Striking colour contrasts are created by combining the yellow-spined Echinocactus grusonii (golden barrel or mother-in-law’s cushion) with the smaller, white-spined, pincushion-like Mammillaria geminispina, set here against a backdrop of red and black lava rock used as an inorganic mulch. (EF) Succulents offer a remarkable variety of shapes, sizes and textures and this diversity has been used to retain the integrity of the available space. For example, several of the beds are prevented from becoming too symmetrical by informal massed plantings of succulents from both the New and Old Worlds, including Africa, Madagascar and Saudi Arabia, giving the beds an air of rugged functionality. When the autumn equinox triggers a decline in the verdant greens of summer, revealing reds and yellows in the leaves of deciduous trees, it is an indication that the spiky aloes are ready to produce their towering candelabra-like inflorescences that will transform the beds into kaleidoscopes of colour. The open garden beds are not the only places where succulents thrive. Extensive collections of Old World aloes, euphorbias, crassulas, fatstemmed wild grapes, carrion flowers, mesembs and succulent daisies, as well as New World cacti, agaves and bromeliads, abound in well-kept collections. Over the past few years, gardening fashion has been regarded as lacking content, with an excess of mediocrity. To counter this, considerable effort is being made in public and private gardens to emphasise ‘green’, or environmentally sound, components. This is where succulents come into
their own, thanks to their remarkable variety of shapes, sizes and textures, as well as their longevity. The Desert Garden has been designed to be cherished forever, yet it is constantly being reinvented so that it remains fresh and relevant. In gardening, as in so many areas of life, sustainability is the true bulwark against our increasingly disposable culture. Through the commitment of a succession of garden directors and curators, the Huntington Botanical Gardens are leading by example in this area. MEDITERRANEAN CLIMATE Globally, regions described as having a ‘Mediterranean climate’ occur between latitudes 31 and 40, north and south of the equator, mainly on the western side of continents, but sometimes extending eastwards. Apart from the Mediterranean Basin, this includes coastal southern California, central Chile, southwestern Australia, and southwestern South Africa. FOUQUIERIA – AN EMBLEM OF AMERICA’S SOUTHWESTERN DESERTS The boojum tree (Fouquieria columnaris), a native of Baja California, is known for its bizarre appearance, which has been described as an upside-down, giant, spiny carrot. It is legally protected in part of its range. In the same family, the more widespread ocotillo (F. splendens) is a common sight in the Sonoran Desert. The Huntington Desert Garden has both species in cultivation, as well as other fouquierias from Mexico, which produce bright red blossoms for much of the year.
Fouquieria columnaris, the boojum tree, and F. splendens, the ocotillo, both originating from the deserts of the southwestern USA and northern Mexico, are cultivated in the Huntington Desert Garden. (EF)
Close-up of the spectacular crimson red, almost aloe-like, flowers of F. splendens. Some succulents, such as Echeveria pumila, remain low-growing and multiply rapidly, making them perfect ground covers in sunny spots.
Mammillaria compressa subsp. compressa, from Mexico, eventually forms large mounds. On farms and ranches, the easily cultivated Pachycereus marginatus is often grown to form living fences.
Some plants thrive in densely planted beds and are none the worse for being deprived of space. Here, different leaf and stem succulents contribute to the visual impact of the bed, which is bordered by a wide path for easy access. The tall, variously twisted orange inflorescences in the left and right middle ground belong to a hybrid of the succulent-leaved bromeliad, Dyckia fosteriana. Its small, bright orange flowers add colour to the beds in spring, a time when aloes, which are often relied on for succulent plant colour, are not in bloom. This succulent-leaved species is a relative of the pineapple, both belonging to the family Bromeliaceae. (EF)
Pachycereus schottii ‘Monstrosus’ is a strange, spineless form of the species. Its trunks resemble a small totem pole.
Potted collections of milkweeds (Euphorbia spp.), cacti, agaves, and other groups of succulents are kept in the Desert Garden Conservatory. These collections, which are used in teaching programmes, are open to the public.
These tall, imposing specimens of Yucca filifera have been in the Huntington Desert Garden for close to a century. (EF)
Shrubby agaves thriving in all their splendour. Although they will be of varying height when fully grown, these four species make useful shrubby ground covers (clockwise from top left): Agave schottii var. treleasei, Agave bracteosa, Agave mitis var. albidior (sometimes known as A. celsii var. albicans) and Agave ×leopoldii (a garden hybrid of A. filifera and A. filifera subsp. schidigera). They are all grown primarily for their interesting leaves and not their flowers, which only appear on tall inflorescence stalks after many years of vegetative growth.
Agave attenuata is one of the most commonly grown agaves in domestic gardens, along with Agave americana. This cultivar of A. attenuata, known as ‘Nova’, has blue leaves and the elephant trunklike inflorescence remains erect, rather than curving downwards as it usually does in this species.
A stark green corner can be given a fresh look by simply layering different types of succulent foliage, as has been done here beneath a magnificent specimen of Aloe barberae. (EF)
The flowers and inflorescence stalk of Hesperaloe parviflora, an Agave relative, are a bright pinkish red. Here, it contrasts with the blue leaves of Dasylirion wheeleri. Mexican creeping devil, Stenocereus eruca, makes an unconventional ground cover. The stems are armed with formidable spines.
As you have never seen them before! Beaucarnea recurvata, the ponytail palm, and Yucca elephantipes, the elephant’s foot yucca, seldom grow as magnificently as they do in San Marino.
Although these two succulent trees are widely cultivated in temperate parts of the world, they do exceptionally well in the mild climate of southern California. The dagger-like leaves of Agave filifera are sharply pointed, but lack marginal spines. The leaves are adorned with threads and white bud imprints, making it an attractive addition to any garden. Several species of the genus Cylindropuntia have become problem plants in parts of the world. The heavily armed C. echinocarpa (sometimes known as Opuntia wigginsii) shares a shrubby growth form with most species included in the genus.
Agave ×arizonica, a natural hybrid between A. chrysantha and A. toumeyana var. bella, occurs naturally in Arizona, where it benefits from conservation measures. Here it grows among other plants. FACT BOX ADDRESS: The Huntington Library, Art Collections, and Botanical Gardens: 1151 Oxford Road, San Marino, California, 91108, USA. CONTACT: Tel: +01 (626) 405-2100. OPENING HOURS: Summer: daily 10:30–16:30; Winter: Mon, Wed, Thu 12:00–16:30; Fri–Sun 10:30–16:30. Closed Tuesdays; also 25 December, 1 January, 4 July and Thanksgiving. BEST TIME TO VISIT: Throughout the year. COST: Entrance fee charged; discounts for seniors, students and children; free entry with advance tickets on first Thursday of every month. ATTRACTIONS: Gardens: Children’s Garden, Chinese and Japanese Gardens, Desert Garden, Camellia Collection, Shakespeare Garden, Jungle Garden, Lily Pond, Conservatory; Art Gallery, Library. FACILITIES: Tea room and café. No picnics. Free parking on site.
ACCESSIBILITY: All buildings and most gardens are wheelchair accessible. INFORMATION: http://www.huntington.org
The Taxodiaceae (Swamp pine or Taxodium family) includes the Coast redwoods (Sequoia sempervirens), the tallest trees living on Earth today. Native to northern California and southern Oregon, they can reach heights of over 110m.
The attractive yellow-striped, spiky-leaved Agave americana var. variegata can be easily grown as a hedge along a perimeter wall. The leaves of this variety are a combination of dark green and yellow, and tend to be variously twisted. In many ways, coastal California’s visually arresting natural landscapes and panoramic views of the Pacific Ocean feel tailor-made for lush and luxurious succulent plant cultivation. A journey from the top to the bottom of the state offers a veritable feast for succulent lovers. Many of the famous succulent gardens of California were created by ‘plant people’ – plant lovers and horticulturists, rather than by landscapers. Because very few small botanical gardens have the financial means to employ landscape architects, inevitably, these gardens tend to be in perpetual transition as they are lovingly transformed into contemporary havens, with past development decisions being amended; even reversed where necessary. The Ruth Bancroft Garden is a case in point. It was founded on the desire to create a diverse garden that was in harmony with the region’s Mediterraneanlike climate, and has generated an incredible botanical and horticultural legacy. Some forty years old, the Garden feels as if it has been around for almost as long as the surrounding hills. Indeed, this magnificent
little Garden is one of the treasures of Walnut Creek, an achingly beautiful part of northern California. Hubert Howe Bancroft, grandfather of Philip Bancroft Jr., was a flourishing businessman who arrived in California in the mid-1800s and eventually settled on a 162 hectare (400 acre) farm in the peaceful Ygnacio Valley, where the city of Walnut Creek is situated today. He planted walnut and pear orchards but, by the 1960s, as the city encroached on the original farm, the trees gradually made way for suburban development. Now, all that is left of the once-vast Bancroft estate is a 3 hectare (8 acre) family compound and an adjoining 1.4 hectare (3.5 acre) garden. Fortunately, the future of this tract of land is ensured, thanks to the involvement of The Garden Conservancy, a nonprofit organisation with a mission to preserve America’s garden heritage. GARDEN DESIGN WITH SUCCULENTS Succulent gardens tend to be naturally seductive, and not only to dedicated cactophiles and succulentologists. The very design of fat-bodied plants – their shapes and sizes – indicate that they were made to compete, not to boast beauty in the traditional sense.
A Californian gem, Giant sequoia (Sequoiadendron giganteum) is a member of the Cupressaceae or cypress family. Once distributed across most of the Northern Hemisphere, it is now restricted to a narrow range, with fewer than a hundred sites known along the western slopes of the Sierra Nevada. The species thrives in areas of high rainfall, heavy snow and cold nights, which are subjected to frequent fires. Ruth Bancroft (b. 1908) studied architecture and education at the University of California, Berkeley. She was always interested in plants and, after her marriage to Philip Bancroft Jr. in 1939, she began planting a garden around their cottage on the family estate. The Bancrofts moved into the main house in the mid-1950s and soon Ruth began collecting succulents, filling the windowsills of her house as well as a number of lathhouses, glasshouses and cold frames with plants she purchased on trips throughout southern California.
In 1972, as the last hectares of walnut trees were removed following their decline, Philip suggested that Ruth finally plant out her collection of cacti and succulents. She called in the services of nurseryman and garden designer, Lester Hawkins, of Western Hills Nursery, in Occidental, California, who created the layout of the beds and anchored them with rocks, boulders and carefully positioned trees. Hawkins was particularly adept at creating a balance between the need to display sculptural specimen plants and the overall impact of the garden vistas. During the design and construction phase, care was taken to give the raised beds excellent drainage, to counter the effect that endless days of soaking winter rain can have on fine-grained soil, which readily retains moisture. Good drainage is critical for succulents, as soggy or waterlogged soil can have a devastating effect on plants grown in the open. The San Francisco Bay Area has a Mediterranean climate, with warm, dry summers and wet, but fairly mild, winters. Although these conditions are generally very good for growing succulents, managing a predominantly succulent garden in Walnut Creek is not as simple as it sounds. The town is situated about 26 km inland, and in winter, temperatures can drop below freezing, with rain sometimes falling for days on end. In this location, succulents that originate from summer rainfall regions are subjected to winter rain and, with an average annual rainfall of around 500mm, even some winter rainfall species experience more rain here than they would get in their natural habitat. The excessive rainfall coupled with low winter temperatures means that many succulent species require protection. From October to April, the open beds are covered with polyethylene stretched, rather laboriously, over about 300 wooden frames. In spring, the protective covers are removed and the Garden is ceremoniously re-opened to the public. The ongoing success of Ruth Bancroft’s ‘dry desert garden’ is evident in the diversity of plants found in both the mature and the emerging collections, with their varying textures, architectural lines, sense of scale and use of colour. Plantings in the beds display an exemplary sense of form through the use of the tree-like Yucca aloifolia (Spanish bayonet) and Yucca filifera, along with other hardy tree species, such as Parkinsonia aculeata, the palo verde or Jerusalem thorn (a native of the Sonora and Chihuahua Deserts of the American southwest), and various species of the Australian genera
Eucalyptus and Brachychiton, with the occasional prickly pear (Opuntia spp.) to provide height and structure. Coastal Crassulaceae: Dudleya farinosa, or bluff lettuce, is indigenous to the San Francisco Bay Area. This Californian plakkie is well adapted to cultivation in areas of winter rainfall. It has pale blue to bluish green leaves that terminate in sharp, but harmless, tips. Around and beneath them, spreading carpets of colour are provided by a variety of erect, spherical, spiky, columnar and rosulate forms of agaves, aloes and yuccas. Tree-cacti provide accents, alongside echeverias, sedums, crassulas, graptopetalums, cotyledons, numerous species of mesemb, a few species of geranium (representatives of the genus Pelargonium) and many others. Indeed, it comes as a relief that, in this Garden, there is no monotony. The Garden is bisected by a network of neatly raked dirt paths that radiate from a 30-year-old gazebo-like pavilion, whose delicate latticework has been painted a soft green to merge into the tranquil surroundings. The paths lead the visitor past swathes of majestic agaves and towering yuccas, and allow for easy observation of miniature cacti in sensibly constructed beds. Shade houses provide protection for species considered too sensitive to survive in the open, while trees provide some relief from the summer heat. The paths running parallel to the shade houses echo the symmetry of the plants in the living collections.
Once the visitor has passed through the pavilion, confrontation is immediate: now the spiky forms of massed cacti, euphorbias, aloes and agaves invite close, but careful, exploration. For frequent visitors who are fortunate enough to be able to observe plants as they mature, there are new discoveries around every corner, as small, and not so small, cacti and succulents flourish under the protection of larger plants. Park benches are positioned at strategic points, allowing visitors to rest on a hot summer’s day, or to catch their breath while taking in the plantings. Next to the hustle and bustle of a busy Californian city, the Ruth Bancroft Garden is a welcome distraction. So entrancing are the collections that, for a few hours, the visitor can become completely absorbed by the sometimes bizarre beauty of the intriguing shapes and colours of the succulents and cacti.
Part of the beauty of a succulent garden lies in the fact that it is not necessary to wait for the next flowering season to obtain colour, as year-round colour is provided by the leaves and stems of these fascinating plants. And immense interest, of course, springs from the inexhaustible variety of plant forms. At the Ruth Bancroft Garden, every plant and landscaping detail tells a story, from this
massive, bottle-trunked Brachychiton rupestris from Australia, which almost rotted a few years ago, to the smallest cactus species. AGAVE COLLECTION The Ruth Bancroft Garden is known for its collection of mature, large-growing Agave species. The leaves of Agave americana var. mediopicta ‘Alba’ (above) have a sharply contrasting, broad, white central stripe.
In the case of this plant (above), which is perhaps best included in Agave americana var. mediopicta, only the narrow leaf margins are green, while the centres are bright yellow. As in many forms of Agave americana, the very long leaves are beautifully twisted.
The leaves of the widely grown Agave americana var. marginata are edged with yellow.
Placing succulents in a contemporary setting gives them a fresh, modern allure. For example, the spine-covered pads of Opuntia phaeacantha significantly contribute to the desert-like atmosphere of the Garden. Whether in flower or not, the strong architectural lines of this robust cactus species pleasantly combine with the tree-like yuccas with which it grows.
The advent of the flowering of an agave signals the end of its life. The basal part of the robust flowering pole of Agave chiapensis is covered with a protective layer of leaf-like bracts that add to the beauty of the plant at this stage of its life cycle. This species, a close relative of Agave mitis which is naturalised along the Mediterranean Basin in Europe, forms large clumps, so that every clone essentially survives for decades.
The Garden is crisscrossed by paths, which are framed by succulents of all shapes and sizes. Here, a striking cultivar of the miniature Sempervivum arachnoideum, sometimes known as ‘Cebanese’, nestles in a perfect habitat created by strategically placed rocks.
With its erect, densely spined stems, Cleistocactus hylacanthus serves as an eye-catching accent plant.
Eclectic minimalism in a succulent garden. The leaves of this agave cultivar, widely known as Agave ‘Cornelius’ (reputedly a selection of Agave americana), are wavy in two directions: up and down, and left to right. The light green leaves are edged with broad yellow bands, which adds to the charm of the cultivar. Here, it grows in a raked gravel bed.
When in flower, plants of Drosanthemum speciosum are completely covered with large, dazzlingly beautiful, crimson red flowers.
No story about the Ruth Bancroft Garden is complete without reference to the golden barrel cactus, Echinocactus grusonii. The size of this specimen is an indication of its considerable age. Close-up of the spined ribs which expand, concertina-fashion, when the species is not subjected to water stress.
Mesembs originating from South Africa’s winter rainfall region thrive in the Californian climate. One of these species, Lampranthus aurantiacus, has bright, butter-yellow flowers.
The stems of the cactus Oreocereus celsianus are covered in symmetrically arranged spines and tufts of hair. Ruschia pulvinaris a spectacular, ground-hugging mesemb with bright only a few centimetres. It grows in the purple flowers, is suitable for planting anywhere that a dense ground cover is required in a sunny spot.
The miniature Californian leaf succulent, Sedella pumila (also known as Parvisedum pumilum), the Sierra mock stone crop, attains a height of only a few centimetres. It grows in the Hetch Hetchy Valley in California’s Yosemite National Park, where snow is not uncommon. (EF)
Agaves come in many sizes, but the basic shape of a central axis around which fat, usually ferociously armed, leaves are arranged remains constant. One of the more desirable species to grow is Agave parryi var. parryi, which forms a rotund, almost ball-shaped, rosette of grey-green leaves. The production of a flowering pole signifies the end of the life of an agave. This magnificent specimen is entering the final phase of its life history.
The flowers of Ferocactus latispinus var. latispinus, one of the barrel cacti (sometimes treated as F. recurvus), occur in various shades of purplish red, with dark centres. Very rarely, a white-flowered form of the species is found in cultivation. FACT BOX
ADDRESS: The Ruth Bancroft Garden: 1552 Bancroft Road, Walnut Creek, California, USA. (On weekends or when the office is closed, use the North Entrance at 1500 Bancroft Rd.) OPENING HOURS: Daily 10:00–16:00. Closed 1 January, 4 July, some days in November, 25 December; closed for a fortnight in March/April (Spring preparation) and October/November (Winter preparation). BEST TIME TO VISIT: Year-round (note closure periods for seasonal preparation). COST: Entrance fee charged; free on first Tuesday of month. Concessions for seniors, students, children. ATTRACTIONS: Self-guided or docent-led tours. Plant sales. Workshops, seminars and public events are held throughout the year. FACILITIES AND ACCESSIBILITY: Limited parking at the Main and North entrances. Accessible by public transport (nearest BART station ±2.5 km). Wheelchair accessible, but paths are gravel. INFORMATION: http://www.ruthbancroftgarden.org
The spiky, otherworldly space that is the Jardín Botánico of UNAM. The signage in the Jardín Botánico is colourful and informative. This map shows the layout of the Jardín and guides visitors through the beds.
Raised beds, edged with rocks, allow good drainage of the areas where succulents are grown. There is something remarkably exotic, yet strangely familiar, about the Jardín Botánico del Instituto Biología de la Universidad Nacional Autónoma de México, or UNAM Botanical Garden, as it is usually called in English. The main reason is undoubtedly the many species of Mexico’s flagship genus, Agave, which grow cheek by jowl in carefully tended beds. Agaves, or century plants, are so widely cultivated, even naturalised, globally, that seeing them elsewhere invariably reminds one of home. Another reason for the familiarity is the ubiquitous, usually verdant green, kikuyu grass, Pennisetum clandestinum, which is used extensively on the campus as a lawn grass, as it is in many parts of the world. Mexico City, la Cuidad de México in Spanish, is the oldest capital in the New World. A sprawling metropolis, situated more or less at the centre of this wonderfully varied country with its wealth of history and culture, this very special city ranks as a must-visit destination. MULCHING
The surfaces of the open beds in the Jarím are variously covered in reddish or whitish pea-sized, crushed volcanic gravel that emphasises the beauty of the cacti and succulents. Using stones as mulch also ensures that the plants are kept clean and not splattered with mud, as is often the case in gardens where the soil is bare. Mulching is a waterwise gardening practice, and inorganic mulch helps to preserve soil moisture. Although Mexico City is situated in a valley, it lies at an altitude of ±2200m above sea level. Although the region has a temperate climate, it can still be fairly subtropical during the rainy season (June to October), with midsummer temperatures reaching the low 30s. Even in the cooler dry season (November to February), the temperature rarely drops below 3°C, with daytime temperatures hovering around 18°C. The average annual rainfall of Mexico City is quite high (± 800mm), falling mostly in summer. Hail occurs frequently. Mexico is regarded as one of the world’s mega-biodiverse countries. It has provided many gifts from its exceptionally rich plant diversity: chocolate, chillies, potatoes, pumpkins and squashes, corn, vanilla, avocados, prickly pear fruit and nopales (pads), as well as numerous other fruits and fruit-based products, including the liquor tequila. However, despite all these plants and their wild progenitors, for the average succulent plant enthusiast, the primary fascination with the Mexican flora is most likely to be the rich diversity of Cactaceae, Crassulaceae and Agavaceae. These are the three most speciose succulent plant families in the Americas, with hundreds of species included in each and, for all of them, Mexico is a significant centre of diversity.
A tree-like Furcraea martinezii, a representative of a genus closely related to Agave, makes a useful specimen plant.
Two massive inflorescence poles of Agave americana dominate the skyline and provide height to the plantings. The succulent plant tourist with sufficient time will want to visit Mexico’s wonderful natural landscapes, which are filled with a variety of these fascinating plants. But for the visitor with only a few days to spare, the Jardín Botánico offers a concentrated sample of the country’s succulent flora. The Jardín Botánico, which was established in 1959 at what is now the largest and oldest university in Latin America, is a tranquil place where one can escape the unrelenting pace of one of the world’s most populated cities. Lovers of Agave will find an immense variety of species cultivated in the Jardín Botánico. These range from miniature specimens to plants that grow to the size of a small family car. In Mexico, agaves are known colloquially as maguey (in the same way that all species of Aloe are known as aloes in English, or aalwyne in Afrikaans). Many species are of considerable economic importance, but perhaps none more so than those used to produce the alcoholic beverages mescal and pulque. Agave tequilana (suffixed with Weber ‘Azul’ for identification purposes) is used for the production of tequila, a type of mescal. Tequila is made by distilling the juices of mature,
harvested and fermented agave heads, or piñas, into hard liquor. The industry is based around the town of Tequila, from which the beverage takes its name, 50 km west of Guadalajara, in Jalisco province. Of course, many species of Agave are grown for their horticultural potential while others, such as A. lechuguilla, are useful sources of fibres for the production of ropes and cordage. The walls of the raised beds in the Jardín were constructed from the darkcoloured volcanic rock that occurs locally. This type of rock is rather porous but very hard. Nevertheless, large boulders have been fashioned into blocks of manageable size to create walls that fit together neatly, like a jigsaw puzzle. The porous nature of the rocks makes them perfect for growing small succulents that thrive in a well-drained medium. A number of unspoilt, solidified lava outcrops have been retained in the Jardín and the nearby grounds surrounding the Instituto de Biología, where they create an astonishingly ancient ambience. The raised beds are the pinnacle of eclectic minimalist gardening, consisting essentially of agave monocultures, interplanted with a smattering of smaller Mexican leaf, stem and caudiciform succulents. These include species of Sedum and Echeveria, two members of the Crassulaceae that are indigenous to Mexico. Sedum praealtum subsp. praealtum is useful for training into a low hedge for separating one planting from another. As in other parts of the world where it is cultivated, this species flowers in late winter, when little else is in bloom except, of course, the ever-popular aloes.
The fat, yellowish stems of Sedum frutescens are perfectly offset against a white, inorganic gravel mulch.