JARS v64n1 - Cyclamen: A Perfect Companion Plant for Rhododendrons

Cyclamen: A Perfect Companion Plant for Rhododendrons
Bill Bischoff
Surrey, BC, Canada

Let me introduce you to one of the small wonders of the Mediterranean area, the beautiful Cyclamen , all 22 species of them. As the cacti are native to the Americas, so are Cyclamen true children of the lands between northern Africa and southern Europe.
Cyclamen grow throughout the Mediterranean region. From the west on the Balearic Islands; north to southern France, northern Italy, Switzerland, Germany, Austria and the southern mountains of Poland; northeast to the south west coast of the Caspian Sea in northern Iran; east to Greece, Turkey, Lebanon, and Israel; and south, to many of the Mediterranean islands, several locations in northern Africa, and one location in Somalia (Horn of Africa). When one looks at the area of distribution of Cyclamen , one sees that studying Cyclamen is also a lesson in geography and ancient history, as several species are named for their locations, sometimes using ancient place names. Also, in several locations more than one species grows.

That Cyclamen have flourished in the Mediterranean for a very long time is quite evident from the remarkable growing habits of these plants. So well adapted are they to the climate of this area that they have become summer dormant for the most part. Summer dormancy may be a rather difficult concept for many North American gardeners to accept. However, most Cyclamen are indeed without leaves and flowers for several weeks every summer. To make up for this, they are evergreen throughout winter. The exception is one species, C. purpurascens , the northern most growing species, which is mostly evergreen year round. Two more extremes are the species C. repandum and C. peloponnesiacum , which are dormant from July until next March.

Cyclamen as ground cover.
Cyclamen as ground cover.
Photo by Carla Bischoff

In northwest North America, we enjoy a climate that as far as Cyclamen are concerned could be considered as medium Mediterranean. It is warmer in the winter than their coldest northern growing areas and cooler in the summer than the rather hot Mediterranean islands and northern Africa. In the hottest growing areas, Cyclamen grow mostly at higher elevations, where they at least enjoy cooler nights. Our rather dry summers also suit them well, as it duplicates the condition in their respective native habitats. To really make them feel welcome in culture, use only the best draining mix to grow them in: lava rock, perlite, # 3 turkey grit (which can be used also as top-dressing), and very course compost. Most important, avoid having them stand in water for any length of time.

In succession, the different Cyclamen species will flower from mid January to mid December, with the occasional flower of C. purpurascens as late as Christmas. A dormancy period is a definite adaptation to the very dry and hot summer climate of the Mediterranean.
Of the 22 recognized Cyclamen species, 18 are hardy enough to be considered outdoor plants in coastal British Columbia, Washington and Oregon. To successfully cultivate these plants, first familiarize yourself with their origin. Plants from north of the Alps withstand longer cold and wet conditions than plants from the hot and dry Mediterranean islands.

Most Cyclamen are shade tolerant, and so can be planted under trees and bushes, including rhododendrons. They are also very pH tolerant, although in extreme cases, a small top-dressing of crushed oyster shells will correct an over acidic condition without harming nearby acid-loving plants. When grown in full sun, expect smaller leaves, but more distinct leaf patterns. Once established in a garden, these plants will surprise one by where they decide to locate themselves as they naturalise. It is therefore important to be careful when weeding, so as not to rip seedlings out.

Most of us are likely to be familiar with the "supermarket" Cyclamen , which has shooting-star flowers, with flower petals bent back and upward. The leaves of these plants are beautifully marked, and all plants seem to have different leaf patterns. This is C. persicum , which is not hardy as an outdoor plant in Canada or other areas with freezing conditions. Its name might imply it's from Persia, i.e., Iran, but it comes from north-western Syria and eastern Turkey, which years ago were under Persian influence. These supermarket plants are highly cultivated and inbred, which results in gorgeous plants that are rather susceptible to disease, making home-cultivation difficult. Until you get more familiar with this species of Cyclamen , its best to treat them as cut flowers and not try to keep them alive over the long-term. Wild plants of this species are vastly different and are very resistant to pests and disease, but even C. persicum in the wild are not reliably hardy at temperatures below freezing, and so only pot-culture is advised. This will allow them to be moved indoors when freezing temperatures occur outside. Potted plants of this species (not inbred cultivars) can be placed in direct sun outside except for the coldest weeks of winter. Their almost infinite leaf coloration and patterns is attractive, and their flower colour is wide-ranging.

Among the other species, C. coum is perhaps the most available and hardiest winter flowering species, while C. hederifolium is the most available and hardiest fall flowering species (Table 1). Images of the different species show both the beautiful, dainty flowers and the wonderful leaf patterns that are available.

Table 1: Blooming times, native locations and hardiness of Cyclamen species.
Winter (December - March)
Species Native Area Tolerance to freezing
coum Bulgaria, Turkey and Lebanon extremely hardy
elegans north Iran, south shore Caspian Sea hardy
libanoticum Lebanon hardy in sheltered areas
persicum var. persicum eastern Mediterranean not hardy
pseudibericum Turkey hardy
repandum ssp. peloponnesiacum Peloponnesian Peninsula of southern Greece tender - hardy
trochopteranthm south Anatolia (Turkey) hardy
Spring (March - June)
balearicum Balearic Islands and southern France tender - hardy
creticum Crete tender - hardy
parviflorum northeast Turkey hardy
repandum southern Europe hardy
repandum ssp. peloponnesiacum Peloponnesian Peninsula of southern Greece tender – hardy
Summer - Autumn (July - November)
africanum north Africa not hardy
cilicium south Anatolia (Turkey) hardy
colchicum western Caucasus hardy
cyprium Cyprus tender - hardy
graecum mainland Greece & islands tender - hardy
hederifolium southern Europe (France to western Turkey) extremely hardy
intaminatum south Anatolia (Turkey) hardy
mirabile south Anatolia (Turkey) hardy
persicum var. autumnale Israel, south of Hebron not hardy
purpurascens south central Europe (France to Poland to Bulgaria) hardy
rohlfsianum north Africa not hardy
somalense eastern Somalia not hardy

Cyclamen are relatively long-lived plants, and so it is advisable to seed or plant them in the garden where you will disturb them the least. Remember to mark the spot well, so as not to dig where they are dormant and resting during the summer. Seedlings and young plants transplant easily any time, as long as care is taken not to damage the corm and the roots. If injured, a wound can be treated with fungicide such as garden sulfur, and then be left to dry for several days before replanting.

As a group, Cyclamen offer an almost endless variety of leaf colorations and patterns. I suggest, few gardens are large enough to hold them all. While the flowers may all seem to look alike except when examined closely, there are both color, scent and shape variations. These differences along with flowering time are used in identifying different species. Individual flowers can stay in bloom for more than eight weeks, especially with the early blooming kinds. When insects are not available for pollination, especially for species that bloom in the colder times of the year, Cyclamen can be self-pollinating. After a flower is fertilized, the flower stem starts to coil, placing the pod on the ground near the center of the plant. There, the seeds take all summer to ripen. If you want to collect the seed, keep an eye on these little coils, and when the seed capsule opens, be fast in collecting the seeds, or ants or wasps may carry the seeds throughout your garden. Ants carry the seeds away to eat the sugary coating off the seeds, without doing harm to the seeds, and so disperse them. New plants often sprout up along ant trails where the seeds are discarded! Seeds, even when taken from a selfed pod, will not yield uniform plants, and many leaf color variations can be expected.

Cyclamen coum
Cyclamen coum
Photo by Carla Bischoff

Bought or harvested seed should be sown as soon as possible, and covered with some five cm (two inches) of grit because they prefer to germinate in the dark. Planted seeds may take up to three years to germinate, so mark garden planting locations well, or if planted in pots, remove the germinated seeds, now small corms, each year when dormant for replanting, but keep the pots available so seeds that germinate in future years are not discarded. This pattern of germination is thought to better ensure seedling survival in locations where severe droughts periodically occur, as not all seedlings from a plant are then killed in any given severe drought year.

Cyclamen are mildly poisonous plants, and all parts of the plant are somewhat toxic. The underground corms, in their native locations, are only eaten by pigs and in the Pacific Northwest, very little pest damage is apparent throughout the year. Weevils will occasionally take a bite out of a leaf and their larvae may damage part of a corm, but usually Cyclamen take care of themselves. During the summer, slugs might attack some seedpods, but a bit of slug bait will quickly solve this. Leaves that have been damaged either by accident or frost might succumb to a fungus, but removing these damaged parts or dusting with garden sulfur will overcome this problem.

In summary, wouldn't it be a welcome surprise starting next winter to see some of these Mediterranean jewels beautifying your garden with scented flowers, and to know they will continue to do so for many years to come. Especially after a winter storm, nothing lifts a gardener's heart and spirit higher than to see these little garden amethysts glowing above a blanket of glistening fresh snow. No matter what your plans are, to buy plants or to just broadcast seeds at random in to your garden, you will be more than justly rewarded for your efforts with cyclamens.

Cyclamen hederifolium 
in the fall.
Cyclamen hederifolium in the fall.
Photo by Carla Bischoff

Some Selected Species Descriptions

C. hederifolium : the specific name makes reference to the shape and markings of an ivy leaf (hedera = ivy); it is the most easily grown hardy Cyclamen . It grows in sun or semi-shade and its flowers are produced from late summer to autumn just before the leaves, which have some of the most wonderful leaf patterns of this genus. This species grows over a wide range throughout southern Europe and the extreme western part of Asia Minor, from southeastern France to shores of the Black Sea, just north of the Bosporus, as well as from Sardinia to the northwestern part of Crete. It's a robust plant and needs at least a square foot of space to show its fullest splendor. It is also a very long-lived plant, and some tubers can reach a size of 0.5 kg (over a pound) and are thought to be in excess of 100 years old. Plants from seeds will start to bloom in their second year, and from then on the plants will steadily increase in size, with 50 or more blooms after just five to six years. The tubers need to be planted at least 8 cm (3 inches) below grade to assure support for the leaf and flower stems, which grow under-ground and side-ways away from the tuber for several 5-8 cm before showing above ground. The plant is dormant during July and August, but evergreen during the rest of the year. Depending on the genetics of the plant, flowers will show from late August on, with different varieties blooming over a three-month period. Flowers are held well above the plant and are elegantly shaped, with little bumps at the bottom of the petals. Colors can be white to very dark magenta. After flowering, the plant is an attractive ground cover. Grow this plant as a woodland plant under conifers, deciduous trees and bushes or as an accent plant in the open. Because it has sideways spreading roots (no roots on the bottom of the tuber), it can be easily grown in containers.

Fertilize these plants only lightly and keep them evenly moist during active growth. A slight sprinkle of ground oyster shell will benefit them.

Cyclamen hederifolium leaf
Cyclamen hederifolium leaf
Photo by Carla Bischoff

C. coum : This is one of the hardier species and one of the easiest to grow. It flowers from early winter and well into spring. It occurs from the mountains of Bulgaria south to Turkey and east into the Caucasus Mountains, including the Crimean Peninsula, usually in shady places. Leaf colors can be shiny green, silvery or have silvery-green zones in the leaves. The leaves are round to kidney shaped in the western end of its growing region and tend to become more pointed toward the east. Grow this plant in soil with good drainage with the tubers at least eight cm (three inches) below the surface of the soil. Flowers are held well above the plants, giving an excellent show at a time when there is little else in bloom. When in bloom, the plants can tolerate snow or frost without being damaged, and the flowers are just as erect when the snow has melted as they were before being covered with snow. The petals are somewhat propeller shaped and tend to extend to the side of the flower. There are white, pink and dark magenta colors available, and most flowers have a dark zone at the base of the petals. Because of the many clones available, it is difficult to predict what color the flowers of seedlings will be. They need very little fertilizer, but C. coum does prefer a slightly alkaline soil, which can be achieved with a light top-dressing of lime chips or crushed oyster shells (a teaspoon full per plant). Because they are rather small and low to the ground, do not grow these plants close to more vigorously growing plants. From July to the end of August these plants are dormant, and new leaves begin to show in early September, which will persist to the next summer.

Cyclamen coum
Cyclamen coum
Photo by Carla Bischoff

C. alpinum , syn. C. trochopteranthum , is a species in the C. coum group from southwestern Turkey where it grows in rocky areas, deciduous woodlands, and scrub. Flowers occur in spring and vary from pinkish carmine to white with a darker stain around the mouth. The petals are twisted, like a ship's propeller and the leaves are rounded or heartshaped with shallow toothing and silver green markings. This species will thrive in a sunny rock garden and may need some protection from competitors, as it is smaller than C. coum and can easily be overwhelmed by more vigorous rock garden plants. Plant this species in an area where it has room to grow at least a foot deep. Fertilize only lightly and reduce watering during late summer. It is dormant during mid summer and evergreen for the rest of the year. There are several flower colors available.

C. purpurascens : This is the only evergreen cyclamen species. It is native to mountain woods and rocky places in the most of the Alps, as far south as the southern foot-hills in northern Italy, and spans an area from south eastern France in the west to the southern most part of Poland and down into the northern Balkan States. Flowers appear from late summer to late autumn and are pale to deep carmine. Most are nicely scented, but it is not as easy to grow and flower as some of the other species. It benefits from being kept cool and not allowed to dry out in summer, being planted deeply, and being well mulched. The species is well adapted to grow under trees and bushes and will naturalize under rhododendrons.

This plant does not like root disturbance, and it is suggested to seed the plant where you want it to grow, as it is deep rooting. Plant seeds 10-15 cm (4-6 inches) deep and cover with some loose well-draining material. Allow about three years for all the seeds to germinate. The best place to grow C. purpurascens is in shaded areas, with definitely no midsummer afternoon sun. This species grows upward extensions from its growing areas on top of the tuber. These "floral-trunks" will elongate every year and should be covered with several inches of mulch if they show above grade. It appears that this is an adaptation to growing in a forested area where debris adds to the top of the soil every year. Because this is an evergreen species, it may add new leaves and shed older ones during all seasons. Keep evenly moist all year and fertilize only lightly.

Cyclamen purpurescens
Cyclamen purpurescens
Photo by Carla Bischoff

C. repandum : This is a species from southern Europe, where it grows from south eastern France across the Southern Alps to the coastal area of the Balkan States. It is one of the last cyclamen species to break dormancy in spring, sometimes not until March. The leaves are heart shaped with a narrow and deep sinus making them almost triangular, are angled and lobed and are often toothed. Many leaf forms and patterns are available. Flowers often appear with or soon after the leaves and are white to pale or deep pink, often with a pink or purplish red zone around the mouth, carmine magenta or reddish purple. Petals are sometimes twisted, and the flowers are held elegantly erect above the plant. Grow it as a woodland plant with good drainage and little fertilizer. Because these plants only show their presence for about four months per year, mark the spots where they grow to avoid later disturbing and damaging them.

Cyclamen repandum
Cyclamen repandum
Photo by Carla Bischoff

C. cilicium : This species comes from south eastern Turkey, where it grows as a woodland plant. It is not as hardy as either C. coum or C. hederifolium but will survive west-coast winters well. Should it lose its leaves during an exceptional cold winter, it will come back the following fall, and seeds set in the fall will ripen, even without leaves, during the following summer. This is a smallish plant, with leaves held erect and flowers presented well above the foliage. Flower colors range from pure white to pink and dark pink, and the white variety is thought to be the hardiest. This is a fall flowering species that gives color to a garden when most summer flowering plants have finished blooming. While it thrives in dappled shade, it will do equally well in a more exposed situation. Because of its size, it is also good in a rock garden if there is at least 15 cm (6 inches) downward space for the roots. Plant tubers some 10 cm (4 inches) below ground level. If left undisturbed, it will self seed in the area where it grows.

More information about these charming little garden plants can be obtained from the Cyclamen Society, and if you become members, as a bonus they will send you every year free seeds, where the value of the seeds just about equals the cost of the yearly membership. The Cyclamen Society web site is www.cyclamen.org

Bill Bischoff
Bill Bischoff and his wife Carla successfully grow and bloom 18 Cyclamen species as outdoor plants, and their garden, which also contains many hardy orchids, has received awards several times by the City of Surrey. They are members of the South Fraser ARS Chapter.