How to grow Christmas cactus

What are Christmas cacti?

Christmas cacti (Schlumbergera) have long been popular as houseplants, as they’re easy to grow and put on a spectacular flowering display in winter. The flowers appear at the tip of each stem, usually in shades of red, pink or white. Even when not in flower, the long, flat, segmented stems make an attractive evergreen cascade, ideal in a hanging planter or on a windowsill. These plants can be very long lived, and the more stems they develop over the years, the more flowers they’ll produce.
 
Christmas cacti come originally from tropical rainforests, where they grow in dappled light and warm, humid conditions. So unlike desert-dwelling cacti, keep them out of strong sunshine and provide regular water and, ideally, humid air.

Choosing Christmas cacti

There are two species of Christmas cactus – Schlumbergera truncata and Schlumbergera × buckleyi – and many cultivars. They offer a wide choice of flower colours, in various shades and combinations of pink, mauve, red and white, sometimes with tinges of yellow or orange. 
 
Schlumbergera × buckleyi has an RHS Award of Garden Merit, which means it is recommended by our experts as being a reliably good performer.

Buying Christmas cacti

Christmas cacti are readily available from most houseplant retailers in the run-up to the festive season, when they’re in flower. At other times of year, they can usually be bought from larger houseplant retailers. They’re mainly sold as young plants and are relatively inexpensive.
 
Choose a plant that still has plenty of buds, rather than one in full flower, as the display will last longer. Also check that the plant isn’t in a cold, draughty location in the shop, and keep it well protected on the journey home, as low temperatures can cause the buds to drop.

Newly bought Christmas cacti can usually be kept in their original pot for a couple of years. After that, repot every year or two, once the roots have filled their pot, to maintain healthy growth. Repot at the end of March, which is the beginning of their growing season: 

• Choose a pot that is only a slightly larger, as these plants like to be snug in a small pot

• Use a standard cactus compost or a peat-free loam-based compost, such as peat-free John Innes No. 2, with added leafmould and grit to improve the drainage

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Christmas cacti are easy to look after as houseplants, but to ensure flowering, give them two rest periods per year – a month or two of cooler temperatures and less watering. These should be in the run-up to bud-formation in early autumn and again after flowering in late winter. 

Location

Christmas cacti grow naturally in warm, humid rainforests, in dappled shade. So in our homes they like indirect or filtered light. An east-facing windowsill is usually ideal. Unlike desert-dwelling cacti, they dislike full sun or very high temperatures. 
 
Move them to a cooler location (see Temperature, below) in autumn and again after flowering, to give them a rest period. 
 
During the summer months, they can be moved outside into a warm, sheltered, shady spot. This will help to ripen new growth and encourage flowering. Keep them out of full sun, protect them from slugs and snails, and bring them back indoors at the end of summer, before temperatures start to drop.

Temperature

During the growing season (spring and summer) and while in flower in winter, Christmas cacti prefer a pleasantly warm 18–20°C (65–69°F).
 
To encourage flowering, they also need two periods of cooler temperatures, at 12–15°C (55–59°F:

• in autumn, from mid-September until the buds start to appear

• after flowering, from late January to late March  

This temperature reduction can be achieved by moving the plant to a cooler room, or, if grown on a windowsill away from heat sources, the temperature may dip naturally. Exact temperatures aren’t critical to promote flowering, but there should be a distinct drop.

Watering

Water regularly from April to September, keeping the compost moist but never waterlogged. Let any excess water drain away. The roots may rot if left sitting in damp compost.
 
These plants need two rest periods of reduced watering per year, to encourage flowering:

• in autumn, from mid-September until the buds start to develop with the shortening days. Once you see the flower buds, resume watering until the flowers fade. Take care not to overwater

• after flowering, from late January to late March. Then return to watering regularly through spring and summer, until mid-September 

During these two rest periods, let the top few centimetres of compost dry out between waterings, but never let it dry out entirely. 

Humidity

These topical plants enjoy a humid atmosphere. Mist them regularly and stand the pot on a tray of damp gravel, making sure the compost doesn’t become waterlogged. See our quick video guide for more tips: 

Feeding

To boost growth, apply a liquid houseplant feed from April to the end of September.

Encourage flowering

In autumn, give plants a cooler spell, at 12–15°C (55–59°F, and water less often. This, along with the natural reduction in day-length, helps to stimulate bud formation. As soon as you spot the first flower buds, move the plant back to its usual location at 18–20°C (65–69°F) and water regularly. 

Plants need another similarly cooler, drier spell after flowering.

The flowers only form on the stem tip, so for more flowers, the plant needs to have more stems. These will grow naturally over time, but you can also encourage stems to branch by removing a few of the tip segments in spring. These can then be used as cuttings (see Propagation, below) to create new plants.

Christmas cacti generally require little or no pruning, gradually forming an increasingly large clump of long, cascading stems over time. 
 
But plants can sometimes get a bit long and straggly. If so, encourage the stems to branch and form a bushier plant by removing some of the end segments on any leggy stems in spring after flowering. Branching will also give you more flowers, as they only form on stem tips. 
 
If you have an old, congested plant, you can remove a few of the oldest and most damaged stems occasionally in spring, at any of the joints between segments. Always remove whole segments, to keep the plant looking natural.

Growing Christmas cacti from cuttings

It’s easy to grow new plants from cuttings in May:

• Take your cutting from the end of a stem, removing a couple of segments – snap them off at a joint or carefully cut between the segments. Leave the cutting for a day or two, to let the basal wound dry out 

• Fill a pot with a 50:50 mix of peat-free seed/cuttings compost and sharp sand 

• Push the bottom of the cutting into the compost about 1cm (½in) deep or just deep enough to keep it upright. If inserted too deeply it will be more likely to rot. You can put several cuttings into one pot, around the outside

• Keep the pot in a bright location, out of direct sun and at 18–24°C (65–69°F). Water very sparingly and mist occasionally

• Cuttings can take from 3 to 12 weeks to root. Once well rooted, pot them up individually

Growing Christmas cacti from seed

To produce seeds, these cacti need to cross-pollinate with a different species or cultivar of Schlumbergera. Use an artist’s paintbrush to transfer pollen from a fully open flower on one plant to the stigma (the most protruding part of the flower and usually pink in colour) of the other plant and vice versa. Grape-like fruits will form, from which seeds can be harvested once ripe. 
 
Sow the seeds in warm conditions, ideally in a heated propagator. The seedlings need bright but indirect light at 18–24°C (65–69°F). Water regularly and mist occasionally.
 
Growth tends to be slow, so it can take three or four years for a seed-raised plant to become well-established. As these plants will be hybrids, their flower colours may be different from the parent plant.

Christmas cacti are generally robust, adaptable and tolerant plants, able to withstand occasional neglect. But if not given the right conditions, plants may have poor growth or flowering problems, including: 

• No flowers or few flowers – could be due to the day-length not shortening and/or the temperature not dropping to mimic autumn. For example, if the plant is near an artificial light source after dark and/or the temperature doesn’t fall below 18°C (65°F)

• Flower buds drop – usually caused by fluctuating temperatures, too hot by day and too cold by night. When buying a new plant, make sure it isn’t displayed in the shop in a cold, draughty spot and keep it well protected on the journey home. Overwatering can also cause buds to drop

• Late flowering – can occur when the temperature has remained too high into autumn

• Shrivelled stems – often due to root deterioration caused by over- or underwatering, or too much heat or direct sun

• Discoloured stems – scorching can occur if the plant is too hot or gets direct midday sun. Bear in mind that these are not desert cacti – they come from tropical forests, where they grow in dappled shade

• General poor growth – can be a sign that the pot is too large for the plant (see overpotting). Christmas cacti do like to be snug in their pot. Remove the pot to check on root development – if there’s little or no sign of new growth, gently remove the excess compost and put the plant into a smaller pot. This should encourage new root grow and recovery

Also check plants occasionally for insects, such as mealybugs.