Christmas cactus (Schlumbergera)
Schlumbergera truncata and S. × buckleyi are the two species of epiphytic cacti that are both commonly known as Christmas cactus. So called because they flower from late November to late January, they give a wonderful Christmas display or are an ideal Christmas gift.
Botanical name: Schlumbergera truncata and S. × buckleyi
Group: Houseplant, cacti and succulents
Flowering time: Late November to late January
Planting time: Late March
Height and spread: 45cm (18in) by 45cm (18in)
Aspect: Bright but avoiding direct scorching sun light.
Hardiness: Frost tender (min 10°C/50°F)
Schlumbergera grow naturally in jungle-type woodlands attached to trees. They prefer a semi-shade situation as oppose to a full sun aspect of desert-dwelling cacti. An ideal situation would be well-lit yet out of direct sunlight with a humid atmosphere. Improve humidity by using gravel-filled saucers to place your plants upon and keep this moist.
Re-pot once a year (or at least every two years) to maintain healthy growth. This can be done at the end of March, which is the beginning of their growing season. Use a standard cactus compost or a loam based compost such as John Innes No 2 with added leafmould (or peat substitute) and grit to help improve the drainage. When potting on, choose only a slightly larger container as they like to be snug in a small pot.
- After flowering a resting period is required. From late January to late March, reduce the watering to only occasionally so that the compost does not completely dry out and reduce the temperature to 12-15°C (55-59°F). This can be done easily by moving to a cooler room
- The growing season is from April-September; increase the watering and start feeding with a houseplant liquid feed. During the growing season maintain temperature of 18-20°C (65-69°F) if possible
- During the summer months, when the risk of frost has past, they can be placed outside. This will help to ripen new growth and encourages flowering. Keep them in a shady spot and protect from slugs
- From mid-September the flowering buds start to develop with shortening days and a reduction in temperature. The watering and temperature should be reduced (as before) with a second resting period. But only until the flowering buds have formed, then increase the temperature back to 18-20°C (65-69°F) and resume regular watering
- Your plant should then flower and give you a wonderful display. Exact temperatures are not critical to promote flowering provided there are two resting periods with a reduction in watering and temperature
Pruning and training
Schlumbergera require little or no pruning, but they can get a bit leggy and old plants can become congested. To help the plant bush-up remove the tips and, with congested plants, remove a few of the oldest and most damaged stems. Always remove whole segments of the leaf-like stems; this will leave you with a nicer looking plant.
Propagating schlumbergera from cuttings is nice and easy, and great fun for children to do.
- The segmented leaf-like stems make the cuttings robust and easy to handle
- In May remove terminal (tip) or lower sections made up of two or three sections. Allow them to dry out indoors for a day or two, so that the basal wound has dried and begun to heal
- Insert the cuttings into a 50:50 mix of 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 them upright. If inserted too deeply they will rot off
- Keep them in a light spot that is out of direct sunlight at a temperature of 18-24°C (65-69°F). Water very sparingly and mist occasionally
- The cuttings can take three to 12 weeks to root. Once they are well rooted pot them on individually
To produce seed these cacti need to cross pollinate with a different species or cultivar of Schlumbergera. Use an artist's brush to transfer the pollen from a fully open flower from 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. It can take 3-4 years for a plant to be raised from the resulting seed. As these seedlings will be hybrids, expect their colour forms to be different from the parent plant.
Schlumbergera are pretty much pest and disease free with only mealybug being a common pest. However they do have a few physical and cultivation problems.
Shrivelling of the stems can be caused by the plant being in a too hot and sunny situation. However it is often due to root deterioration cause by over or under watering.
Scorch; discolours and damages the stems and is caused by the plant being placed in a situation that is too hot and sunny. These are not desert cacti and would naturally grow in woodland in dappled shade.
Non-flowering could be due to the day length not shortening or/and the temperatures not dropping to mimic autumn. For example, if the plant is near an artificial light source after dark and the temperature doesn’t drop below 18°C.
Flower bud dropping is usually cause by fluctuating temperatures. Too hot by day too cold by night. However, overwatering can also cause flower buds to drop. Plants exposed to cold in florists, at garden centres or in the car are also vulnerable.
Late-flowering; can occur when the temperature has remained to high into autumn.
General poor growth can be a sign of over potting and the pot is too large for the plant; they do like to be snug in a pot. Remove the pot to check on root development. If there is little or no sign of new growth, with minimum disturbance remove excess compost and carefully put it into a smaller pot. This action should encourage new root grow and recovery.
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