres of a window, but out of direct light. After another month or two of being in the soil, treat it like a normal houseplant.


Flowers

A Queen of the Night Cactus will only bloom 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 flower 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!


Its inflorescences will only open at night, producing a sweetly-scented fragrance before wilting by the morning. Copyright: @firkingood

Repotting 

Every third summer (after the flowering process), transplant into a slightly bigger pot using Cactus & Succulent Compost. This is an excellent time to check the roots' condition, as well as propagation. As all tropical cacti are prone to root rot, have a look around the bottom half of the root ball for any brown or broken down roots. If this is the case, remove the affected areas with clean utensils and ease off with the irritations. Click on this link to learn about how to perform the perfect transplant.


Diseases & Pests

The typical diseases associated with Epiphyllum are root or leaf rot, leaf-spot disease, botrytis petal blight & powdery mildew. Keep an eye out for scale, spider mite, mealybugs & vine weevils. For more information on how to address any of these issues, click on this link.  Identifying Common Houseplant Pests & Diseases


Toxicity

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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