It is easy to deal with an African violet that has two or three separate crowns that are actually separate plants. This sort of growth is usually the result of potting up the whole clump of plantlets produced by a leaf during propagation without separating them. When the plant is removed from its pot, as much as possible of the compost should be gently shaken away from the roots and each crown teased apart. Each crown should then be potted into the smallest possible sized pot with fresh moist compost. Preservation of humidity is not absolutely necessary in this case as the plants already have roots; however, standing the pots over a little water would be a good idea as the compost should be kept very slightly drier than normal for about one week in order that the roots have time to recover from the trauma of the plants being teased apart. In this instance the leaves would help recovery by closing their stomata to stop transpiration of water vapor for a day or so.
In the case of a plant which has been allowed to sucker from leaf axils for a long time and is overcrowded with crowns, more drastic means have to be employed. This multi-crowned plant will be very misshapen, flowering is more than likely to be sparse, and in all probability the plant will never have been repotted by its owner. Nevertheless, providing that in all other respects the plant is healthy, it would be worth dividing it into separate sucker crowns for rooting.
Firstly, the plant should be removed from its pot for ease of handling and the outer layer of old leaves should be taken off to expose some of the leaf axils where suckers are growing. These fairly large suckers may be carefully removed from the main stem by a gentle tug sideways at each rounded base; the smaller suckers may be cleanly cut away from the stem using a sharp small-bladed knife. As little damage as possible should be done to the sucker base, although any damage inflicted would not be unduly serious unless the plant was a chimera. It may be that more leaves have to be removed to expose all but the tiniest of suckers, and these are easily taken off with the point of a soft-leaded pencil; pencil is used because it leaves a smear of carbon which seals the tiny wound, thus preventing rot setting in. All suckers of a reasonable size should be potted up into small pots to develop roots and grow on. Hopefully a suckerless crown of good size would remain, to be dealt with as a necked plant.
Any plant that has had a number of outer leaves removed should be root pruned and repotted. Repotting is not the same as potting on. A repotted plant is one that has been root pruned and then potted into a clean pot of the same size with a little fresh compost, whereas potting on is a plant being potted into a pot of one size larger than the original pot. The procedure entails firstly removing the plant from its pot and scraping away any old brown scar tissue at the bottom of the stem. Then the oldest portion of the root ball, that is the lowest one third to a half part, is cut away so that the exposed neck of the stem may be lowered into the clean pot. A little fresh moist compost is put into the clean pot and the remaining root ball is placed on top, with more fresh moist compost being filled in around the exposed neck from where new roots will grow. Care should be taken with watering for a week or two, so that the new roots are not growing into over-wet compost as this might cause their tips to rot.
Normally a mature plant should be repotted at least once a year when the removal of old leaves begins to expose a necked stem. Old leaves become pale and discolored and are no help at all with plant growth, so there is no point in keeping them on a plant. By repotting, a mature African violet may continue to grow well in the same size pot for many years. This is especially useful where many plants are grown on windowsills, when it is desirable for them to be kept at a sensible size for this purpose. It has been known for an African violet that has been repotted annually to be still as beautiful as it was more than twenty years before.
A plant that has never been repotted and has a long leafless stem with a tuft of leaves on its top is termed 'long necked'. Often the stem looks gnarled with leaf scars, and is twisted and bent over the rim of its pot. In this state the ordinary repotting that has been described above is useless, and what amounts to major decapitation surgery is desperately needed by the plant -and requiring good nerves on the part of the owner.
The stem should be completely cut through with a sharp-bladed knife 0.75in (2cm) below the tuft of leaves, and any leaves in excess of eight should be taken off. The corky tissue covering old leaf scars should be gently scraped away from the stem, and the base of the latter trimmed into a cone shape. The plant crown thus formed is set into vermiculite and compost as for a sucker covered to preserve humidity for the remaining leaves, and kept in a warm position out of direct sunlight until rooted. The new plant should be weaned gradually to a lower humidity, and continued to be grown on to maturity and flowering.
It is also possible to root such a crown in water by the method used for rooting leaves in water. However, in this instance it is important that the crown is potted into compost by the time the new roots are 0.5in (1cm) long so that water roots are not grown.
The severed main stem can be kept growing in its original pot to produce suckers from leaf scars just below the cut. The old scar tissue should not be removed as this would prevent the initiation of a sucker from that point. Until tiny suckers are apparent the root ball should be kept somewhat drier than normal, but not completely dry because the roots need to be kept alive. Without leaves on the main stem to transpire, the root ball will remain moist for a longer time, but nonetheless frequent attention to the plant's moistness is needed. When the suckers are well grown, with a crown of at least six leaves, they may be carefully removed from the old stem and potted up for rooting. Growing suckers from an old stem is not really necessary, but it is interesting to do just to prove it can be done and to gain more experience of what a wonderful plant an African violet can be.
