The Dragonfruits of Selenicereus undatus, formally Hylocereus undatus. Copyright: @brusorioart
Because of the water-swollen stems, Hylocereus can withstand several weeks without water. Although it’s not ideal to regularly test this ability, it’s good to know if you’re away for a few days. Allow the top third of the soil to dry out in between irrigations - once the pot begins to feel light, it's time for hydration. Reduce this further during winter to replicate their dormancy period, along with eradicating the risk of over-watering during winter. Whilst in bloom, avoid the use of cold water due to the species' sensitive nature to sudden temperature changes. Under-watering symptoms include little to no new growth, a much-needed transplant and drying 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. As with most houseplants, under-watering is far better than over-doing it, as each species has evolved to optimise water retention in case of drought. If the bottom of the stem becomes brown and mushy, the chances are root rot has occurred - keep reading to find out more.
A generous level of humidity should be at the forefront of successful cultivation. During the autumn and winter, a weekly mist or the introduction of a humidity/pebble tray will help replicate its moist habitat in the Brazilian forests. The use of artificial humidifiers aren’t needed once the heaters have been switched off in the summer months.
Although bright, indirect light is favourable, throw in some morning or evening sun to aid quality growth. 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. Alternatively, a setting where a newspaper cannot be read should also be turned away, as the chance of root rot (especially over winter) is heightened.
A location within three metres of a north, east or west-facing window, or below a skylight window are the optimum areas. For established specimens that are liable to bloom, place in a cool conservatory with nighttime temperatures around 12°C (54°F) during the autumn and winter months. This will help ease them into the dormancy period, which is critical for a flowering plant.
Supplement monthly using a houseplant or general plant fertiliser. Providing too nutritious soil will result in leggy growth in the summer.
Whilst the plant is budding or in bloom, swap for a potassium-based feed, for example tomato food, to prolong the flowering process. Never directly apply a RTU (ready to use) feed without a pre-water first, as this will result in root burn and yellowed leaves.
Root rot is a big issue with symptoms including yellow 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 soggy soil, action must be taken immediately. More information about addressing root rot can be found on this link.
A brown or rotten base is also another byproduct of over-watering - a common issue in winter. 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, commonly sped up by too little light or poor air circulation. Although watering from the top is acceptable, it's recommended to use the bottom-up method to reduce the chance of rotten foliage. For specimens that have a bare head, improve growing contains by using this method and increasing light levels slightly. Promote a bushier appearance by taking vine cuttings and placing them halfway down into the soil. 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 Hylocereus 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.
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.
Established specimens (2yrs +) may bloom during the summer if its previous dormancy period has been served well in the previous winter. 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, cool temperatures and darker nights will contribute to a potential bloom 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 in autumn and winter to provide the best possible resting period.
Provide a bright location with a splash of winter sun; darker settings will significantly reduce the chance of flowers.
Reduce watering so that the soil becomes almost dry for a week, for the prevention of root rot and to replicate its dormancy period.
One or two feeds using Cactus & Succulent Fertiliser is all that is needed for supplementation, as too nutritious soil will reduce the chance of buds.
This one is a reminder to reduce everything - especially the temperature.
Reduce the temperature by around 5℃ or place in a room which is within 12 - 15℃ (54 - 59℉). 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 Year||Care Requirements|
|January & February||Resting/Dormancy Period. Reduce irrigations and fertilisation.|
|March||End of Resting/Dormancy Period. Increase waters and feed using a nitrogen-based fertiliser at monthly intervals.|
|April||Pre-Flowering Period. Use a potassium-based feed fortnightly during this period. Water once the top their 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 feed or a general plant fertiliser, at monthly intervals.|
|October - December||Resting/Dormancy Period. Reduce irrigations and fertilisation.|
If a matured Hylocereus hasn’t flowered during the spring or summer, it's most likely due to incorrect care and its environment throughout the year. During the winter, reduce irrigations so that the soil almost dries out, along with reducing the temperature a few degrees. Provide an area that has at least twelve hours of complete darkness, with an absence of artificial light during the night. The buds may start to drop off if it endures persistent droughts or has been relocated in another room. The table above shows a basic timetable in which you can follow to significantly increase the chance of flowers during the spring.
The original name, Hylocereus is an epiphytic or lithophytic genus originating from Central America. It was first described by Britton & Rose in the early 20th century, using the Greek and Latin words hyle, meaning wood, and cereus, referring to its 'waxy' nature. The current name of the species, Selenicereus undatus, also originates from Latin, with the first section translating to 'moon' (Selḗnē). The species epithet, undatus, can be translated to 'wavy edges' that is in reference to the rib-like structure of the stem.
10°C - 26°C (50° - 78°F)
H1b - can be grown outdoors in summer in a sheltered location, but is fine to remain indoors. Placing it 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 and vine weevils in the soil.
Up to 3m 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 via the 'Contact Me' section of this website!
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.
Via seed or leaf & stem cuttings. To learn about the essentials with sowing seeds, be sure to click on this link - Seed Propagation Tips.
Hylocereus will bud in the summer with rosette-shaped flowers, sporting either red, yellow, pink or white appearances. Each flower will take several weeks to develop, lasting only a few days once opened. Most hybrids or species will produce a sweet-smelling fragrance that'll be most prominent at night. Be sure to take photos of your specimen in bloom, as the flowers will only last a few days!
If pollination is successful, the flowers' ovules will develop into Dragron Fruits. For those who aren't aware, Dragon Fruits, or better known in Asia as Pitahaya (Pitaya), can boast a whole range of health-benefits, including Vitamin B2 & C, Iron and Magnesium. The outer shell and central pulp (flesh) is also BEAUTIFUL and edible - so have a look at the images below!
Transplant every two summers 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.
Typical diseases associated with Hylocereus 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
Hylocereus are classified as non-poisonous. If large quantities of the plant are eaten, vomiting, nausea and a loss of appetite could occur.