But perhaps the chief attractions here are the short, informative nature trails that allow the visitor to experience for themselves a ‘museum of living plants’ and their associated stories. The Boyce Thompson Arboretum epitomises the joy of gardening with desert plants, providing living proof that, when it comes to succulent gardens, the plants will still be around and fit for duty long after their original cultivators have gone.
Agave murpheyi (left) is one of the most commonly encountered species of Agave in the Sonoran Desert. After flowering, this medium-sized, rosulate leaf succulent forms a multitude of bulbils on the inflorescence (centre), which can reach a height of eight metres. This Agave murpheyi mother plant has died (right), but the survival of the clone is ensured through the production of basal sprouts. Many species of Agave were, and are still, important sources of food, beverages and medicines in their native areas. The bulbils formed on flower stalks, or basal suckers (also called pups), of many of these species are easy to transport and re-establish in a new site.
Moods can be both made and influenced by design. From afar, the reds and oranges of aloe flowers invite passers-by to visit the Arboretum. The red flowers belong to a hybrid between Aloe claviflora and Aloe grandidentata, while the bicoloured candles of Aloe camperi, a native of Ethiopia and Eritrea, are visible in the left-hand middle ground.
Desert plants produce some of the most spectacularly coloured flowers. Psorothamnus schottii, the indigo bush, has intensely deep blue flowers (top), while Encelia farinosa, the brittle-bush, has bright yellow flowers (above). Although invasive in many parts of the world, under desert conditions Nerium oleander provides useful and dense colour as a shrubby tree. It is commonly known as oleander, from its superficial resemblance to the olive tree, Olea spp., to which it is not related. ALOES IN BLOOM As the chill of winter approaches, one can confidently look forward to a pleasant and perky display of colour in a succulent
garden, because this is when aloes come into bloom. Most people spend more time indoors in winter but, for succulent lovers, the vibrant, candle-like blooms of aloes draw them outdoors to admire these lovely plants. Gardens overrun with exuberant succulents and succulent companions invariably have an abundance of tension on the surface. Texture is brought to life in this way. The leaves of the small Agave toumeyana subsp. toumeyana are beautifully adorned with white marginal threads and the surfaces carry the impressions of the central bud leaves.
The Mexican Agave salmiana var. salmiana can grow to the size of a small family car, making it a very useful specimen plant for large gardens. It grows well in desert climates and in mild conditions.
Agave victoriae-reginae is a popular indoor and greenhouse succulent in places very remote from its native Mexican habitat; this magnificent specimen looks very much at home here in the desert environment of the Arboretum.
The saguaro (Carnegiea gigantea) is an engineering marvel in every respect. The fluted trunks and branches consist of an internal framework of ‘rods’ – the plumbing system of the plants, here clearly visible in this dead specimen – around which the water storage pulp is carried.
The most common shrub of North American deserts is Larrea tridentata, the creosote bush. This yellow-flowered, bushy shrub carries its flowers in spring, but rain can stimulate it to flower at other times of the year. The creosote smell in these deserts after rain comes from its leaves, which have a foul taste and, as a result, are never grazed by domestic livestock.
Three species of the cactus genus Mammillaria grow well in desert conditions. With their abundance of flowers, they provide colour to the beds in which are they are established. M. compressa subsp. compressa (above right), commonly known as mother-of-hundreds, is a highly proliferous, eyecatching species. Although it grows as low, multi-headed mounds, its tubercles bear long, white spines that almost entirely obscure the plant bodies, especially during times of drought. Its flowers are a beautiful reddish pink, while the fruits of the similarly shaped M. carnea are deep red (top right). The stems of the cliff-dwelling Mammillaria matudae (left) grow vertically downward; its flowers are luminescent pink and are mostly concentrated in concentric rings near the tips of the stems.
Carnegiea gigantea, the saguaro (pronounced ‘sa-WAH-ro’) certainly is the most recognisable of the Sonoran Desert plants. These stately trees grow very slowly and usually only flower after about 30 years, when the plants are about 1.5m tall. Trees may be expected to produce their first branches after about 70 years. The tough skin of the saguaro’s body is light green, with a waxy appearance. The trumpet-shaped flowers are pure white.
A trilogy of companions growing in harmony. In the foreground is Agave americana var. americana with its blue-grey leaves, with the static, columnar Neobuxbaumia polylopha, commonly known as the Aztec column, growing behind it. The tree in the background, with its complementary dark green foliage, is the Mexican (Chihuahuan Desert) Pithecellobium flexicaule (widely known as Ebenopsis ebano), a slow-growing, but strikingly beautiful, evergreen shade tree for arid areas.
Yucca valida, with its dagger-shaped leaves adorned with marginal threads, towers over a garden bed.
The Boyce Thompson Arboretum has a number of very large, thriving specimens of Echinocactus grusonii, the golden barrel cactus. Originating in Mexico, this is one of the most widely cultivated cacti in the world. The fiercely armed, concertina-like ribs of the barrel-shaped plant body allow it to expand when moisture is absorbed. (In Afrikaans, this cactus is called skoonma-se-kussing or mother-in-law’s cushion!)
A hybrid between Aloe claviflora and Aloe grandidentata grows in abundance at the Boyce Thompson Arboretum. Its soft red flowers brighten up the otherwise drab, yellowed spring landscape.
You can introduce a pop of red colour into a dry corner of the garden by planting succulents, such as this low, hardy and easy-to-grow aloe. A selection of this hybrid has been named Aloe ×commutata. Close-up of an inflorescence of Aloe ×commutata. The flower clusters of one parent, Aloe grandidentata, are not as dense as those of the hybrid. FACT BOX
ADDRESS: Boyce Thompson Arboretum, 37615 US Highway 60, Superior, Arizona, USA. CONTACT: Recorded information: +01 (520) 689-2811; office: +01 (520) 689-2723. OPENING HOURS: Summer (May–Aug) 06:00–15:00; Winter (Sept–Apr) 08:00–17:00. Closed Dec 25. BEST TIME TO VISIT: Year-round; summer can be very hot. COST: Entrance fee charged. ATTRACTIONS: Sonoran Desert Exhibit, Chihuahuan Desert Exhibit, Cactus Garden, South American Exhibit, Australian Exhibit, Herb Garden, Eucalyptus Forest, HummingbirdButterfly Garden, Demonstration Garden, Children’s Garden, Ayer Lake, Queen Creek. Over 270 bird species. Guided nature walks and independent walking trails: Main Trail (2.5 km), High Trail (0.5 km). FACILITIES: Visitor Centre, plant sales, gift and snack shop, picnic sites, dogs on leashes. ACCESSIBILITY: Most exhibits and part of the Main Trail are accessible for wheelchairs. INFORMATION: http://azstateparks.com/parks/both/index.html
Symmetry and balance add casual elegance to any garden. In the Desert Botanical Garden, this is achieved through juxtaposing the structure of the entrance with the woven appearance of the canopies and the branches of the palo verde trees.
Facilities include a fountain at the visitor entrance, situated beneath an entrance arbour constructed from rusted metal. The hill in the background (one of the buttes of Papago Salado) falls within the boundaries of the Garden. The cylindrical cactus in the left foreground is Ferocactus cylindraceus. When viewed in broad sweeps, the natural desert vegetation around Phoenix, in Arizona, the Grand Canyon State, bears an uncanny resemblance to that encountered in rural Karoo towns like Steytlerville, Wolwefontein and Jansenville. The vegetation can essentially be described as a low-growing, sparse shrubland interspersed with small trees, agaves and cacti (aloes and euphorbias in the case of the Eastern Cape). But this is where the superficial similarity ends. The city of Phoenix – named for the mythical bird – was established in 1867 and today is a thriving metropolis. There are not many cities in the world where succulents make up the majority of plants used to embellish sidewalks, verges and street medians, but in Phoenix, an array of succulents have been utilised in both recreational and civic horticulture. In this arid southwestern city, large trees of Carnegiea gigantea, the saguaro, together with other cactus and succulent species, are encountered where they have been planted along roadsides. Phoenix is situated more or less in the centre of Arizona, at an elevation of 350m above sea level. It has a mild desert climate, averaging about 300
sunny days per year; the rainfall is so low that very few outdoor activities get rained out. A request to establish the Desert Botanical Garden was first put forward in 1937. The state land set aside for the Garden covered about 60 hectares (145 acres) and was situated 15 km (9 miles) east of Phoenix, within the boundaries of Papago Park. The Papago Salado region – an island of remaining natural desert where the cities of Phoenix, Scottsdale and Tempe meet – is set among dramatic red sandstone rock formations, called buttes (pronounced ‘beauts’). The request to establish the Garden was very much driven by conservation concerns – unusual for the 1930s. At the time, a group of local residents, notably Mrs Gertrude Divine Webster, were alarmed by the rapid transformation of desert plant life as a consequence of agriculture, mining and urban expansion. DENSE PLANTINGS A clever way to renew a tired succulent bed or border is by turning to traditional, thick, planting patterns. Dense cheek-byjowl planting creates an emphatically modern look, while the closely established plants help to give a garden a sense of effortless ease.
Stem succulents from the Old and New Worlds: here, a euphorbia (on top of the pillar) and a cactus grow happily side by side in pots.
The saguaro, Carnegiea gigantea, can reach a height of nearly 20 metres and can live for a few hundred years. Woodpeckers make holes in the stems and create neat little hollows in which to raise their brood. When they evacuate these nests, elf owls or cactus wrens take up residence. This particular specimen has a crest of abnormal growth – a phenomenon known as fasciation. There is a widespread misconception that deserts are lifeless stretches of nothingness. In reality, the Sonoran Desert that surrounds Phoenix is home to nearly 2500 plant species which, in turn, support abundant animal life, all of which is very much in need of conservation. The Desert Botanical Garden is well positioned under a few buttes (hillocks). It has clusters of invitingly shady trees that beckon from the parking area and surround the visitor centre. Overall, the Garden seems to be more natural landscape than formal design, yet it contains several perfectly proportioned structures, and the beds have been laid out in classical style. But, of course, the backdrop to much of the developments remains the starkly beautiful, saguaro-dotted desert landscape. Within this simplicity are swathes of indigenous cacti and sparsely branched, broadcrowned trees, particularly the palo verde (Parkinsonia spp.). This sparselyleaved tree suffuses sunlight by day, allowing plants to thrive in the dappled shade beneath.
Although the initial living collection of the Desert Botanical Garden consisted of just 659 specimens, over the past eight decades it has grown to well over 20,000 individual plants, representing some 4000 different species of cacti, succulents, trees, shrubs and wild flowers. Today, the Garden is home to one of the world’s largest and most diverse collections of desert plants, with the added bonus that they are displayed against an amazingly beautiful natural desert landscape, where curiously spiny plants project skywards from a rigid granite floor, which is covered in indigenous Sonoran Desert plants. The Garden continues to actively expand its horizons as it renews and reengineers its commitment to local, national and international stakeholders. Developments over the past decade include a terraced spiral (planted en masse with giant Agave weberi and the smaller Agave desmettiana as a ground cover), a fountain at the visitor entrance, pleasantly scenic courtyards, and several new buildings, including a garden shop and a functions facility that can accommodate hundreds of delegates. The buildings include the Webster Auditorium, one of the few remaining examples of Pueblo Revival architecture in central Arizona. In addition to the laboratories and the cultivated beds of the living research collections, the Garden also boasts a large area of natural ‘borrowed’ landscape dotted with cactus trees, notably Carnegiea gigantea, and desert shrubbery. Waterwise gardening is well-established in Phoenix. As early as the 1980s, this environmentally friendly way of gardening with water-thrifty indigenous and other plants was popular in most parts of the US Southwest as an increasing demand on water resources for domestic use became evident. In this desert city, those water-guzzling ‘green deserts’ (otherwise known as lawns) are, thankfully, not a common sight in domestic gardens. With its dense masses of luminescent yellow flowers, borne in spring, the small to medium-sized blue palo verde tree (Cercidium floridum), is strikingly beautiful. Here, where shade trees – indeed any trees – are valued treasures, palo verde trees stand out as true gifts to desert landscaping. The blue palo verde is a particularly fast-growing indigenous tree that reaches a height of 12m and provides reasonable shade. It is usually multi-stemmed, but in domestic gardens it can be trained into anything from one to several main trunks. The stems and branches are a yellowish green, not unlike those
of the African fever tree (Acacia xanthophloea), and the uninitiated can be forgiven for initially confusing these two species from a distance. Early views of the Agave spiral on a terrace near the visitor entrance. Large, chunky specimens, such as Agave weberi, effectively ‘ground’ this garden scheme. The spiral is planted en masse with giant blue-leaved agave, with the much smaller A. desmettiana used as a ground cover. Part of the garden shop is visible in the background. Another species that lights up the desert in early spring is Larrea tridentata, one of the most common shrubs of the Sonoran Desert. This aromatic species, commonly known as creosote bush or grease wood, is not
the source of the commercial product creosote, but is so named because it yields a very distinctive scent to the desert after a fall of rain. The decorative rusted iron gateway leading to the Desert Botanical Garden creates a simple frame and adds texture and rich brown tones to the entrance. Although visitors tend to focus on the beds and formal collections, it is the incorporation of the borrowed landscape that sets this Garden apart and helps to enhance the visitor experience. Ferocactus cylindraceus subsp. cylindraceus (also widely known as Ferocactus acanthodes) is one of the most striking barrel cacti of the Sonoran Desert. Although it starts its life as a small, ballshaped plant, it can grow in columnar fashion to over 3m tall. The ribbed trunk is a feature shared with many barrel cacti.
The flowers are a bright yellowish orange colour and borne in a ring at the stem tips. The spines vary in colour from red through yellow and brown to grey. This cultivated specimen of Agave cerulata subsp. subcerulata from Baja California Sur, in Mexico, is very much at home in the harsh Arizona environment. The original plant has died, but its sideshoots are now growing in a ring around its remains.
The ocotillo, Fouquieria splendens subsp. splendens, is a multi-stemmed, formidably spiny plant that carries leaves only in wet weather. At the onset of a dry period it sheds its leaves, leaving just spinelike leaf stalks. A plant may react like this repeatedly during a single season. It bears clusters of beautiful crimson red, cylindrical aloe-like blossoms throughout spring and early summer.
WHAT DEFINES ‘CONTEMPORARY’ GARDENING AND LANDSCAPING PRACTICES IN DESERT REGIONS? The answer becomes clear when visiting the Desert Botanical Garden: minimalist combinations of drought-tolerant plants, the vibrant greens of the towering stems and foliage of succulents and cacti, and brightly coloured flowers dotted throughout – all silhouetted against a backdrop of crisp blue skies and low, undulating hills bathed in bright sunlight. Situated on the periphery of greater Phoenix, the Garden is strictly a xeriscape – in fact, only waterwise, drought-resistant plants will thrive in this desert environment, with many regular garden plants simply surviving, or just barely hanging on.
With its dense masses of bright yellow flowers that are borne in spring, the strikingly beautiful Cercidium floridum (blue palo verde) is a valued landscaping treasure for desert gardens. This particularly fast-growing, multi-stemmed native tree is planted around the visitor facilities.
A wall of colour. In nature, the bright purple-red flowers of Bougainvillea glabra are best when the plants get little supplemental irrigation. Horticulturally, the species often performs better if subjected to dry or desert-like conditions. Close-up of the flowers of Agave ocahui var. longifolia, a densely flowered species. The flowers of this agave are not carried singly, but in small clusters of a few flowers.
DESERTS: ARID PARADISES In Arizona, the landscape is generally referred to as ‘desert’; in South Africa, the vegetation of the central arid parts is commonly called ‘karoo’. This name, which is of Khoekhoe origin, means ‘land of thirst’ and is usually variously prefixed, as in Little Karoo or Worcester-Robertson Karoo, to indicate relative size or geographical location. In everyday communication, South Africans reserve the term ‘desert’ for the arid, sandy wastelands of the Namib and the Kalahari. Perhaps, because so much of South Africa is desert-like, the use of this descriptive word is reserved for those areas that are really, really very arid and apparently devoid of plant, animal and human life.
The scarlet red visual feast that consists of red hot spires belongs to Aloe arborescens.
Arizona is cactus country. The chain-fruit cholla (pronounced ‘CHAW-yuh’), Cylindropuntia (Opuntia) fulgida, is a particularly nasty customer as far as cacti are concerned, as its fruits or densely thorny stem segments can easily attach themselves to unsuspecting passers-by. The spines are barbed and very quickly become firmly attached to human skin or animal fur. Its fruit bears fruit, so to speak, forming long chains that eventually become dislodged from the mother plant. These chains of fruit then set root where they drop and grow new plants.
The beds around the visitor facilities have been planted with water-thrifty species and the surface of most beds is covered with an inorganic mulch of decomposed rock. The leafless, wiry stems of Pedilanthus macrocarpus (slipper plant) remain erect and give an austere, rather formal feel to the softscaping around the symmetrical lines of the buildings.
Gardeners in climatically milder parts of the world will be more familiar with the zigzag, succulent stems and white-mottled leaves of P. tithymaloides subsp. smallii (Jacob’s ladder or slipper plant), which is often planted as an accent plant or trained into a low hedge. (EF) This Agave bovicornuta, commonly known as Lechuguilla verde or cow’s horn agave, has come to the end of its life. This species does not form suckers, so the next generation will have to be propagated from seed. A medium to large plant with bright yellowish green leaves, its true attraction lies in its leaf marginal armature, which resembles miniature cow’s horns.
As part of the threatened species programme conducted by the Desert Botanical Garden, specimens of the miniature Agave parviflora are grown in pots kept under glass. STRUCTURE AND COLOUR: TWO SIDES OF THE COIN A visually pleasing, well-designed garden should incorporate both structure and colour. In a predominantly succulent garden, structure can be imparted by using architectural plants that are long-lived and have bold forms, such as the various largegrowing species of agave (century plants), aloes, cacti, yuccas and tree euphorbias (milkweeds). Colour, particularly flower colour, tends to be seasonal. Most species flower in a particular season and for the rest of the year they grow vegetatively, building up resources for the next season’s flowering event. It is therefore advisable to plan colour carefully, taking account of which species will flower when. Take aloes for example. Regardless of where they are grown in the world, they mostly
produce their flowering cones and candles in winter so, in an aloe garden, you need to include summer-flowering species. Several Kniphofia species, the red-hot pokers, flower in summer, and during these hot months their densely flowered inflorescences readily substitute for those of aloes. Although variegated leaves are encountered fairly frequently among species of Agave, particularly in the Agave americana complex, this is a very rare specimen of a strikingly variegated Agave murpheyi. The spiny shrub in the background is the ocotillo (Fouquieria splendens subsp. splendens).
Dasylirion wheeleri, the desert spoon or sotol (pronounced ‘SOH-tole’), has narrow, ribbon-like, sharply toothed grey-green leaves that radiate from the apex of the trunk to form a large, near-perfect, fluffy-looking sphere. This species is very drought tolerant and can survive on as little as 270mm annual rainfall, without supplemental irrigation.
Aloe camperi, which originates from East Africa, thrives in Arizona’s desert climate. Here, in the Desert Botanical Garden, it provides colour during the summer months when few other aloes flower. FACT BOX ADDRESS: Desert Botanical Garden: 1201 N. Galvin Parkway, Phoenix, Arizona 85008, USA. OPENING HOURS: May–Sept: 07:00–20:00; Oct–Apr: 08:00– 20:00. Closed 4 July, 25 Dec, Thanksgiving. BEST TIME TO VISIT: Year-round. The milder temperatures of spring and autumn give respite from the heat of summer and the cold of winter. COST: Entrance fee charged. Free on second Tuesday of month from 13:00–20:00. ATTRACTIONS: Cactaceae and Agavaceae collections (designated in June 2010 as The National Collections of
Cactaceae and Agavaceae by the American Public Gardens Association); plant sales in March and November. FACILITIES: Patio Café; Garden shop; extensive programme of walks, talks, garden tours, events and exhibitions; free wi-fi in selected areas; sunset concert series. No pets; no picnics. ACCESSIBILITY: Parking on site; 15-minute walk from nearest bus stop. INFORMATION: http://www.dbg.org
Succulents of all shapes, sizes and textures have been planted around this white-leaved variegated Agave sisalana.
In this corner of the Desert Garden, the beds are framed by Yucca elephantipes (on the right) and Y. filifera (background on the left). Planting a variety of succulents and then applying a bit of patience can result in a similar magical transformation in any garden. CROWDED HOUSE With succulents, there is no such thing as overplanting. Densely establishing plants is not necessarily a bad thing, as most species seem to benefit from the root competition. And, if above-ground growth becomes too dense, plants can be easily thinned out. This is better than having to wait for several seasons for plants to attain their mature dimensions. A marketing phrase widely used by South African tourism authorities – ‘a world in one country’ – also applies to California, which can confidently claim that it is ‘a world in one state’. Heavily populated, southern California in general, and the greater Los Angeles Basin in particular, is an immense, congested grid crisscrossed by a network of interstate highways, and dotted with towns and cities that have virtually flowed together.
In general, southern California has a decidedly Mediterranean climate, receiving precipitation mainly in winter and experiencing dry, hot summers, with temperatures that can soar to near 40°C. In Los Angeles and other metropolitan areas, the lush, green gardens are the result of extensive yearround irrigation, since this semi-desert region has a fairly low rainfall, averaging ±250mm per year. Hot Santa Ana winds (the equivalent of South Africa’s berg winds) that sweep from the Mojave and other inland deserts over the coastal mountains and down the canyons (valleys) are an environmental hazard that gardeners here have to deal with. Santa Anas can blow at up to 160 km per hour, desiccating vegetation in their wake. However, the combination of drying winds and a mild climate makes southern California ideal for cultivating succulent species. At the Huntington Desert Garden, both an under-cover potted succulent collection and an open-air collection are accessible to the public.
Yucca elephantipes grows as a multi-stemmed giant if given space and the right climate. The ‘Mediterranean climate’ parts of California lie to the west of the Sierra Nevada and other north-south aligned mountain ranges. The plant communities in this winter rainfall region can be broadly grouped as chaparral, coastal scrub, oak woodland and redwood forest. Chaparral consists largely of tough, leathery-leaved shrubs and tends to be rather impenetrable, which is why cowboys wear protective chaps (a word derived from the Spanish chaparro, from which chaparral is in turn derived) when traversing this vegetation type on horseback.
On the wide, open plains of southern California, south of Los Angeles, which are dotted with low scrub, Agave deserti subsp. deserti flourishes in the intense desert climate, where rainfall is scarce and midsummer temperatures frequently top 40°C.
The Anza-Borrego Desert State Park, the largest in California, is situated about 160 km from San Diego. This rugged desert wilderness is a popular getaway spot for hikers and off-roaders but, thankfully, it retains its unspoilt simplicity. It has been claimed that anything will grow in southern California as long as it is watered. Succulents are no exception, and species from all over the world appreciate the prevalent warm summer heat and mild, wet winters. Over the years, numerous ‘alien’ shrubs, trees, annuals and ground covers have become so at home in this part of the State that many are now firmly established as part of the introduced flora. Sadly, some of these have become invasive, threatening the native Californian plants. The Huntington, a private, non-profit institution, is a world class cultural, research and educational centre that incorporates The Huntington Art Gallery, an internationally renowned art collection, The Huntington Library and Press, as well as a number of botanical gardens. It owes its origins to Henry E. Huntington (1850–1927), a business magnate who made his fortune in the Southern Pacific Railroad Company and real estate investments in southern California. In 1903, he purchased San Marino Ranch, a 240-hectare (600-acre) property that included citrus groves, nut
and fruit orchards, cereal crops and livestock. Working with horticulturalist and landscaper, William Hertrich, Henry Huntington set about developing the large gardens. This included obtaining large and showy plant specimens from local nurseries and plant collectors, and the property soon became a botanical laboratory for new introductions from all over the southwestern USA. Today, at least 14,000 species are cultivated on the estate. In nature, plants do not grow in straight regimented rows; this planting of very old specimens of Echinocactus grusonii surrounding a specimen of Agave parryi shows how haphazard placement can contribute to the visual appeal of the bed. (EF) San Marino, a quiet, upmarket city with shady, tree-lined streets, is situated south of Pasadena. One of the first parts of Los Angeles to be settled, Pasadena has retained much of its old-California charm. ‘Pasadena’ means ‘crown of the valley’ and the area was so named by the Chippewa Indians. Located in the San Gabriel Valley, the city is overlooked by the majestic 3000m-high San Gabriel mountains. Pasadena is the home of Caltech (California Institute of Technology), a small independent university that has become one of the world’s leading research centres, with 32 Nobel Prizes having been garnered by its faculty and alumni. The Huntington Botanical Gardens comprise a series of interlinked gardens, including a Rose Garden, Chinese Garden, lily ponds, Shakespeare Garden, and Conservatory for tropical plants. The estate covers 83 hectares
(207 acres), of which 48 hectares (120 acres) are landscaped and open to visitors. The individual gardens are edged with trees and shrubs of varying height and texture and separated by paths, terraces and lawns. Each garden has its own character, yet they form a seamless unit, thanks to the opulent nature of the planting and the immaculate upkeep of the estate by a team of gardeners, curators and volunteers. The Desert Garden was established in 1907. Within a year, the first collecting expedition was undertaken to the deserts of New Mexico, Texas and Arizona, and south to Mexico. But the species on display are not limited to New World succulents. Over the years, material has been added from southern Africa, the Canary Islands, Madagascar and other succulentrich regions. Today the Desert Garden covers four hectares (10 acres) and features over 5000 succulent species in 60 landscaped beds, making it one of the largest and best-known outdoor aggregations of mature succulents in the world. Because the Garden has been planted to please the senses rather than reflect a particular plant classification system, species from different geographical regions are placed alongside each other. Here, tree-like aloes, such as Aloe barberae, and yuccas, such as Yucca filifera, grow side by side, giving parts of the Garden an almost forest-like appearance.