Some seek novelty or just plain inspiration from the world's public gardens. Others are interested in the culinary or medicinal qualities of plants. Whatever the reason, people have always had a deep fascination with flowers, seeds and greenery. So what got us into this in the first place?
These are a few explanations from recent times.
The Garden of World Medicine in London's Chelsea
Medication has advanced enormously since 1758 when a clergyman in Chipping Norton, England, experienced pain relief while chewing on a willow twig. Six decades later Italian chemists extracted the same active ingredient from a herb called meadowsweet. French research and German modification followed and in 1900 Bayer patented aspirin.
Back in England, apothecaries at Chelsea Physic Garden were also studying the medicinal properties of plants and an international botany exchange has operated there since the 1700s. More recently, renewed interest in plant-based medicine led to the establishment of a Garden of World Medicine. It illustrates how various ethnic groups use plants for medicinal purposes. There is also a new Pharmaceutical Garden featuring plants which are the origins of contemporary drugs. Edible and Useful Plant Gardens have recently been completed.
Aside from that, Chelsea Physic Garden is a very pleasant retreat. Groupings of flowers and shrubs familiarise the visitor with many famous people who were associated with the garden. These include Carl Linnaeus, the Swede who devised the Linnaean System of classifying plants, William Hudson, who first applied the method to British flora, and Sir Joseph Banks, who donated seeds collected on his voyage to Australia. Banks also donated basaltic lava brought back from a voyage to Iceland.
With stones from the Tower of London, this was used in the construction of England's first pond rock garden. It is heritage listed and worth a look for its novelty value.
The Chelsea Physic Garden is open to the general public from April to October and to Friends of the Garden year-round.
Herb City, South Korea
During the Joseon Dynasty era, Yeongnam-daero Street in Daegu City formed part of the main road connecting Korea from north to south. As a major traffic route it was always filled with people and their products, in particular oriental medicinal herbs. Their ongoing relevance accounts for Daegu City's current position as the only area in Korea to be designated as a special district of herb medicine.
Reliving traditions dating back at least 350 years, the Daegu Yangnyeongsi Herb Medicine Festival takes place in Daegu City every year during May. It began as a major event in the opening ceremonies of the Daegu Medicinal Herb Fair, which first took place in 1658 and developed into an important international distribution hub with links through all of Asia and as far afield as England, Russia and Germany.
Today the action takes place downtown in Namseongno, Jung-gu, where the wholesalers, pharmacies, clinics and ginseng stores encapsulate oriental medicine traditions. Ginseng is the most popular herb, credited as beneficial for just about everything, so chicken and ginseng soup restaurants are also abundant. Close by is the Oriental Medicine Cultural Centre and the Yangnyeongsi Herb Garden, which showcases various medicinal herbs in a charming and restful environment less than two hours by train from Seoul.
Italian and Japanese Gardens in Ireland
For those who like their gardens to be formal and grand in scale, Powerscourt House, south of Dublin in County Wicklow, presents 19 hectares of showpiece gardens commissioned by the Wingfield family during their 350-year occupation of the Powerscourt estate.
The Walled Gardens are among the oldest remaining features. These are famous for their rose beds and a herbaceous border with 250 varieties of flowers and shrubs. A flamboyant remodelling in the 1730s brought Powerscourt's grounds into the wider Wicklow landscape through the creation of a broad tree-lined avenue and formal tree plantings that framed the vista from the house.
Inspired by the aristocratic gardens of Europe, an ornamental lake and terraced Italianate gardens were later commissioned. Statues, ironwork and decorative garden features in marble and bronze complete these works. Finally, in 1908, following Oriental trends, a Japanese Garden with a pagoda, stone lanterns and bridges over a stream was added as a backdrop for imported azaleas, Japanese maples and Chinese Fortune Palms.
Orchids in Singapore
Carl Linnaeus's scientific classification system set the plant world in order and these works inspired plant enthusiasts to travel abroad and collect. More than that, Linnaeus and other botanists realised that plants possess sexual organs.
If the pollen of one species succeeds in fertilizing another, hybrid offspring are produced. This offered new and exciting possibilities.
In his publications, Linnaeus described orchids at considerable length. These are perhaps the most exotic - some might say erotic - plants on earth and hard-nosed collectors can become intoxicated with their beauty.
Even ordinary members of the gardening public have been known to develop such a passion to possess more and more orchids that it teeters towards obsession. It is known as orchidelirium.
The world's biggest collection of tropical orchids is held by the Singapore Botanic Gardens.
Orchids have been associated with these gardens since 1859 and there has been a breeding program since 1928.
The result is a sprawling collection of more than 1000 species and some 2000 hybrids. Of these, 600 species and hybrids are permanently on display.
Lilies under glass at Kew
Hand in hand with a desire to possess rare plants, the interchange of imported specimens grew, greatly aided by the invention of glass greenhouses which facilitate the cultivation of plants from tropical climates. The zeal of the Victorian collector knew no bounds. The same goes for the curiosity of the general public.
One of the most popular exhibits under glass at London's Kew Gardens is the giant water lily, a highly-prized ornamental native to tropical South America where it grows all year round in the lakes and backwaters of the Amazon.
In a natural environment, beetles pollinate the water lily. The fragrance of its flowers attracts the beetles, the lily's petals close, trapping the beetles inside its core until, finally, they are released, covered in the pollen which they then spread to other flowers.
At Kew the giant water lily is hand-pollinated. In a cool climate the breeding program is more complex with plants grown behind the scenes in a Tropical Nursery where they are raised from seed as an annual. The best specimens are moved to Waterlily House and the Princess of Wales Conservatory where the public can view them in summer. The 1995 display created a record with leaves exceeding 2.5m in diameter, placing Kew and its giant water lily in the Guinness Book of Records.
The Garden of World Medicine shows how ethnic groups use plants for medicinal purposes.