More good news about the Erica verticillata - April 2013.
The Rondevlei burn in March 2013.
The flowering shrubs at Rondevlei before the burn.
Here are some thoughts on what I observed at the ecological burn at Rondevlei – the fire behaviour in these plants was very different to what I have witnessed in these sort of fynbos systems before.
The fire being set. The heat is starting to build up.
What was significant about the ecological burn that I performed on the 27 March 2013, was that the stand of Erica verticillata (about 150 plants) allowed their leaves to burn off in a burst of flames, but then the bushes themselves would not burn up. This resulted in a stand of dead skeleton plants that had retained their seed capsules. These opened up the next day and started shaking out seeds as the wind shook the bushes. Usually in fynbos systems like this, with old dry bushes, one expects the fire to clear up the material, leaving perhaps only the largest parts of the plants behind. Often however fynbos fires remove all the matter, leaving the area devoid of plant matter. This can be particularly true for wetlands, where plant growth is higher and there is more plant matter to burn during fires.
The dark smoke gives one a clue of what is burning.
The intense fire is caused partially by the volitile oils in the plants leaves.
The fire cycle for the Cape Flats Sand Fynbos should be some 10 – 12 years, as a guideline.
Erica verticillata is a classic reseeder fynbos species; it produces masses of seeds during its short (>20 years) life cycle. It burns out during a fire and the next generation comes from the seed bank that has been laid down during its life.
The seed pods burnt. This sets off the
next process to distribute
Erica verticillata is a narrow endemic, growing in the seasonal edge of wetlands. Given its narrow distribution range and specific habitat type, it would appear to me that this species retards and absorbs the full impact of a fire, preventing its seed pods from burning off, while allowing the fire to clear out the plant growth underneath the plants to provide a niche for the next generation.
by Dalton Gibbs.
For plenty more background information
about Erica verticillata,
text supplied by Sandra Fowkes from the Veld and Flora magazine.
The Story of the Erica Verticillata. see a close up photo of the flower.
Erica verticillata is a handsome, strong growing, hardy erica averaging 1.5 m in height but at times growing up to 3 m tall. It produces beautiful mauve-pink, tubular flowers 15-20 mm long, near the ends of sturdy branches. The flowers, which are most attractive, are arranged in neat whorls that form impressive flower heads from January to March. The name ‘verticillatus’ means whorled and refers to the arrangement of the flowers and leaves.
Erica verticillata once grew in profusion on Cape Town’s ‘Cape flats’. Herbarium records indicate that it occurred in a narrow band between the main road and the M5 freeway from the Black River in the Mowbray and Rondebosch areas to as far as Zeekoeivlei near Muizenberg. It prefers seasonally damp, acid, sandy soils near rivers and drainage systems, but agricultural and urban development in the expanding City of Cape Town destroyed its habitat. This majestic Erica probably became extinct in the wild during the first half of the twentieth century. The last herbarium specimen collected from a naturally occurring population dates back to 1908. Later records of it in South Africa are herbarium specimens of a plant from Kirstenbosch Botanical Gardens in 1943, and a specimen submitted by J. E. Repton in 1961 from a cultivated plant growing in Pretoria at the Belvedere Palace.
Tracking down plants of Erica verticillata
There is some scepticism amongst conservationists about the value of keeping collections of wild species in botanical gardens (ex situ conservation). The happy ending of the Erica verticillata story is proof that growing wild species in botanical gardens or private collections can play an important role in preserving a species. Although Erica verticillata had not been seen for many decades and was thought to be extinct, Deon Kotze, a horticulturist specializing in ericas at Kirstenbosch, began a concerted search amongst the remnants of lowland fynbos near the Cape Peninsula for lost and rare Erica species in the early 1980s. He was particularly keen to find Erica verticillata, which looked so impressive on the herbarium sheets.
A few years later, a chance conversation between Deon and a Kirstenbosch scholar, David von Well led to a significant discovery when David mentioned that there was a large erica matching the description of Erica verticillata growing in Protea Park in Pretoria. Cuttings and flowering specimens were brought for Deon and Dr Ted Oliver, Erica specialist at the Compton Herbarium, who confirmed that is was indeed Erica verticillata. No records exist of how the plants came to be in Protea Park, but they were thought to have been introduced during the 1940s. Three plants once grew in the Park, but two had died by the 1980s. Cuttings were collected from the last remaining plant and introduced to Kirstenbosch in 1984. In the same year David Cooke, Temperate House Manager and Erica enthusiast at the Royal Botanic Gardens at Kew, heard about the rediscovery of Erica verticillata in Pretoria from Kirstenbosch horticulturists at the Chelsea Flower Show. He reported that Kew also had specimens of this species and kindly sent cuttings of their clone to Kirstenbosch with Graham Duncan, a Kirstenbosch horticulturist. Kew records show that they had a number of different forms of Erica verticillata, but unfortunately some had been discarded.
It is interesting that the form we received from Kew originates from seed sent to them in 1961 by Mr. Harry Wood, the curator of Fernkloof Botanical Garden. A few years later, in 1990, a large mature plant was discovered by Kirstenbosch Garden’s foreman, Adonis Adonis, growing in a clearing in the forest behind the Braille Trail at Kirstenbosch. It is surmised that this plant was a remnant seedling from the old Erica collections that were grown on terraces nearby. These three clones were successfully propagated from cuttings and established in the Kirstenbosch Garden collections. One might have thought that this was the end of a happy tale, but there is more… I wrote an article on Erica verticillata and asked Ted Oliver to check it. After reading the article, he said that he believed that there was a further clone, as he had seen plants in cultivation in a nursery attached to the Belvedere Palace Gardens in Vienna back in 1967!
He remembered that there was quite an impressive collection of southern hemisphere plants that were grown in containers so that they could be moved indoors each winter. Ted made contact with a fellow researcher, Dr Michael Kiehn, at the nearby University of Vienna and through their efforts we managed to get a fourth clone of this lovely species. As a bonus we found that they also had plants of Erica turgida, another Cape lowlands species that became extinct in the wild in the early 1970s when a housing development adjacent to Kenilworth Racecourse obliterated the last remaining population. The process of retrieving these two erica species proved most difficult with all the restrictions on importing plant material into South Africa. The back and forth communications between myself, Dr Kiehn and the Belvedere Garden attracted the attention of the Austrian Ministry of Agriculture and the South African Embassy in Vienna culminating in an official ceremony where the Austrian Minister of Agriculture and the Environment, Dr Wilhelm Molterer, handed the plants over to the South African ambassador Professor Alfred T. Moleah.
A history of the Ericas from Vienna
When at last all the red tape had been cut through and I eventually took possession of the valuable erica package, I was surprised to find two separate packs of Erica verticillata cuttings, one labelled ‘red’ and the other ‘pink’. This was most intriguing, as the plants have only been propagated vegetatively (from cuttings) in all the decades that they have grown them and should therefore be identical. I contacted the horticulturist at the Belvedere Palace Garden, Mr Michael Knaak, who confirmed that they have two forms of Erica verticillata in their collections, a lax growing form (our cover photo) and a light pink form. They have no records of the origin of the plants and could only give me verbal information handed down from generation to generation. Between 1786 and 1799, two gardeners at the Belvedere Palace Garden, Francis Boos and George Scholl, set off on an expedition to collect plants for Joseph II, Emperor of Austria. Francis Boos was evidently the leader as he was well educated, spoke several languages and was a botanist as well as a gardener, whereas Scholl was a working gardener with little scientific knowledge.
Joseph II had sent them to make collections of tropical plants from Mauritius, but bad weather forced their ship to shelter at the Cape of Good Hope and their stay was longer than planned. They made numerous collections of South African plants and even went on a brief collecting trip with Francis Masson. Boos then went on to Mauritius leaving Scholl behind to continue collecting, returning to the Cape in 1788 for a few months before returning to Vienna in July 1788 with a large collection of specimens and living plants. Scholl stayed at the Cape for twelve years, mainly because he could not get passage on a ship that would transport his plant collections. Scholl was assisted by Colonel Robert Jacob Gordon who gave him protection, assisted him with his field excursions and allowed him to grow his plants in his garden, often referred to in the literature as ‘the Gordon’s Garden’. Many plants were established here and Scholl collected seed from these plants. From time to time Scholl sent shipments of dried bulbs and seeds to Vienna of which four shipments are recorded in the CapeArchives from 1790 to 1792.
They were shipped to the Austrian Consul in Holland who forwarded them upriver and overland to Vienna. He finally returned to Vienna in 1799 with his large collection of living plants and seed that included Erica species. Dr Kiehn and the staff at Schönbrunn Botanical Gardens believe that the ericas at the Belvedere Palace Garden date back to the Boos and Scholl collections as there is no evidence of any other collections being made. Ted Oliver remembers that when fellow Erica specialist, Hans Dulfer, spoke to an old gardener at Belvedere, he said that the South African ericas had been in the collection since he started working there in the 1930s. His predecessor remembered them always being there too, so we may surmise that the Erica collections at Belvedere date at least as far back as the nineteenth century and therefore quite conceivably originate from the Boos and Scholl collections.
When I visited Vienna in 2005 I saw at least twenty Cape ericas in the Belvedere collections including Erica patersonii, E. cerinthoides, E. turgida, E. mollis, E. ventricosa, E. heleophila, E. canaliculata, E. diaphana and E. baueri. It is incredible to think that many of these collections may have been nurtured for over 200 years through all the political turmoil of wars and conquest. The Belvedere Palace and Schönbrunn Palace Gardens were severely damaged by bombing at the end of the Second World War, and I asked Michael Knaak how the plants could have survived. His enquiries revealed that most of the plants were indeed destroyed at the end of the war when bombs destroyed glasshouses at Schönbrunn and Belvedere. however, many collections survived because they were purposely duplicated and kept in other gardens and glasshouses. The Erica collection was taken to the Alpengarten (Alpine Garden) where there is an ‘Erdhaus’ or glasshouse built below ground so it is free from frost even when the artificial heating systems are not functioning. This is apparently how the Erica collection survived the last winter of the Second World War.
If the two surviving forms of Erica verticillata are directly descended from these collections this proves that, given the right techniques and dedicated horticulturists, rare species can be preserved for long periods away from their natural habitats. This is a comforting thought since the pressure on natural habitats has increased dramatically in the last 100 years.
Return to the wild
All the natural habitats of Erica verticillata, with the exception of Rondevlei and Kenilworth Racecourse, have been destroyed by development. Dalton Gibbs, Conservation Manager for the Cape Metropolitan Council, re-introduced the ‘Pretoria’ clone of Erica verticillata to Rondevlei Nature Reserve in 1994 with limited success. He planted ten plants across a range of habitats, but only one plant survived in an area between the dry and wet soils. More plants were established at a second, similar site over the next few years, and they have grown well. They attract nectar seekers and pollinators such as the lesser double-collared sunbird, hawk moths and bumblebees and are producing viable seed to replenish the seed banks that ensure the plants’ survival after the vegetation is burnt. Healthy fynbos habitats require periodic fire to clear senescent (old) plant material and stimulate regeneration from seed. In 2001 the Kirstenbosch clones of Erica verticillata and Erica turgida were also planted in the reserve.
The search for a lost Erica has resulted in the discovery of five distinct forms of Erica verticillata, but also developed into restoration projects and an on-going exercise in detective work. The assistance of Botanical Gardens, the British Heather Society and the Internet has revealed the existence of a number of other Erica verticillata forms and hybrids from collections at Tresco Botanical Gardens, a nursery in Germany, a nursery in California and a few from the British Heather Society. Trying to determine the origin and genetic integrity of these forms is difficult because plants are often exchanged between organizations without good documentation. It is therefore possible that we may have received duplicate collections from different sources or hybrids. The next step is to have the plants sequenced in the molecular laboratory at Kirstenbosch to establish whether they are unique clones from different wild collections or not. This will help establish the size of the genetic pool and verify their status as true species. Initial molecular investigation indicates that we have five distinct clones or forms of Erica verticillata, but three of these appear to be sterile. This work will be fundamental to the implementation of restoration projects.
The conservation of our rich Cape flora is a great challenge, especially with the increased demand for land and resources, and climate change. This is particularly true on the lowlands where Erica verticillata originates. Many other species will not be so lucky and will be lost forever. An example is Erica pyramidalis, which grew together with Erica verticillata, but is now extinct in the wild and has no ex situ cultivated plants. Erica verticillata can play a crucial role in the conservation of the threatened lowlands flora, as it has become a flagship species that creates awareness and symbolizes the plight of our vanishing flora. You can help by planting some of these threatened plants in your gardens, joining the Botanical Society and becoming involved in community based conservation projects like the Custodians of Rare and Endangered Wildflowers (CREW).
Hitchcock, A. 2006. Restoration conservation at Kirstenbosch Veld & Flora 92 (1), 40 - 43.