Clivias By Paula Szilard “Clivias are undeniably aristocrats of horticulture. They are classed among the most desirable of all connoisseur plants offering not only spectacular flowers, but also interesting variations in both leaf variegation and plant form.” Professor Harold Koopowitz Author of the seminal work on clivias, 2002 Clivia miniata Named after Lady Charlotte Florentia Clive, Duchess of Northumberland, at whose conservatory they first bloomed, clivias were discovered in 1815 by the naturalist and explorer William Burchell in the forests of Eastern Cape Province of South Africa. Additional plants were collected in the same area in the early 1820’s by the plant collector and Kew gardener James Bowie. It was Bowie’s plants that Lady Clive succeeded in flowering and that botanists used to classify and name clivias. In 1828, by some quirk of fate, this plant was simultaneously named by two leading British botanists in separately published articles, William Jackson Hooker and James Lindley, a botanist at Kew gardens. Hooker’s name didn’t stick, but Lindley’s ‘Clivia nobilis,’ did. Lindley wrote, “We have named this genus in compliment to her grace, the Duchess of Northumberland, to whom we are greatly indebted for an opportunity of publishing it. Such a compliment has long been due to the noble family of Clive, and we are proud in having the honour of being the first to pay it.” That is why, the name is most commonly pronounced as “clyvia” rather than rhyming with trivia. This was my first excursion into the world of the clivias. I have only grown them since 2008. I had long coveted the orange miniatas I had seen at my local garden center. Then a friend gave me one and I was smitten. I found another beautiful, large specimen at an estate sale for $4.00, about a tenth of what you pay for a large plant. Both were root bound and were transplanted immediately, but nonetheless bloomed in late December and early January. I now have collected all of the species except C. mirabilis, which has been difficult to come by. When I visited South Africa in 2010 I was delighted to see clivias in the wild, at botanical gardens and even at a flower show. The Species The genus Clivia consists of six evergreen species in the Amaryllidaceae family. Some are relatively easy to tell apart. With others, the distinctions are more subtle and it helps to have botanical training and use a key. Please note that although the open-faced trumpet shaped C. miniata is what most of us know as a clivia, five of the six species have pendant, tubular flowers. The flowers of all species in the genus are borne on umbels, similar to Queen Anne’s Lace. 1. C. caulescens. This is a species with narrow pendant tube-shaped orange to cream flowers with green edging very similar to those of C. nobilis. It was discovered in Limpopo Province in the northern part of South Africa in the 1890’s, but was not described until 1943, the first clivia species to be described in its native land. It is the only clivia with real stems, which can to 6 feet tall. It also has the distinction of being the species most tolerant of sun and is accustomed to the hot, wet summers and cool, dry winters of its native habitat, with an occasional light frost at higher elevations. 2. C. gardenii. Native to the Kwa Zulu-Natal Province, C. gardenii was named after Major Robert C. Garden, the British plant explorer who found it. It has pendant peachy-orange flowers edged with green. A natural variant with white to yellow flowers has also been found. C. gardenii is a sizeable plant, with leaves measuring over two feet long. 3. C. mirabilis. Amazingly, this clivia, the newest species in the genus, was not discovered in Northern Cape Province until 2001. Its flowers are more distinctive than those of other pendulous flowered species. It has drooping red/orange flowers and dark red pedicels (flower stems). The flowers sometimes have greenish yellow edging. This plant requires less water than other clivias 4. C. miniata. This is the plant we all knows as Clivia. It has orange, red or yellow trumpet shaped often flattened flowers that put on a very striking display when they bloom. Native to the Eastern Cape, Kwa Zulu Natal and Swaziland, it is probably the most commonly found clivia in southern Africa. It is also the most frequently hybridized clivia and the plant we commonly have in our homes and see in garden centers. In the northern hemisphere it blooms in the winter, most often in December or early in the year. This species has different natural forms. In addition to the orange or red flowers, often with a yellow center, there is a yellow variant, C. miniata, var. citrina and a nearly white flowered plant with touches of pink, called ‘Appleblossom.” “Chubb’s Peach is a naturally occurring peachy yellow variant. 5. C. nobilis. The actual species named after Lady Clive and the type species for this genus, this plant has pendant, curved tube shaped orange flowers, but they are tipped in yellow and green. It is found only in the Eastern Cape, mostly along the coastline. Seedlings in this species are extremely slow growers, usually taking more than 5-6 years from seed to bloom. I got mine when it was supposedly near blooming size, but after four years, it is only about 2 feet tall and it still has not bloomed. In nature, this species grows about 1 ½ - 3 feet tall 6. C. robusta. This plant passed for C. gardenii until 2004 when it was classified as its own species. It looks quite similar to C. gardenii: pendant, curved dark to pale orange flowers with green tips. The leaves can be quite long, some measuring over 3 feet. Like others clivias, it has a naturally occurring yellow form: C. robusta, var. citrina. Its natural habitat is in swampy terrain in the coastal forested areas of northern Eastern Cape and southern Kwa Zulu Natal, so it can handle poorly draining soils while other clivias can’t, but it also does well in well–drained soils. Hybridization The Clivia Society in South Africa is the name and registration authority for new cultivars. Its Clivia Register and Checklist describes well over 1000 hybrids. Many of these are intraspecific (within a species), but interspecific (between species) hybrids of C. miniata have gained ground. Understandably, South Africa has the distinction of producing many of the new hybrids. Historically, there was a substantial amount of breeding and growing of C. miniata in Europe. Currently Belgium is the leader in production. Germany, France and the Netherlands also produce large numbers of plants. California has emerged as the locus of hybridization activity in the United States, no doubt because of its mild climate, yet there are growers in other parts of the country, including Colorado. The focus of American breeding has been on colorful flowers and to a lesser extent on variegated foliage. China and Japan are also known for their contributions to breeding. Clivia nobilis was likely the first species introduced into Japan around 1850, followed by C. miniata in the 1870’s. The Japanese have excelled at breeding miniature or dwarf hybrids with beautiful short, wide leaves, often variegated. They were much less focused on the flowers than Western breeders. Then during World War II during the occupation of China Japanese officials brought their clivias with them and left them behind when they withdrew. The Chinese were taken with these plants and started to hybridize them. During the Cultural Revolution in the 1960’s and 1970’s, many unique plants were destroyed, but the industry recovered. Now the breeding of clivias is a multi-million dollar industry. Like the Japanese, the Chinese focus on the leaves. Clivias are often thought of as Victorian plants, however, they were not widely grown as houseplants during that time. Because of their high cost, these plants available chiefly to the well-to-do. As late as 1890, clivias were still not found in a standard plant reference book of the period. If they had been popular, they would have been discussed there. Surprisingly, clivias are still expensive today. A large specimen of Clivia miniata will cost anywhere between $40-50, probably because the plants are slow growers, especially if started from seed. Because there are now such a large number of cultivars, let’s focus on the ones that are more commonly available. There are some interesting miniatas, especially in pink and peach or bronze. There are a number of yellow cultivars in addition to the natural variant C miniata, var. citrina: C. miniata ‘Aurea,’ and C. miniata ‘Golden Dragon,’ as well as a peachy yellow called ‘Victorian Peach.’ ‘Fire Lily’ is another attractive red cultivar of C. miniata. All have been at various times available from Logee’s. The cyrtanthiflora hybrids are interspecific crosses of C. miniata and C. nobilis. They have pendant blossoms that are much more open than those of C. nobilis. These delicate flowers exist in various shades of orange, peach and apricot. Clivia Care When grown outdoors, clivias thrive in subtropical or Medierranean climates. For those of us in the colder temperate zones, clivias make perfect, long lived houseplants because they like shade and are good indoor bloomers. They are attractive even when they aren’t blooming because they have lovely dark green strap shaped leaves, some of which are stacked in two tidy piles like gasterias. They are quite tolerant of our dry interiors in the winter, but do not locate them too close to a heating vent. They are capable of surviving a lot of abuse, but they cannot tolerate being over watered. If you are known for a heavy hand with the watering can, you can compensate by adding more sand, scoria, etc to you potting mix. Still, it’s wise to test the humidity before you pour During spring and summer move your clivias outdoors into light, but not deep shade. Too much sun can scorch the leaves. Water generously and fertilize your clivias once a month, but DO let the surface dry out between waterings. Use a slow release or an all purpose fertilizer with an NPK ratio of roughly 20-20-20, and make sure it has all the micronutrients as well. Also, during this time the plant likes warm temperatures. Although books advise you never to let Clivias dry out completely, you do need to reduce watering considerably and expose the plant to lower temperatures in the fall and early winter to bring it into bloom. This is sometimes referred to as an early winter rest period, lasting for 6-8 weeks. During this time, give your clivias temperatures below 50 F, but definitely a few degrees above freezing. Leave them outdoors until the first frost threatens. Then put them in an unheated porch or bedroom. The books say that when plants don’t get enough chilling time, they may not flower and if they do, the flower stalks may remain short and stay “stuck” between the leaves. When I got my plants, I was unaware of this requirement. In the case of my estate sale plant it should already have been chilled before I got it, but apparently it wasn’t. It was located in the dining room at its previous home. My flowers, though still beautiful, were indeed “scrunched” between leaf blades. Immature plants, which are not at the blooming stage, do not need this rest period at cooler temperatures. Place your plants at a window that gets bright light with early morning or late afternoon sun. If you locate it facing west, you may need to move them back from the window. Water generously in the spring and summer. Pot up your plants in a porous, well draining peat-based mix such as Fafard no. 2. For small containers add a little sand, scoria or fine gravel to the mix. For containers larger than 5 gallons, use the proportions 2/3 mix to 1/3 sand or any of the above to make the mix more porous. Plants can go along time without being repotted, on average of three to four years. In fact, they seem to bloom better when pot bound. The pot you transplant into should be only slightly larger than the root ball. Drilling additional drainage holes or enlarging the existing drainage hole will allow for better drainage. Clivias have thick, fleshy roots for water storage with a corky absorbent layer of velamen, similar to what is found on orchid roots. This is thought to help the plants absorb water and nutrients. Topdressing in years when they are not being transplanted is advisable. Scrape away about 2 inches of the mix, being careful not to damage the root system and replace it with fresh mix to which you have added a little bonemeal and some slow-release fertilizer. Repotting and top dressing are best done in the late winter. After clivias bloom, remove the seed heads unless you’re planning start more plants from seed. They will consume too much of the plant’s energy and it may not flower in the next bloom cycle. When the cut flower stems turn brown, they are easily pulled out. Propagation Propagate your plants by removing the offsets. This is far easier said than done. Offsets should have at least three leaves before they are removed from the mother plant. You must first find where the offset is attached to the parent and cut it with a sharp knife. Then comes the hard part …. untangling the roots and freeing the offset. The best time to do this is when the plant has finished blooming. Plant the offsets in a 5” clay pots, using a mixture of peat-based potting mix and coarse sand. If you are young enough and very patient, you can propagate plants from seed. Although some growers have grown plants from seed to flowering in 30-36 months, it could take most of us at least 5 years (depending on the species or variety) to get from seed to flowering. Pests Apart from mealy bugs, I have not had any pests or disease problems. The Clivia Society website lists mealy bugs, aphids, red spider mites, thrips and whiteflies as potential insect pests. If you do have any such infestations, you will probably not want expose yourself to the vast arsenal of agricultural chemicals to remedy the situation, especially not in your home. If the infestation is small, you may want to consider strong jets of water or soap sprays for aphids and mealy bugs. In case that does not work for you, sprays of ultra fine horticultural oil mixed with water will usually do the trick. The oil and water spray is also effective for spider mites, thrips and possibly whiteflies, but hopefully, you will never have to deal with those. Keep in mind that all these pests are difficult to eradicate and plants will require several treatments. Also, testing the oil spray on an inconspicuous part of the plant is always a good idea. Clivias are extremely rewarding plants and bloom reliably in the home. They have lovely, arching symmetrical leaves and are attractive even when they are not blooming. They just need a little special attention at certain times of the year and are certainly worth the effort because they bring a cheery brightness to your living spaces when you most need it, in the short, drab days of winter. Books: Duncan, Graham. Grow Clivias: A Guide to the Species, Selected Hybrids, Cultivation and Propagation of Clivias. 2nd ed. Kirstenbosch, S.A.: South African National Biodiversity Institute, 2008. 188 p. Koopowitz, Harold. Clivias. Portland, OR: Timber Press, 2002. 384 p. Swanevelder, Dirk and Roger Fisher. Clivia: Nature and Nurture. Praetoria, S.A.: Briza Publications, 2009. 220 p. Van der Merwe, Lena et al. Cultivation of Clivias. 2nd ed. Praetoria, S.A: Clivia Society, 2007. 71 p. Websites: www.cliviasociety.org www.northamericancliviasociety.org (has links to American growers)

Clivias

Paula Szilard

“Clivias are undeniably aristocrats of horticulture. They are classed among the most desirable of all connoisseur plants offering not only spectacular flowers, but also interesting variations in both leaf variegation and plant form.”

Professor Harold Koopowitz

Author of the seminal work on clivias, 2002

Clivia miniata

Named after Lady Charlotte Florentia Clive, Duchess of Northumberland, at whose conservatory they first bloomed, clivias were discovered in 1815 by the naturalist and explorer William Burchell in the forests of Eastern Cape Province of South Africa. Additional plants were collected in the same area in the early 1820’s by the plant collector and Kew gardener James Bowie. It was Bowie’s plants that Lady Clive succeeded in flowering and that botanists used to classify and name clivias.

In 1828, by some quirk of fate, this plant was simultaneously named by two leading British botanists in separately published articles, William Jackson Hooker and James Lindley, a botanist at Kew gardens. Hooker’s name didn’t stick, but Lindley’s ‘Clivia nobilis,’ did. Lindley wrote, “We have named this genus in compliment to her grace, the Duchess of Northumberland, to whom we are greatly indebted for an opportunity of publishing it. Such a compliment has long been due to the noble family of Clive, and we are proud in having the honour of being the first to pay it.” That is why, the name is most commonly pronounced as “clyvia” rather than rhyming with trivia.

This was my first excursion into the world of the clivias. I have only grown them since 2008. I had long coveted the orange miniatas I had seen at my local garden center. Then a friend gave me one and I was smitten. I found another beautiful, large specimen at an estate sale for $4.00, about a tenth of what you pay for a large plant. Both were root bound and were transplanted immediately, but nonetheless bloomed in late December and early January. I now have collected all of the species except C. mirabilis, which has been difficult to come by. When I visited South Africa in 2010 I was delighted to see clivias in the wild, at botanical gardens and even at a flower show.

The Species

The genus Clivia consists of six evergreen species in the Amaryllidaceae family. Some are relatively easy to tell apart. With others, the distinctions are more subtle and it helps to have botanical training and use a key. Please note that although the open-faced trumpet shaped C. miniata is what most of us know as a clivia, five of the six species have pendant, tubular flowers. The flowers of all species in the genus are borne on umbels, similar to Queen Anne’s Lace.

1.C. caulescens. This is a species with narrow pendant tube-shaped orange to cream flowers with green edging very similar to those of C. nobilis. It was discovered in Limpopo Province in the northern part of South Africa in the 1890’s, but was not described until 1943, the first clivia species to be described in its native land. It is the only clivia with real stems, which can to 6 feet tall. It also has the distinction of being the species most tolerant of sun and is accustomed to the hot, wet summers and cool, dry winters of its native habitat, with an occasional light frost at higher elevations.

2.C. gardenii. Native to the Kwa Zulu-Natal Province, C. gardenii was named after Major Robert C. Garden, the British plant explorer who found it. It has pendant peachy-orange flowers edged with green. A natural variant with white to yellow flowers has also been found. C. gardenii is a sizeable plant, with leaves measuring over two feet long.

3.C. mirabilis. Amazingly, this clivia, the newest species in the genus, was not discovered in Northern Cape Province until 2001. Its flowers are more distinctive than those of other pendulous flowered species. It has drooping red/orange flowers and dark red pedicels (flower stems). The flowers sometimes have greenish yellow edging. This plant requires less water than other clivias

4.C. miniata. This is the plant we all knows as Clivia. It has orange, red or yellow trumpet shaped often flattened flowers that put on a very striking display when they bloom. Native to the Eastern Cape, Kwa Zulu Natal and Swaziland, it is probably the most commonly found clivia in southern Africa. It is also the most frequently hybridized clivia and the plant we commonly have in our homes and see in garden centers. In the northern hemisphere it blooms in the winter, most often in December or early in the year. This species has different natural forms. In addition to the orange or red flowers, often with a yellow center, there is a yellow variant, C. miniata, var. citrina and a nearly white flowered plant with touches of pink, called ‘Appleblossom.” “Chubb’s Peach is a naturally occurring peachy yellow variant.

5.C. nobilis. The actual species named after Lady Clive and the type species for this genus, this plant has pendant, curved tube shaped orange flowers, but they are tipped in yellow and green. It is found only in the Eastern Cape, mostly along the coastline. Seedlings in this species are extremely slow growers, usually taking more than 5-6 years from seed to bloom. I got mine when it was supposedly near blooming size, but after four years, it is only about 2 feet tall and it still has not bloomed. In nature, this species grows about 1 ½ - 3 feet tall

6.C. robusta. This plant passed for C. gardenii until 2004 when it was classified as its own species. It looks quite similar to C. gardenii: pendant, curved dark to pale orange flowers with green tips. The leaves can be quite long, some measuring over 3 feet. Like others clivias, it has a naturally occurring yellow form: C. robusta, var. citrina. Its natural habitat is in swampy terrain in the coastal forested areas of northern Eastern Cape and southern Kwa Zulu Natal, so it can handle poorly draining soils while other clivias can’t, but it also does well in well–drained soils.

Hybridization

The Clivia Society in South Africa is the name and registration authority for new cultivars. Its Clivia Register and Checklist describes well over 1000 hybrids. Many of these are intraspecific (within a species), but interspecific (between species) hybrids of C. miniata have gained ground. Understandably, South Africa has the distinction of producing many of the new hybrids. Historically, there was a substantial amount of breeding and growing of C. miniata in Europe. Currently Belgium is the leader in production. Germany, France and the Netherlands also produce large numbers of plants.

California has emerged as the locus of hybridization activity in the United States, no doubt because of its mild climate, yet there are growers in other parts of the country, including Colorado. The focus of American breeding has been on colorful flowers and to a lesser extent on variegated foliage.

China and Japan are also known for their contributions to breeding. Clivia nobilis was likely the first species introduced into Japan around 1850, followed by C. miniata in the 1870’s. The Japanese have excelled at breeding miniature or dwarf hybrids with beautiful short, wide leaves, often variegated. They were much less focused on the flowers than Western breeders. Then during World War II during the occupation of China Japanese officials brought their clivias with them and left them behind when they withdrew. The Chinese were taken with these plants and started to hybridize them. During the Cultural Revolution in the 1960’s and 1970’s, many unique plants were destroyed, but the industry recovered. Now the breeding of clivias is a multi-million dollar industry. Like the Japanese, the Chinese focus on the leaves.

Clivias are often thought of as Victorian plants, however, they were not widely grown as houseplants during that time. Because of their high cost, these plants available chiefly to the well-to-do. As late as 1890, clivias were still not found in a standard plant reference book of the period. If they had been popular, they would have been discussed there. Surprisingly, clivias are still expensive today. A large specimen of Clivia miniata will cost anywhere between $40-50, probably because the plants are slow growers, especially if started from seed.

Because there are now such a large number of cultivars, let’s focus on the ones that are more commonly available. There are some interesting miniatas, especially in pink and peach or bronze. There are a number of yellow cultivars in addition to the natural variant C miniata, var. citrina: C. miniata ‘Aurea,’ and C. miniata ‘Golden Dragon,’ as well as a peachy yellow called ‘Victorian Peach.’ ‘Fire Lily’ is another attractive red cultivar of C. miniata. All have been at various times available from Logee’s.

The cyrtanthiflora hybrids are interspecific crosses of C. miniata and C. nobilis. They have pendant blossoms that are much more open than those of C. nobilis. These delicate flowers exist in various shades of orange, peach and apricot.

Clivia Care

When grown outdoors, clivias thrive in subtropical or Medierranean climates. For those of us in the colder temperate zones, clivias make perfect, long lived houseplants because they like shade and are good indoor bloomers. They are attractive even when they aren’t blooming because they have lovely dark green strap shaped leaves, some of which are stacked in two tidy piles like gasterias.

They are quite tolerant of our dry interiors in the winter, but do not locate them too close to a heating vent. They are capable of surviving a lot of abuse, but they cannot tolerate being over watered. If you are known for a heavy hand with the watering can, you can compensate by adding more sand, scoria, etc to you potting mix. Still, it’s wise to test the humidity before you pour

During spring and summer move your clivias outdoors into light, but not deep shade. Too much sun can scorch the leaves. Water generously and fertilize your clivias once a month, but DO let the surface dry out between waterings. Use a slow release or an all purpose fertilizer with an NPK ratio of roughly 20-20-20, and make sure it has all the micronutrients as well. Also, during this time the plant likes warm temperatures. Although books advise you never to let Clivias dry out completely, you do need to reduce watering considerably and expose the plant to lower temperatures in the fall and early winter to bring it into bloom. This is sometimes referred to as an early winter rest period, lasting for 6-8 weeks. During this time, give your clivias temperatures below 50 F, but definitely a few degrees above freezing. Leave them outdoors until the first frost threatens. Then put them in an unheated porch or bedroom. The books say that when plants don’t get enough chilling time, they may not flower and if they do, the flower stalks may remain short and stay “stuck” between the leaves.

When I got my plants, I was unaware of this requirement. In the case of my estate sale plant it should already have been chilled before I got it, but apparently it wasn’t. It was located in the dining room at its previous home. My flowers, though still beautiful, were indeed “scrunched” between leaf blades. Immature plants, which are not at the blooming stage, do not need this rest period at cooler temperatures.

Place your plants at a window that gets bright light with early morning or late afternoon sun. If you locate it facing west, you may need to move them back from the window. Water generously in the spring and summer. Pot up your plants in a porous, well draining peat-based mix such as Fafard no. 2. For small containers add a little sand, scoria or fine gravel to the mix. For containers larger than 5 gallons, use the proportions 2/3 mix to 1/3 sand or any of the above to make the mix more porous.

Plants can go along time without being repotted, on average of three to four years. In fact, they seem to bloom better when pot bound. The pot you transplant into should be only slightly larger than the root ball. Drilling additional drainage holes or enlarging the existing drainage hole will allow for better drainage. Clivias have thick, fleshy roots for water storage with a corky absorbent layer of velamen, similar to what is found on orchid roots. This is thought to help the plants absorb water and nutrients. Topdressing in years when they are not being transplanted is advisable. Scrape away about 2 inches of the mix, being careful not to damage the root system and replace it with fresh mix to which you have added a little bonemeal and some slow-release fertilizer. Repotting and top dressing are best done in the late winter.

After clivias bloom, remove the seed heads unless you’re planning start more plants from seed. They will consume too much of the plant’s energy and it may not flower in the next bloom cycle. When the cut flower stems turn brown, they are easily pulled out.

Propagation

Propagate your plants by removing the offsets. This is far easier said than done. Offsets should have at least three leaves before they are removed from the mother plant. You must first find where the offset is attached to the parent and cut it with a sharp knife. Then comes the hard part …. untangling the roots and freeing the offset. The best time to do this is when the plant has finished blooming. Plant the offsets in a 5” clay pots, using a mixture of peat-based potting mix and coarse sand. If you are young enough and very patient, you can propagate plants from seed. Although some growers have grown plants from seed to flowering in 30-36 months, it could take most of us at least 5 years (depending on the species or variety) to get from seed to flowering.

Pests

Apart from mealy bugs, I have not had any pests or disease problems. The Clivia Society website lists mealy bugs, aphids, red spider mites, thrips and whiteflies as potential insect pests. If you do have any such infestations, you will probably not want expose yourself to the vast arsenal of agricultural chemicals to remedy the situation, especially not in your home. If the infestation is small, you may want to consider strong jets of water or soap sprays for aphids and mealy bugs. In case that does not work for you, sprays of ultra fine horticultural oil mixed with water will usually do the trick. The oil and water spray is also effective for spider mites, thrips and possibly whiteflies, but hopefully, you will never have to deal with those. Keep in mind that all these pests are difficult to eradicate and plants will require several treatments. Also, testing the oil spray on an inconspicuous part of the plant is always a good idea.

Clivias are extremely rewarding plants and bloom reliably in the home. They have lovely, arching symmetrical leaves and are attractive even when they are not blooming. They just need a little special attention at certain times of the year and are certainly worth the effort because they bring a cheery brightness to your living spaces when you most need it, in the short, drab days of winter.

Books:

Duncan, Graham. Grow Clivias: A Guide to the Species, Selected Hybrids, Cultivation and Propagation of Clivias. 2nd ed. Kirstenbosch, S.A.: South African National Biodiversity Institute, 2008. 188 p.

Koopowitz, Harold. Clivias. Portland, OR: Timber Press, 2002. 384 p.

Swanevelder, Dirk and Roger Fisher. Clivia: Nature and Nurture. Praetoria, S.A.: Briza Publications, 2009. 220 p.

Van der Merwe, Lena et al. Cultivation of Clivias. 2nd ed. Praetoria, S.A:

Clivia Society, 2007. 71 p.

Websites:

www.cliviasociety.org

www.northamericancliviasociety.org (has links to American growers)