There are a number of reasons for African violets refusing to flower. Although the most frequently quoted reason is “lack of light”, that is by no means the only possible reason. Consider the following, all of which are equally important.
It is unreasonable to expect a plant that is not healthy to flower abundantly, so consider the health of the plant. If it is wilting, or has yellowed or lack-lustre leaves, don’t expect much from it in the way of flowers.
If there are any infestations or diseases in the African violet, the result may well be reduced flowering.
If the plant is not growing strongly it will not flower. Flowers are produced from the leaf axils (the bit where the leaves meet the main stem). If no new leaves are coming, there is nowhere from which flowers can come.
If a rosette variety of African violet should be allowed to produce lots of side-shoots (suckers), it will often stop flowering. All African violets except the trailing types should have one central growing point with all the leaves and flowers radiating out like the spokes of a wheel. If the growing point is damaged or removed, the plant will stop flowering until it has grown another crown.
If you have not repotted your plant in the last twelve months, it may continue to flower to some extent, but is unlikely to do as well as plants that receive regular attention.
If you have not applied any fertiliser to your plant it cannot continue to be healthy and flowering.
If you have consistently used only a fertiliser with high nitrogen content your plant will produce strong leaf growth at the expense of heavy flowering.
If the plant has suffered from being too dry too often the tiny root hairs that draw moisture and fertiliser from the potting mix will die and the plant will not flower.
If the growing conditions are not satisfactory, the plant will not flower well. That means appropriate light, temperature and humidity.
Sounds complicated? Not really. A person who hasn’t satisfactory food, clothing and shelter won’t thrive either.
Pot growing produces unnatural conditions for plants, and, where in the ground they may fend for themselves to some extent, in a pot you need to give them a helping hand. So here is what to do.
Wilting, yellow “off-colour” African violet plants can be caused by poor watering practices, insect infestation, too little fertiliser, potting mix that holds too much water or is otherwise unsatisfactory. Plants that seem otherwise healthy but have a plethora of leaves growing in an untidy pattern choking the production of flowers just need a little grooming.
Repot your plant. This will stimulate growth. Do it in the warmer months of the year, preferably spring.
When repotting, remove all crowns except the centre one, and outside leaves that are old, tired or unlikely to produce flowers. Remember that flowers will come from the axils of newly grown leaves.
Loosen the old potting mix away from the roots. Trim the roots so that the African violet can be replanted in a squat pot no wider than 100 mm (4 inches) across.
Any bare stem where leaves have been removed should be scraped gently to expose green tissue.
Repot in a clean pot with the bottom leaves level with the new potting mix. Best results will be achieved if African violets are repotted each year.
Keep your African violets evenly damp and fertilised to get satisfactory growth. The easy way to do this is by wick-watering. For a plant that has been repotted, use plain water for the first few weeks. After that, appropriate liquid fertiliser should be used, diluted in the water each time the plant is watered, or in the wick-watering reservoir. Fertilisers high in phosphorus promote flowering and should be preferred. There are many suitable African violet fertilisers on the market.
Examine your African violets regularly for any signs of pests or disease. Common problems are thrip (in the flowers), mites (too small to be seen by the naked eye, they destroy the centre of the plant), and soil mealy bugs (slow moving creatures, which infest the root system, where they suck the sap of the plant).
If thrip are present in the flowers, remove all flowers and buds and keep them removed for a month or two to break the thrip cycle.
Plants suffering from mites or mealy bugs are better destroyed. A leaf may be taken for propagation. Disinfect and wash well before planting.
African violets are grown as indoor plants because they thrive in conditions similar to those enjoyed by most people. Temperatures of 18-25 degrees C. are ideal, but a much wider range than that can be endured. Humidity of at least 55% is satisfactory, but for reasonably short periods the plants can survive much lower. For adequate light, use the brightest position you can finding your home, just short of direct afternoon direct sun. Within 450 mm (18 inches) of a window is satisfactory. A lace curtain, venetian blinds or similar can be used to break up direct sun, so that the plants are not scorched.
This article appeared in the November 2006 edition of the Central Coast African Violet Club’s Newsletter, and more recently on that Club's website. Following the disbandment of the Central Coast African Violet Club in 2010 the article is now available here, with permission, for your information.