Visited on September 24, 2007
Although the weather was generally good for most of our travels, the day trip to Edinburgh was extremely wet. We took a bus ride from the city centre to the Royal Botanic Garden of Edinburgh, the second oldest Botanic Garden in Britain. Founded in 1670 by two physicians who wanted to grow medicinal plants, the original garden plot was the size of a tennis court. Local physicians raised money for the importation of foreign plants for the garden. The gardens final relocation was in 1820 where, at the time of our visit, 70 acres provided room for Scottish Heath, Peat and Woodland, Rock, Chinese, Alpine Gardens, Arboretum and Glasshouses.
During the period of 1905-1932, over 10,000 plant specimens were introduced to the RBG of Edinburgh by the Scottish plant hunter, George Forrester, who made eight trips to Tibet and North-West China on behalf of the RBG garden and other private groups. New plants introduced at that time, included rhododendrons, primulas, magnolias, gentians, meconopsis and lilies. Now, in the 21st century, the RBG of Edinburgh and it’s 3 other botanical sites in Scotland, holds the 2nd richest collection of plant species in the world.
Botanic gardens, such as Edinburgh, serve a different purpose from other types of gardens that grow plants for purely aesthetic reasons. The RBG at Edinburgh is a scientific institution, dedicated to exploring, explaining and documenting the world of plants. They actively collect seeds (for seed banks) and or vegetative cuttings in the wild for their propagation nursery, for conservation purposes. Climate and environmental changes in relationship to plant life is researched at the RBG. Education is offered for all ages from visitors to horticulture and research students.
Due to the rain, our tour to the RBG was limited to the 10 linked glass houses. The climate in each house was regulated by computer control and replicated the temperature and humidity of the plants in their native habitat. The Temperate Palm House, built in 1858, served as the entrance to a wide variety of tropical plants that serve many purposes in our global economy, from food sources to medicinal uses. With over 2400 different plant species on display, I can only give an example of a few of these plants. Additional photos can be found in the photo archives of my website that you can access from the left sidebar.
In the Orchid and Cycad House, with humidity at 85% and the temperature at 74 degrees F, the tropical Screw Pine tree, native to Madagascar, had Dr. Seus looking brace roots, which provided anchorage for this tree that grows in swamps and unstable riversides. This tree is multi purpose as it’s poles and branches have been used in the construction of houses. In Hawaii the fruit, leaves, male flowers and roots are used in traditional medicines, to treat colds, flu and cancer.
Spanish Moss, an epiphytes plant with a gothic appearance, grows from North Landing State Park in Virginia Beach, Virginia to Argentina. It has a long history of use. In the 1600’s, colonist used it in construction as a binder in plaster, cement and caulking. In the early 1950’s it was used as an estrogen substitute. Scientist found that it exhibits antibacterial properties. Drugs extracted from it have been used in the treatment of diabetes, heart disease, edema and hemorrhoids. Studies have been made for a way to use it to control blood glucose levels. The Native Americans called the plant “tree hair” and the Spaniards named it “Spanish Beard.”
The Cycad family was represented by Encephalartos ferox, from the coastal areas of northeastern South Africa and Mozambique. These cycads have rigid, spiny leaflets and the cones of the male and female plants, (borne on seperate plants), can be bright orange, red or yellow. The Afrikaans name for this cycad is “broodboom,” which means bread tree. In the past, the natives would use the stem of the plant as a food source by fermenting the starchy pitch in animal skin and grounding it into a meal. This plant has become so popular in landscape use and as garden sculpture, a number of species are threatened in their native habitat due to over collection. Currently all species are protected by laws and any trade of these plants are subject to approval by the Nature Conservation, and international trade is strictly controlled. The Encephalartos ferox is still a relatively common species but it is dependent on protection in nature reserves.
The Cycas revolute or commonly known as Sago Palm, is the most widely planted cycad in the world. This Jurassic Period plant has existed for 300 million years and now is facing possible extinction in its native sub-tropical habitat of the Southern Island of Japan. A few of these slow growing cycads in this glass house are over 200 years old. In their own habitat, they can survive up to 2000 years.
The Plant and People House, with the highest humidity of the glass houses at 95%, and temperature at 76 degrees F, was an example of tropical rainforest vegetation. The prominent display was the central pond with Victoria Water Lilies. The genus name was given in honor of Queen Victoria of Great Britain. Native to the shallow waters of the Amazon, the large round floating leaves can reach six feet long with a rib structure supporting up to 50 pounds in weight. The flowers, with blooms 12” across, can change color and sex overnight. Native South Americans would grind water lily seeds to use as flour for cakes. At the Botanic Garden, which is far north and low level winter lights, the lilies can not be sustained all year round. Fresh seeds are sowed each January to produces new plants.
A display, called the Food Stall, showed examples of plants from the tropical rainforest that were important to the global economy as food sources and for medicinal uses. The rainforest provide the majority of the worlds 200 key plant foods.
A chill was felt when entering the Fern and Fossil House with 52 degree F temperature and humidity of 50%. Dinosaur footprints led around a pathway of cold hardy tree ferns from Australia, which can reach 70 feet in height. In contrast, the Golden Tree Fern, native of New Zealand, only grows to 13 feet in height and has a ”skirt” of old fronds around its fibrous trunk. The dinosaur footprints were a reminder that ferns, horsetails and club mosses dominated the Earth’s vegetation for 200 million years before flowering plants developed.
A walk through the Arid Lands was welcome warmth with 75 degrees F and humidity of 40%. Plants from arid regions have less the 20” of rain annually. Plants such as Agava and Aloe have fleshy leaves for water storage. Cactus leaves are spines as an adaptation to reduce water loss. The regions represented were North America, southern Africa, Arabia and Madagascar.
The Wet Tropic House, with the same warmth as the Arid Lands but an increase in humidity to 80%, provided an environment for plants of the Gesneriaceae family. These fuzzy leaved plants with attractive flowers, serve as under story vegetation, world wide, in the tropical rain forest. Also in this humid environment, native to Brazil, were many varieties the beautiful leafed Calathea species. These plants, which are water-loving plants, grow on the jungle floor by streams. The small pastel flowers they produce are insignificant compared to the striking patterns of their variegated leaves with markings of red, purple, and silver, with multiple shades of green on their leaves. A nearby waterfall was an indication of the humidity and water requirements these plants needed.
The Rainforest Riches House, with humidity at 80%, showcased plants from the moist forests of tropical America. Many of these plants were familiar as houseplants in cooler climates, as their minimum temperature is 65 degrees. The Dieffenbachias with toxic leaves, Bromeliad with its bright spiked flower, Codiaeum with variegated leaves in many bright colors and the Ficus tree, are popular for indoor displays. A Spatiphyllum can grow up to 5’ in height with leaves over 3’ in length in the tropics. As a smaller container plant it has become favored in homes and offices, since studies have indicated that it has health benefits in being able to remove indoor pollutants.
Indoor visits of botanical glass houses, with their collections of tropical plants that provide food, medicine or display beauty, can give a new perspective and appreciation of plant life throughout the world. The Royal Botanic Garden of Edinburgh’s wide collection of plants from warm temperate and tropical regions, with natural habitat of humidity, temperature, light and soil duplicated, is an insight of the diversity of plant life and the important role these plants play in our society.
Visit this site at: www.rbge.org.uk