Golden Rebutia/Rebutia marsoneri
One of the first groups ofto flower each year are the Rebutias. They are small-growing plants and are quite short-lived (up to about 15 years). Plants will flower when only 1-2 years old, and it is fascinating to see a plant that is only about 1cm (1/2in) in diameter with 3-4 flowers of about 2cm (1in) in diameter.
Most Rebutias make small mounds of bright green heads with short, fairly fine spines, the flowers appearing towards the base of the plant. These plants tend to grow early in the year. If given a little water in February and a minimum temperature of about 10°C (50°F), they should come into growth and flower in April-May. If kept colder and drier, flowering will probably be delayed until June.
The Golden Rebutia will tolerate temperatures down to 5°C (41°F) if kept fairly dry. It benefits from good ventilation, but not draughts.
This plant requires a bright situation at all times, but will benefit from being shaded from the mid Summer sun. It will grow well on most windowsills.
Water well during the Spring and Summer, allowing theto dry before watering again. During the Autumn and Winter, keep the plant fairly dry, giving only enough water to prevent shrivelling. The Golden Rebutia will soon rot if kept wet at lower temperatures.
Rebutia marsoneri comes from arid areas and will benefit from a dry atmosphere.
Feed every 1-2 weeks during the Spring and Summer with afood, or one recommended for tomatoes at about half strength.
do best in a well-drained compost containing about one third grit. Repot at least every two years. Rebutias are among the easiest of cacti to grow from seed. Old Rebutias can become untidy, so it is a good idea to try to pollinate the flowers with a small brush. Some species seem to be self-fertile, while others are not and crossing them with other plants is the best idea. Try cross-pollinating different coloured species; some of the hybrids have beautiful coloured flowers.
Sow seed in January in a warm, bright spot: germination should occur in 2-6 weeks depending on temperature. Keep the seeds moist until germination has taken place and then just damp. In April, they can be treated like adult plants, and by the following Spring one or two might even flower.
Rebutia sometimes suffer from a pitted brown marking of the skin. The cause is not known, but plants suffering from malnutrition seem more affected than well-grown ones. If the plants are fed well in Summer, the problem will probably not recur, but if it persists, it is best to replace the plant.
Red Spider Mite is the major pest and the first sign of attack is a browning of the growing point. Isolate and treat with systemic insecticide. Badly affected plants should be burned.