Family Primulaceae
The greenhouse cyclamen of today is descended from the species Cyclamen persicum (syn. C. latifoUum) which is found growing wild in Greece, Turkey, Syria, the Aegean Isles, Crete and Cyprus. The species has attractive heart-shaped marbled leaves and fragrant flowers which are small, the petals being narrow and twisted on quite long stems. The colour range is usually white, rose pink and various shades of lilac. There are no bright reds and crimsons. The species exhibits considerable variation in its foliage.
It was not until early in the nineteenth century that the cyclamen became popular as a pot plant in this country, but ai this time the plants offered by nurserymen had flowers only slightly larger than the wild species.
During the first half of the nineteenth century new plants were brought into Great Britain in ever-increasing numbers and nurserymen and amateur growers were constantly striving to improve the species by cross-breeding and improving the growing conditions. It is not uncommon for cultivated plants which are constantly being interbred to develop new characteristics, and in 1870 a new race of cyclamen appeared which had large flowers. There does not seem to be any evidence that this change came about as a result of a breeding programme, and it has been suggested that intense cultivation, using the most suitable composts and ideal growing conditions, may have some bearing in the matter. A change of this kind is usually due to a mutation in the cell by an increase in the number of chromosomes or a change in the gene structure. Well-known examples of this are the Russell lupin and the Spencer sweet pea, and the results are, of course, very much improved forms almost overnight, as it were. This new development naturally stimulated the breeders and by 1875 plants had been produced which could be said to be the forerunners of the modern hybrids. At first only white and crimson shades were available but later a rose pink was raised.
In 1894 the nursery firm of Suttons introduced a salmon pink shade called 'Salmon Queen' and by crossing this with purple shades the brilliant crimsons were produced, but the flowers were rather small compared with today's plants.
This new race of large-flowered cyclamen had lost two of the desirable properties of the species, these being the fragrance of the flowers and the markings on the leaves; consequently efforts were made to restore these characteristics.
Breeders have more than succeeded with the leaf markings but with the search for fragrance the success has been much more limited, and up to the present time sweet-scented cyclamen hybrids do not compare in apprearance with the large-flowered non-fragrant hybrids either in size of flower or colour of petal.
In 1896 Vilmora introduced a strain possessing marbled leaves which he called 'Grandiflorum Zonale'. In Germany Meckel's 'Silber Blatt' (silver leaf) strain was introduced in 1904, but was by no means as ornamental as the modern silver leaf
Cydamen ptrskum. if brought into flower by late auiurnn ihis plant will flower throughout the winter to the sprint; when kept in a cool sii u.it inn varieties. In 1910 attempts were made m breed fragrant strains, and although some success was achieved the varieties did not become popular because the flowers lacked size and brilliance by comparison with the established hybrids, which still applies today, and so the search continues.
CULTIVATION
Cyclamen are grown from seed. The best times to sow are in mid-summer or mid-winter, depending on the facilities you have at your disposal. Cyclamen require a temperature range of 50-60°F(10- 15°C) for continuous growth, which means an average temperature of 55°F (I3°C). Moreover a moist environment is essential as the plants will not tolerate a dry atmosphere. If you can provide these conditions the best time to sow is in mid-summer, because it takes about 12 to 15 months to produce a really good plant. The alternative is to sow in winter, which means that by the time the seedlings are ready for potting it will be spring, and there will be no difficulty in providing good growing conditions.
You will not produce large plants by the winter, in fact some of the plants will not flower at all, and those that do will not compare with the summer-sown plant. You will however produce superb plants by the following autumn. An interesting feature of cyclamen is that its seed can be sown at almost any time of the year.
The seeds are large enough to handle and can therefore be sown separately 1 in (2.5 cm) apart (because the roots tend to spread out), and about 'A-'A in (3-6 mm) deep in either JI sowing compost or a soilless sowing compost.
The compost should be moist but not wet, because nowadays the practice is to put the seed pan (or pot) in a plastic bag which is then sealed to prevent any loss of moisture.
If the compost is too wet the seeds will rot. A minimum temperature of 60°F(15°C) is required for germination, and if this is maintained the first seedlings should appear in four to five weeks. The seed pan should then be taken out of the plastic bag and covered with a sheet of glass during the day and removed at night. It is not essential to cover with glass, but you must ensure that the surface of the compost does not dry out while the roots are still small. To have to water the pots at this stage is not desirable because if there is too much dampness the seedlings can rot. The first growth to appear is a single leaf. In due course a second leaf appears, by which time the seedlings are ready for potting in 2'A-in (6-cm) pots. Germination is usually somewhat erratic; moreover you cannot expect 100 per cent germination, it will more probably be 60-80 per cent.
When seeds are sown in mid-summer germination is usually complete after about two months, but naturally this period will be somewhat longer with winter sowing.
The seedlings must be lifted with care from seed pans because the roots are easily broken. It will be seen that a tiny corm has developed, and this should be placed just below the surface when potting in the first 2Vj-in (6-cm) pots.
It is essential for the production of a first-class plant to maintain steady continuous growth, without any checks from the time of sowing until flowering, and this is particularly true of the cyclamen.
Strive therefore to give your plants the ideal conditions they require, which in the case of cyclamen is about 55-60°F (12-15°C), a humid atmosphere and bright light but not direct sunlight. In the winter months the light intensity is often below the requirements for growth, and at such times the plants cease to grow, but if you are able to provide artificial light for nine or ten hours a day and a minimum day temperature of 50°F (10°C) growth will continue. Cyclamen are very responsive to artificial light and any plants which are developing late can be brought into flower by early winter, which would otherwise remain in bud until late winter. A suitable source of light is a warm white fluorescent tube suspended about 18 in (45 cm) above the plants.
When the 2lA-in (6-cm) pots are well rooted pot on into 3 Vz-in (9-cm) pots and later into 5-in (13-cm) pots. The compost to use for cyclamen can be either a soilless type or John Innes type, but it is important to ensure that it is free from lime and on the acid side, having a pH 6 to 6.5, also that it is an open compost which will drain easily. It is generally agreed by the specialist growers that it is not desirable to use sterilised soil for growing cyclamen, but why this should be is not explained. A rich compost is desirable, such as potting compost E2.
When potting into 3Vi-in (9-cm) pots, the corm should be positioned slightly above the surface of the compost and for the final potting in 5-in (13-cm) pots the corm should have about one third above the surface.
A well-grown cyclamen has a considerable number of leaf stems and flower stems growing out ofihe top of the corm and should water lodge in this area the corm is liable to rot. By having the corm above the surface of the compost, the chances of this happening at the time of watering are considerably lessened.
It is often recommended that cyclamen should be watered from the bottom by standing the pot in water, thus ensuring that there is no chance of water spilling onto the plant, but this method of watering has the drawback that it leaches the soluble salts out of the compost, and when the excess water runs out of the pot it carries with it valuable soluble salts. If the plant is constantly watered by this method it will not be long before the plant is short of nutrients, particularly potash which is usually present in the compost in the form of sulphate of potash, which is a water-soluble salt.
The best method is to water the plant by pointing the spout towards the side of the pot and not allowing the water level to rise above the top of the corm.
When the plants have finished flowering, the time has come to cease watering to allow the compost to dry. Cyclamen are usually allowed a short resting period during which time the leaves slowly die oif and you are left with a dry corm. It is not essential completely to dry off the plants and they can be kept growing with the compost kept fairly dry, but in an active greenhouse it is more convenient to put them under the bench and leave more room for the spring and summer plants, which will already be requiring all the room you have available.
It is usually recommended that growth should be restarted in summer but in my experience this does not leave enough growing time to get the plants into bloom bv early winter. If you fail to do this the growth during winter is very slow.
Most amateurs cannot afford to provide a greenhouse temperature of 55cF(13°C) during these months, and unless you provide ideal growing conditions during the winter months a summer start will result in your plants remaining in bud until late winter or early spring. On the other hand if you can bring the plants into bloom by early winter, this slowness of growth is an advantage, because the blooms last for weeks on end and the plants will give a good show for over four months.
By starting the plants into growth in early summer it is not difficult to achieve this. Knock the old corms out of their pots and remove all the old compost and dead roots. Repot in fresh compost with the corm about one third above the level of the compost, and water until the compost is moist, then place in a lightly shaded frame or outside in a good light position, but not a sunny spot. Leave the pots outside until early autumn, then take them into the greenhouse by which time they should be in good leaf with flower buds showing.
Plants grown from seed sown in summer are, of course, kept growing continuously until after they flower the following autumn or winter, and the same applies to winter sowings. They should be kept in the greenhouse until the early summer then put outside, sheltered from the direct rays of the sun, or in a shaded frame. In late summer put the plants back in the greenhouse.
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