removed from, and in some respects superior to, the traditional gardens associated with Italian villas. With the Giardini Botanici Hanbury now under the management of the University of Genoa, it is just a matter of time before it again takes its rightful place as one of the world’s major succulent plant gardens. This will finally do justice to Sir Thomas Hanbury’s gardening mission to distribute plant material as a means of promoting a love of Nature. Tempietto delle Quattro Stagioni, the Temple of Four Seasons, in the garden at La Mortola.
The deep blue floral spires of Echium fastuosum, from the Canary Islands, echo the purple of the jacaranda flowers.
As indicated by the production of a central flowering pole and collapsing leaves, the specimen of Agave salmiana var. ferox in the background has come to the end of its life. A large, blue-leaved Agave franzosinii can be seen on the right, while medium-sized, dark green rosettes of Agave ghiesbreghtii grow in the left foreground.
A cypress avenue, the Viale de Cipressi, leads in an easterly direction towards the Mediterranean Sea; here, succulents are interplanted with a variety of other plant forms and textures.
Yucca elephantipes is arguably the most widely cultivated of all the species of Yucca grown in the Mediterranean, if not in the world. The branches of this stately, very old, specimen are clothed in the remains of dried leaves, a sight not often seen in gardens, where the tendency is to keep the branches devoid of dried leaves.
Species of Aloe were some of Sir Thomas Hanbury’s favourite plants. This beautiful, creeping species is often called Aloe mitriformis in European collections. However, the flowers, which are borne in high summer, are invariably arranged into an inflorescence in the shape of a cone (inset), likely indicating that it is the hybrid widely known as Aloe ×nobilis. In habitat, representatives of Aloe mitriformis usually have flattened, head-shaped flower clusters.
One of the agave beds. Sir Thomas Hanbury had a special fondness for these prickly plants from the New World. Agave salmiana var. salmiana grows in the background, with its var. ferox in front of it.
The leaves do not have marginal spines, but the rosettes uncannily resemble those of aloes and agaves. The nectar-laden flowers of Doryanthes palmeri are bright red.
A stone vase planted with a hybrid between Aloe humilis and Aloe arborescens is placed on top of a pillar at the start of the Scala delle Anfore, the Amphora stairway.
The leaf margins of Agave titanota are adorned with architectural, white bony margins. The unfolding leaves impart bud imprints on the central cone of emerging leaves.
A dense planting of succulents, with Agave americana var. marginata in the centre foreground.
A South African bulb, Scadoxus puniceus.
Cork oak, Quercus suber, a mainstay of Mediterranean wooded regions, also flourishes in the Hanbury Garden.
The presence of ancient olive trees indicates that the area has been used for olive cultivation for several centuries.
Cypress trees form a narrow, shady avenue that focuses the view towards the Mediterranean Sea in the distance.
Large shrubs of Yucca elephantipes grow in the central bed in front of the Palazzo Orengo. The leaves of this plant have broad, yellow central stripes, rather than yellow leaf margins, as found in a more widely cultivated form. Only a skeleton of green remains on this variegated specimen of Opuntia monacantha. The developing buds appear blood red.
Yucca whipplei, commonly known as the Lord’s candle, is a recent arrival at the Hanbury Garden.
The inflorescence consists of hundreds of bell-shaped white and purple flowers.
Contrasting defence mechanisms. The soft, grass tuftlike appearance of the rosettes of Dasylirion wheeleri (sometimes referred to as D. glaucophyllum) belies the fact that the margins are armed with needle-sharp spines. The leaf tips, ending in a hairy tuft, are soft and harmless though. In contrast, the leaf margins of Agave stricta are smooth, but the leaf tips are very sharp. If well grown, these two species make perfect specimen container plants, but keep them away from human traffic and inquisitive pets!
The leaves of Agave attenuata shimmer in the last rays of a Mediterranean sunset. The species, commonly known as elephant’s trunk, flowers only once after many years of growth – typically more than a decade – to produce a massive, gracefully arched inflorescence that carries thousands of flowers. FACT BOX The Hanbury Garden is also known as Giardini Botanici Hanbury or Villa Hanbury. ADDRESS: Corso Montecarlo 43, Mortola Inferiore, 18039 La Mortola, Ventimiglia, Italy. (Villa Hanbury is located several kilometres west of Ventimiglia, on the Italian Riviera, close to the French border. Access is via the scenic coastal road from Monaco, through Menton.) OPENING HOURS: Daily; times vary with the season. Closed Mondays (Nov–Feb). COST: Entrance fee charged. Discounts for students and children.
ATTRACTIONS: Nine hectares under cultivation. Species from all six Mediterranean climate zones in the world are represented. Other attractions include the Villa Loggia terrace, a stretch of Roman road, grottos, fountains, garden statuary, a bronze dragon from Kyoto, a Japanese bell (c.1764), Moroccan pavilion (Hanbury family tomb), and a mosaic of Marco Polo. Palazzo Orengo is not open to the public. FACILITIES: Snack bar beside the sea. INFORMATION: http://www.giardinihanbury.com
Most of the material in cultivation at the Sukkulenten-Sammlung has to be kept under glass, as many of the plants will not survive Switzerland’s high rainfall and low winter temperatures. (EF)
The Sukkulenten-Sammlung is situated on Mythenquai on the banks of Lake Zürich, or Zürichsee, which is popular for yachting under favourable weather conditions. To the uninitiated, the sometimes stark appearance of succulents may shock, but behind their apparently callous and often prickly exterior lies a wealth of biotechnology that – over time – has made these plants colonisers of some of the Earth’s harshest and most arid environments. Most people are surprised to learn that one of the most comprehensive collections of succulents in the world can be found in Zürich, a cosmopolitan city in the heart of Europe. The surrounding verdant green valleys, tranquil lakes, alpine flora-covered slopes, snow-capped mountains, thundering waterfalls and deep gorges are landscape features not often associated with succulent plant habitats, especially not in Europe. The collection started in the early 1930s with around 1500 specimens, mostly cactus species; today it holds 25,000 specimens representing about 8500 different cactus and succulent species spread across some 30 families. This figure becomes even more significant if it is borne in mind that there are only about 10,000 different succulent plant types in the world. But, with a mean annual rainfall of 1200mm, and winter temperatures that can easily drop to -10°C, maintaining a thriving succulent plant
collection in Switzerland presents significant challenges. For this reason, the plants are mostly kept in glasshouses, cold frames and lean-tos. A consequence of this protection is that several specimens have attained magnificently mature dimensions. As with many international succulent collections, the SukkulentenSammlung Zürich, or Zürich Succulent Plant Collection, was built on, and expanded from, the interest of a single individual: plant breeder and cactus dealer Jakob Gasser, who established the core collection early in the 20th century. When Gasser’s health started failing, he intended to sell the collection of plants individually but, fortunately, it was acquired by Julius Brann, who bought it for 20,000 Swiss francs and donated it to the city of Zürich. The value of the collection was realised by a group of fellow plant enthusiasts, who persuaded the Zürich city officials to adopt and care for it in a greenhouse of the former city nursery. In 1931, the collection was opened to the public at its present location, not far from the city centre. At the time, it was kept in a single greenhouse that was erected at a cost of 36,000 Swiss francs. Since these humble beginnings, which coincided with the Great Depression, thousands of new accessions have been added and tens of thousands of visitors have enjoyed the glass-enclosed collection.
The entrance to the Sukkulenten-Sammlung is flanked by raised beds in which a variety of hardy succulents have been planted. (EF)
Planted cheek by jowl to maximise available space, these columnar cacti are grown indoors at the Sukkulenten-Sammlung. These plants can be planted densely and will, in time, develop into healthy, mature specimens utilising a minimum of available root space, and seemingly benefiting from competition against the roots of their neighbours. CAREFUL WITH CACTI
Only a single species of cactus is indigenous to South Africa: Rhipsalis baccifera subsp. mauritiana, the rope cactus, so called because of its thin, twine-like stems. However, over three dozen imported cactus species have become problem plants in this country, as well as in other parts of the world where the prevalent climate approximates their native New World habitats. Because they grow in the absence of natural enemies, these ‘alien invaders’ have become rampant weeds that can thrive to the point where they start to exclude the indigenous flora. If you want to cultivate cactus species in your garden, take utmost care to confine them so that neither the plants nor their seeds can escape. One of the most infamous invasive cactus pests in South Africa is the spiny form of Opuntia ficus-indica, the common prickly pear. As the popularity of the collection grew among local and international visitors, and the collection itself expanded through a programme of acquiring plant material from other parts of the world, it became obvious that more glassed-in display areas would be needed. As a result, at intervals of roughly 20 years, in 1948, 1961 and again in the early 1980s, further greenhouses were added to the original one. The Sukkulenten-Sammlung Zürich is situated two kilometres from the old city, on Mythenquai, next to Lake Zürich. Apart from the glasshouses, there are fenced-off beds and outdoor open areas where, against all odds, some succulents and cacti survive the region’s high rainfall and harsh winters – Zürichsee has been known to freeze completely. Only the hardiest succulents, from North America and elsewhere, were selected for cultivation in the open, landscaped beds. The display glasshouses, where the vast majority of the plants are kept, are mostly dedicated to plants from specific regions – there are houses dedicated to North American and Madagascan plants, for example – which allows for better control and simulation of the climate prevalent in the plants’ natural habitats. The much smaller cold frames are useful for overwintering and for acclimatising plants for later use in beds in the display houses.
Regardless of whether one is interested in Madagascan euphorbias, columnar or globular cacti from South America, African aloes, or New World agaves, the Sukkulenten-Sammlung Zürich is worth a visit. It not only allows visitors – about 50,000 per year – to experience and obtain information on the wonderful world of cacti and succulents but, nowadays, also runs education programmes through which the visitor experience is enhanced.
A selection of Pelargonium species, including the succulentleaved Pelargonium peltatum from South Africa’s Eastern Cape Province, has been used in a centuries-old breeding programme that resulted in the exquisitely beautiful hybrids that are today available in much of Europe. This one, with its large clusters of blood red flowers, fringes the eating area of a restaurant in downtown Zürich. Rather confusingly, these Pelargonium hybrids are known as geraniums in Europe; in Afrikaans they are known as malvas.
A magnificent specimen of a Columnea cultivar, similar to Columnea ×banksia, growing in a hanging basket in the foyer of the Sukkulenten-Sammlung. It has distinctly succulent leaves, and produces bright red flowers.
Continental Europe is well known for its beds of tulips in bloom in late summer. These bulbs, planted en masse for maximum effect when they flower in early- to mid-spring, grow on the campus of the University of Zürich. The bright red one is the water-lily tulip, a cultivar, ‘Showwinner’, in the Tulipa kaufmanniana group, and the one with yellow flowers with red centres is ‘Engadin’ in the Tulipa greigii group. These plants survive the winter as underground bulbs, which is not a common survival mechanism among succulent plants. GROWING SUCCULENTS IN CONTAINERS Most specimens at the Sukkulenten-Sammlung grow in containers, including mobile ones that can be moved indoors or kept under glass when conditions dictate. Succulents that live in small soil pockets in their natural habitat are perfectly adapted to growing in containers. These species, including cliff-dwellers and those that grow in the forks of trees, tolerate very high rainfall in nature, provided the substrate is well drained. Succulents hate ‘wet feet’: a combination of waterlogged soil and low temperatures are the perfect conditions under which they will rot. To grow succulents successfully in containers, invest in a well-drained, compost-rich soil mixture from your nursery.
The rat’s tail cactus, Disocactus flagelliformis, tolerates high rainfall in its native habitat in Mexico, where it thrives in locally dry sites, such as the forks of trees or on cliff faces, but it will not survive in the open in Zürich’s low winter temperatures. With its bold purplish pink flowers, the species makes a perfect trailing specimen for cultivation in a hanging basket, provided it is kept in a shady spot on a patio.
Here, two agaves are grown as tub plants in the foyer of the Sukkulenten-Sammlung greenhouse complex. Agave parryi var. parryi (centre) and Agave cocui (right) will happily grow for many years in containers where their roots are confined. In nature, A. parryi can tolerate temperatures as low -10°C, but A. cocui, the only agave that occurs naturally in the northern parts of Venezuela, prefers much higher winter minima.
The outdoor beds at the Sukkulenten-Sammlung consist of several sections dedicated to lowgrowing, hardy succulents such as sedums. The lack of height does not distract from the interest created by using a variety of different leaf colour forms. The low-growing cactus on the right is Opuntia humifusa, a creeping to shortly shrubby North American species. WHAT IS A CULTIVAR? From the earliest time, humans have depended on plants for their daily survival. Over millennia, humans found that they could improve on species with desirable floral, fruit or vegetative characters, by selecting and preferentially growing superior forms or variants of the typical species. These have become known as cultivars, a word derived from cultivated variety. For example, ‘Granny Smith’ apples are a cultivar (strain) of apple widely grown today for the sharp and tangy taste of the fruit.
This magnificent specimen of Abromeitiella brevifolia, a cousin of the pineapple, consists of thousands of densely packed small rosettes that form large, ant heap-like mounds of up to one metre across. Switzerland is not rich in indigenous succulents, but this stonecrop species, Sedum sexangulare, with its smooth, miniature, jellybean-like leaves, originates in continental Europe, where it is widespread. Here it grows in a thick mat on a well-drained rock sheet in the Botanical Garden of the Institute of Botany in Pruhonice, near Prague in the Czech Republic, where it also occurs naturally. THE DEVIL IS IN THE DETAIL Attention to detail ensures that a garden always has plenty to keep you engaged. If you are fortunate enough to have access to visually pleasing rocks and boulders, fill any cracks or
hollows with soil and plant them with rock-loving succulent plants to make an excellent talking point. Agave nickelsiae (sometimes referred to as Agave ferdinandi-regis, and previously included in Agave victoriae-reginae), grows happily in a plant bed in one of the greenhouses at the SukkulentenSammlung. CACTUS BLOOMS The flowers of most species of cacti are fairly short-lived, lasting for just a few days. But what they lack in terms of floral longevity, they make up for in the size and striking colours of their blooms. These delicate flowers of Echinocereus engelmannii are a remarkable bright ice-cream pink colour.
Hatiora salicornioides is commonly known as the beer bottle cactus in reference to the shape of its stem segments. This Brazilian species needs to be kept under glass if it is to be grown successfully in central Europe. It grows best in a hanging basket filled with a well-drained soil mixture. The flowers are brilliant yellow, if somewhat small.
The modern flair of this part of an outdoor bed in the Sukkulenten-Sammlung owes much to its striking multi-chromatic combinations: the jade green of the pads of the low-growing Opuntia humifusa and its fruits that are tinged with orange, provide contrast with the black, grey and white pebbles and rocks used as an inorganic mulch.
A small collection of hardy succulents is kept in outdoor beds or pots at the Sukkulenten-Sammlung. Euphorbia myrsinites subsp. myrsinites has small, pointed leaves but the real selling point is the flower clusters, or cyathia – a type of inflorescence – that are surrounded by bright yellow floral leaves. These plants, which do not easily strike root from cuttings, brighten up a sunny spot near the entrance to the collection. Many Opuntia, or prickly pear, species are kept in the collections of the Sammlung. The flowers of Opuntia basilaris are bright pink. FACT BOX ADDRESS: Sukkulenten-Sammlung Zürich: Mythenquai 88, CH8002 Zürich, Switzerland. CONTACT: Tel: +41 (0)43 344 34 80; Fax: +41 (0)43 344 34 88; email: [email protected] OPENING HOURS: Open daily 09:00–16:30.
BEST TIME TO VISIT: Year-round; outdoor plants may be covered in winter to protect against frost. COST: No entrance fee. ATTRACTIONS: Six greenhouses, 16 heatable cold frames, outdoor beds, regular special exhibits. Guided tours on request. ACCESSIBILITY: Accessible via public transport (tram and bus); parking nearby. INFORMATION: http://www.stadt-zuerich.ch/sukkulenten / http://www.foerderverein.ch
The tall, dried inflorescences of two specimens of Agave chrysantha signify that they have come to the end of their life cycles, while the trunks and arms of Carnegiea gigantea reach for the sky.
The blue-leaved Yucca rigida thrives in dappled shade. The persistent dry leaves point downward and form a skirt that surrounds and protects the stem. Innovation and passion – key elements of design – are often evident in gardens that have been developed by several generations of inspirational horticulturists and landscapers. The Boyce Thompson Arboretum, on the outskirts of Superior, Arizona, is no exception. Established in the 1920s, the Arboretum has undergone many changes since then, as successive curators have worked towards achieving its purpose of reflecting what is possible in dry-climate horticulture and showcasing plants that thrive under desert conditions. Nowadays, the Arboretum has a tranquil atmosphere, although the garden design exudes confidence and optimism: remixing and re-
mastering swathes of favourite plants into a landscaping approach that is young, fresh, and contemporary. In the field of cultivating plants that thrive in arid lands, the Arboretum can be very proud that, within its boundaries, it has one of the largest manmade arid zone forests in the world.
Typical cowboy country. The red cliffs of Picketpost Mountain dominate the skyline of the Boyce Thompson Arboretum. The slopes of the ridge are dotted with Carnegiea gigantea (saguaro) and Agave chrysantha (golden flowered agave).
WHAT IS A XERISCAPE? The term xeriscape – from the Greek word xeros (dry) and landscape – was coined in 1981 by a task force concerned with the inordinate amount of water applied to ever-thirsty domestic and municipal gardens in the arid, western parts of the USA. Today, this method of gardening in harmony with prevailing climatic conditions in arid zones – even in deserts – is firmly established worldwide as a viable way of creating an adaptable, waterwise haven for plants and animals. Boyce Thompson Arboretum is the oldest and, at 435 hectares, the largest botanical garden in Arizona, indeed in the southwestern USA. It features a magnificent range of plants – some 3200 species in total – with over 12,000 accessioned individual plants, including magnificent mature trees from the deserts and arid regions of the world. The Arboretum was created in the 1920s to help cultivate an appreciation of plants from the world’s deserts. The idea came to ‘Colonel’ William Boyce Thompson (13 May 1869–27 June 1930) in 1917, during World War I, while he was leading a Red Cross expedition to bring humanitarian relief to the inhabitants of St Petersburg, who had just overthrown the Russian Tsar. On his long journey through the arid Asian steppes, Boyce Thompson was impressed with how the local people made use of indigenous plants to stave off starvation and malnutrition, and he made the decision that when he returned home, he would create a haven where desert plants could be collected, studied and propagated for the benefit of humankind. At the Arboretum, succulents exist in almost biblical abundance and beauty, yet the garden is unassuming and unpretentious. As you approach, via US Highway 60, the first thing that impacts are the red cliffs of Picketpost Mountain, which is dominated by a magma ridge of soft volcanic rock known as Arnett rhyolite. This low range, which reaches a height of about 1300m, is dotted with Carnegiea gigantea (saguaro) and Agave chrysantha (golden flowered agave) – just like a scene from a Western movie. Against this backdrop, the Arboretum staff have created an oasis alongside Queen Creek, an intermittent desert stream that flows through the canyon. This is a perfect place to view plants originating from
the arid regions of Africa, Australia, Asia, South America and the Mediterranean Basin. For many people, gardening connects the mind, body and spirit. Wandering among the beds at the Arboretum evokes a meditative journey. Here, you can see what can be done in an arid environment; hopefully, this will encourage you to try new things in your own garden. Although, of course, desert gardening often requires more effort than gardening under more congenial conditions! The Arboretum is world-renowned for its aloe, cactus and agave collections. Old and New World species and styles are deliberately merged in a manner that is intended to break down boundaries and misconceptions. The horticulturally most successful of these wonderfully varied plants have been enthusiastically integrated into this desert garden, including many drought-tolerant and cold-tolerant species that thrive in extremely arid environments and which are much sought-after by domestic gardeners and landscapers worldwide. In terms of the Old World genus Aloe, the Arboretum is well known for its collection of highly floriferous artificial hybrids that are grown en masse in the beds and alongside some of the trails. One such hybrid, giving every indication that its parentage is Aloe claviflora × Aloe grandidentata, carries masses of dull red flowers in spring. Aloe vera, another species that is widely cultivated in the Arboretum has, since ancient times, been utilised for the medicinal, cosmetic and other uses of its sap and leaf juices.
An exquisitely beautiful tree euphorbia made from stone. This artwork forms part of the Chapungu collection of Zimbabwean stone sculptures which has visited the Arboretum, as well as many other botanical gardens around the world. Aloe vera, known in Arizona as the medicinal aloe, is common in the Arboretum. This Aloe species is popular in domestic gardens throughout the southwestern USA.