An Undersea Garden

By: David Ehrlinger

David Ehrlinger has a background in botany from the University of Michigan. After several years as head of horticulture for…

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The new Undersea Garden outside the Ecke Building at Quail Botanical Gardens in Encinitas, California. Photographs by Bob Wigand

The new Undersea Garden outside the Ecke Building at Quail Botanical Gardens in Encinitas, California. Photographs by Bob Wigand

The underseas world of exotic coral reefs is a dazzling spectacle that has long fascinated divers and snorkelers. Shoals of bright fish weave among colorful coral outcrops, while an array of marine life in a variety of forms, patterns, and hues inhabits the sea floor. Corals, sponges, and sea anemones so resemble plants that coral reefs look like underwater cultivated gardens. Exploring the reverse of that mimicry is a garden that opened in January, 2005, at Quail Botanical Gardens (QBG) in Encinitas, California.

An array of succulents mimicking marine life fills the beds of the Undersea Garden

An array of succulents mimicking marine life fills the beds of the Undersea Garden

In 2002, Jeff Moore, owner of Solana Succulents in nearby Solana Beach, decided to use a variety of succulents that resembled marine life for an underseas-themed display at the annual Del Mar Fair. Combining his snorkeling experience with horticultural expertise, Jeff created an award-winning display and followed a year later with a larger exhibit. In 2004, he created a major display on the East Coast at the Philadelphia Flower Show, in addition to a small garden at Sea World in San Diego.

In the fall of 2004, Jeff agreed to do a permanent garden, sponsored by the San Diego Horticultural Society (SDHS), at Quail Botanical Gardens. Bill Teague, staff horticulturist at the garden and a San Diego Horticultural Society board member, assisted in the installation, while several local nurseries and suppliers donated plants and boulders.

Quail Botanical Gardens is located twenty-five miles north of San Diego and a mere half mile from the coast, so the new garden’s underseas theme fits the local beach/surfer identity well. A wide selection of tender succulents can easily grow at this mild, practically frost-free site (Sunset zone 24, USDA hardiness zone 10).

For many gardeners, especially those from temperate climates, cactus and succulent plantings have an unfamiliar, otherworldly appearance. Many desert plants bear a vague resemblance to marine plants, corals, sponges, and other sea life. Admittedly, the fancied resemblance of a desert plant to a marine invertebrate animal is a personal and subjective perception. To the beholder, it is simply an unfamiliar plant and it is often uncertain exactly what kind of marine organism it resembles. This unfamiliarity is enhanced when many strange plants are massed in unusual combinations and situations, as they are here.

Languid sea-weed-like Epiphyllum drape over the rock at left; starfish-like Dyckia and Agave highlight the middle; and crested forms of Euphorbia mimic coral formations

Languid sea-weed-like Epiphyllum drape over the rock at left; starfish-like Dyckia and Agave highlight the middle; and crested forms of Euphorbia mimic coral formations

Endlessly Fascinating Mimicry

A plastic coral fish adds realism to a vignette of sea-grass-like ponytail palm (Beaucarnia recurvata) against volcanic rock

A plastic coral fish adds realism to a vignette of sea-grass-like ponytail palm (Beaucarnia recurvata) against volcanic rock

Throughout QBG’s Undersea Garden, large specimen ponytail palms (Beaucarnea recurvata) provide the “look” of large-scale seaweed. South African Bulbine and some miniature aloes add small-scale sea grass effects, plus seasonal floral colors. A wonderful, but odd ice plant (Glottiphyllum) has thick, glossy, kelp-like leaves. The sparse green stalks of lady’s slipper (Pedilanthus macrocarpus) look like wave-swept sponges or algae. Planted in masses, dinner plate aeoniums (Aeonium tabuliforme) are striking in the seascape. Epiphytic cacti (Epiphyllum and Rhipsalis paradoxa), several unusual cycads, and cultivars of the watch chain crassula (Crassula muscosa) add distinctive botanical accents. Quirky succulents, such as climbing onion (Bowiea volubilis) and Ceropegia dichotoma, add further vegetative diversity.

Unusual crested cacti (Myrtillocactus geometrizans) are notable for their blue green crenulations, reminiscent of brain coral. Alluaudia procera and Didierea trollii, with their weirdly rigid branching habits, suggest seaweed or even bizarre sponges. Large mounded specimens of a terrestrial bromeliad (Deuterocohnia brevifolia) mimic coral masses. Euphorbia tirucalli ‘Sticks on Fire’ lends an orange coralloid ambiance, while Aeonium ‘Cyclops,’ Neoregelia ‘Fireball,’ and various hybrid crassulas add red and purple hues to the composition.

Other plants resemble different kinds of marine creatures. The curved leaves of another terrestrial bromeliad (Dyckia marnier-lapostollei) suggest the twisting tentacles of an octopus cautiously exploring its realm. Other small dyckias resemble sea stars and starfish. The aptly named octopus agave (Agave vilmoriniana) and squid agave (Agave bracteosa) mimic familiar tentacled denizens of the sea.

Bearing a strong resemblance to sea anemones are these Dudleya species

Bearing a strong resemblance to sea anemones are these Dudleya species

Several of California’s tubular-leafed live-forevers (Dudleya edulis, D. hassei, and D. candida) bear a striking resemblance to sea anemones. Similar in character are several species of South African Senecio, especially S. scaposus, as well as various ice plants and small euphorbias like Medusa’s head (Euphorbia caput-medusa). Images of different kinds of anemone are evoked by taller, broad-leafed aeoniums. Combinations of all of these are effective in representing the multiple colors, forms, and sizes of the appealing sea anemones.

The frilled and colorful foliage of some of  the hybrid echeverias, especially planted in groups, present a certain jellyfish-like appearance. The well-named starfish flower (Stapelia gigantea) produces flowers resembling the plant’s marine namesake. When not in bloom, the swollen stems of stapelias resemble colonies of small sea cucumbers. Similarly, small cacti and euphorbs (Euphorbia horrida, for example) plausibly resemble other marine creatures. Euphorbia obesa, in particular, bears the common name of sea urchin plant (although it is better known as baseball plant).

Looking like colonies of marine worms is a cultivar of the common jade plant (Crassula ovata ‘Gollum’). Miniature baby’s toes (Fenestraria rhopalophylla) recall cute little marine organisms, while clusters of tiger’s jaws (Faucaria) have a more sinister, predatory presence.

For more northerly climates, similar marine effects can be achieved with cold hardy species of succulents, such as sedums, sempervivums, various ice plants, small Mammilaria cactus, and cholla cactus (Opuntia). Non-hardy species can be added for the summer or incorporated in nearby container plantings.

A red-leafed Kalanchoe adds a bright splash of color to the mix of blues (Senecio and Euphorbia) and the grays and tans of Dyckia Mammillaria, and other succulents

A red-leafed Kalanchoe adds a bright splash of color to the mix of blues (Senecio and Euphorbia) and the grays and tans of Dyckia Mammillaria, and other succulents

A Well-drained Underseas Garden

Succulent gardens generally require well-drained soils. Throughout QBG’s Undersea Garden, a cactus and succulent soil mix was used, although a few plants like the octopus mimics (Dyckia marnier-lapostollei) require more water and were planted with additional bark mixed into the planting medium.

In order to depict the structure of a coral reef, volcanic rocks of varied sizes and colors were used. Many were selected with appropriate crevices, cavities, and small holes. The rock colors ranged from browns and tans to reds and even purples. In a normal landscape, such an array of colors might not work, but it has proven to be an effective combination for evoking a coral reef. Furthermore, the rocks were placed upright, contrary to conventional naturalistic rock placements, which are more horizontal. The elevated coral outcrops are connected by expanses of dark volcanic gravel and light-colored sand.

A crested cactus (Mammillaria matudae) mimics brain coral

A crested cactus (Mammillaria matudae) mimics brain coral

Some of the most dazzling inhabitants of true coral reefs are the shoals of multicolored fish. Few plants, if any, look like fish. Neither are there plants that look like crabs or clams (there are, admittedly, some fundamental differences in morphology between plants and animals). Here in the Undersea Garden, toy coral reef fish, crabs, and a solitary octopus were strategically placed in the landscape, to the delight of small children. A variety of sea shells were strewn about the “ocean floor,” along with an obligatory rusty anchor and other nautical paraphernalia.

There are unlimited opportunities to embellish an underseas garden with further ornamentation, ranging from natural oceanic objects (eg, giant clamshells) to sophisticated garden art. There is even the temptation to add some imaginative elements of garden humor—mermaids or Caribbean pirate treasure, for instance.

The Undersea Garden is an imaginative exploration of both the underwater world and of the remarkable diversity of succulent plants from some of the world’s driest habitats. Only 1,300 square feet in extent, it has quickly become one of the most popular features at Quail Botanical Gardens.