A Cactus Garden Takes Shape

The H Warren Buckner Cactus and Succulent Garden is a feature of the Water Conservation Garden, a five-acre demonstration garden at Cuyamaca College with a focused mission: “promoting water conservation in the Southern California landscape through programs and exhibits that educate and inspire the public.” The importance of this mission is becoming increasingly clear with each new prediction of water scarcity in our region. Events are planned at the Garden in association with Gardening Under Mediterranean Skies V in San Diego; the author will be a featured speaker.

When many Southern California gardeners hear the word xeriscape, an image of “zeroscape” comes to mind: a landscape with nothing but gravel and a few cactus scattered about. Here at the Water Conservation Garden, we knew that cactus and succulents had much more potential and, if treated with respect by a landscape designer, would result in a spectacular setting.

To help us create a cactus and succulent garden, we were fortunate to have the volunteer services of Michael Buckner, whose cactus garden designs are acknowledged as some of the finest in Southern California. Buckner, of Plant Man Nursery in San Diego, designed and constructed the garden in honor of his father, the Water Conservation Garden’s former president and longtime supporter, H Warren Buckner, who is also a well-known cactus maven.

Michael Buckner is a true landscape artist; working with him was an extraordinary experience. Our existing cactus garden was small and flat, with a pink gravel base and several cactus and succulents of various sizes. Buckner arrived in September 2005, not with a detailed blueprint but a vision for the garden that he sketched roughly on notebook paper. The flat look must go, he said, advising some topographic sculpting to create a dry streambed separating several isolated mounds. This trick made the twenty-by-twenty-foot main portion of the garden appear larger and offered entirely different views from different angles. Myrtle hedges that framed two sides were trimmed to give a wavy appearance that, from some viewpoints, runs parallel to the mounds and, at others, displays a pleasant contrast.

Thanks to generous donations from Western Cactus Enterprises, The Good Earth Nursery Inc, and C and J Cactus Nursery, Buckner brought with him several truckloads of plants, many simply dug from the ground. Once KRC Rock delivered its donation of a few tons of rocks, we were ready to begin. The final plant layout and installation happened nearly simultaneously as Buckner chose from the collection of donated plants scattered in our back lot and placed them precisely to complete his vision of the garden.

Installation

The end of September 2005 brought the hottest weather of the year, close to 110° F. As we cursed the bad timing, the conditions, nevertheless, seemed appropriate for a desert garden. We started with the grade changes, for which some serious mechanical equipment was needed to completed most of the grading, but, as we got deeper, we needed a trencher with rock teeth to loosen the “soil” when the loader complained.

We then built the planting mounds using a mixture of seventy percent composted topsoil and thirty percent pumice. Buckner’s ideal cactus soil mix holds moisture but also ensures that sufficient air enters the soil. The existing irrigation system was deemed adequate. We thought it best to use overhead sprinklers because of the density and complexity of the plantings. A drip system would have been time-consuming and difficult to install (and maintain) around the spiny plants. We liked the advantage of simulating natural rainfall with the sprinkler irrigation to wash off dust that collects on plants and rocks here, where no rain may fall for more than six months at a time. We used MP Rotator nozzles on the popup sprinklers to increase the system’s application uniformity and keep it as efficient as possible.

The back mound was planted first and included a sixty-year-old elephant-foot palm (Beaucarnea recurvata) that the Buckner family had purchased in a one-gallon container in 1945. We positioned it at an angle to add interest to the sight lines. Next to be placed, again at an angle, was a huge golden barrel cactus (Echinocactus grusonii) that had been propagated thirty-four years ago by a nine-year-old boy. His father, a local nurseryman, asked that it be planted in the garden as a memorial to his son, who had died in an automobile accident. This 300-pound ball of thorns was wrapped in old carpeting and strapped to a large hand truck to haul it from the nursery. We moved it by loader to within fifteen feet of its final destination, where four people dragged it up the mound, still wrapped in carpeting (mainly to protect us!).

We placed the stream foundation rocks next. These large, blocky pieces were set both to give definition to the stream and to solidly anchor the mounds. Buckner then painstakingly placed the multicolored river rocks, one by one on end (instead of flat) to give character to the stream bottom and to create the suggestion of flowing water. This beautiful rounded rock is an abundant resource in San Diego County, where an ancient river once flowed. The remainder of the cactus and succulents were then positioned to create vibrant compositions of shape, color, and texture.

The Plants

Our cactus garden includes sixty-six species and cultivars of cactus and succulents from all over the world. The local flora is represented by palo verde (Parkinsonia ‘Desert Museum’ and Parkinsonia aculeata), desert agave (Agave deserti), and purple prickly pear (Opuntia santarita), to name a few. From Africa come Euphorbia, Kalanchoe, Aloe, and Pachypodium; from Mexico, Cleistocactus, Ferocactus, Mammillaria, and Echeveria; from USA and Mexico, Echinocactus, and from South America, Gynoocalycium, and Echinopsis. In April, Echinopsis x Lobivia, a South American hybrid, produces massive, bright pink flowers that are showstoppers for the few days that they are on display. The flowers are reminiscent of a skyrocket, as the buds slowly develop over the course of a week to give a brief explosion of brilliant color and texture.

The Great January Freeze

A deep freeze that occurred in January 2007 left its mark everywhere in the garden (and throughout much of San Diego County), but most notably in our new cactus garden. The rarity of a temperature as low as 18° F was equaled only by the duration of the cold weather; many of the cactus and succulents suffered. Portulacaria afra ‘Variegata’ and Kalanchoe luciae subsp. luciae froze nearly to the ground but have since begun to recover from their roots. The sixty-year-old elephant-foot palm took a severe hit and lost two of its taller branches. A fine specimen of Pilosocereus purpusii cactus from Mexico suffered some tip dieback on its three-feet-long branches. Jade plant (Crassula ovata) and Aeonium arboreum ‘Zwartkop’ were severely damaged and had to be replaced.

Several other plants died completely, including Kumara plicatilis, Euphorbia stenoclada, E. milii x lomii, and Kalanchoe beharensis. Some of these have been replaced; others were simply removed. After a late winter plant replenishment and some warm weather that encouraged the damaged plants to regrow, the cactus and succulent garden looks as splendid as ever.

We continue to receive great feedback from visitors. Some say they are surprised to see such a rich mixture of color, texture, and form in the cactus garden. Others sit and study the garden for long periods, taking in a wide variety of inspiring views. Some remark that, when they look at it from different perspectives, it’s hard to believe they’re in the same garden. It’s also a favorite spot for photographers, who capture the ever-changing displays of light and shadow that move across the garden from morning till evening. We are proud to have such a gem to share.-

H Warren Buckner Cactus and Succulent Garden Plant List

The following trees, cactus, and succulents have been prime elements in this garden and should thrive in most parts of San Diego County, as well as elsewhere in Southern California.

Trees (and tree-like succulents)

x Parkinsonia ‘Desert Museum’ (syn. Cercidium ‘Desert Museum’), hybrid palo verde

Parkinsonia aculeata, Mexican palo verde

Yucca aloifolia, Spanish bayonet

Yucca elephantipes, giant yucca

Cactus (family: Cactaceae)

Cephalocereus senilis

Cipocereus bradei

Cochemiea poselgeri

Cleistocactus hyalacanthus

Cleistocactus strausii

Echinocactus grusonii, golden barrel cactus

Echinopsis x Lobivia hybrids

Ferocactus glaucescens

Ferocactus gracilis

Gymnocalycium baldianum

Gymnocalycium saglionis

Lophocereus schottii

Mammillaria compressa

Mammillaria muehlenpfordtii

Mammillaria mystax

Mammillaria parkinsonii

Mammillaria pringlei

Myrtillocactus cochal

Myrtillocactus geometrizans

Opuntia santa-rita

Soehrensia tarijensis

Succulents (other than cactus)

Aeonium arboreum ‘Zwartkop’

Aeonium ‘Kiwi’

Agave attenuata, fox-tail agave

Agave bracteosa

Agave deserti subsp. simplex

Agave filifera

Agave geminiflora

Agave schidigera

Agave x leopoldii

Agave parryi var. truncata

Agave potatorum var. verschaffeltii

Agave tequilana ‘Variegata’

Aloe brevifolia

Aloe cameronii

Aloe dorotheae

Beaucarnea recurvata, elephant-foot palm

Cistanthe grandiflora

Crassula ovata ‘Hummel’s Sunset’, jade plant

Dasylirion wheeleri

Deuterocohnia brevifolia

Deuterocohnia lorentziana

Echeveria hybrids

Euphorbia x lomii (Thailand hybrids), giant crown of thorns hybrids

Euphorbia ammak variegata

Euphorbia tirucalli ‘Sticks on Fire’

xGraptoveria hybrids

Graptopetalum paraguayense, ghost plant

Kalanchoe luciae subsp. luciae

Kalanchoe marmorata

Kalanchoe pumila

Kumara plicatilis, fan aloe

Pachypodium geayi

Pachypodium lamerei

Portulacaria afra var. foliis-variegata, variegated elephant bush

Sedum adolphi

Sedum brevifolium

Sedum rupicola

Senecio talinoides subsp. cylindricus

Senecio talinoides subsp. mandraliscae

Yucca rostrata, beaked yucca