Gardening 101: Totem Pole Cactus

Senita Cactus, Lophocereus schottii v. monstrosus: “Totem Pole Cactus”

If your idea of a cactus is a hostile, squatty little plant bristling with dangerous spines and gathering dust on someone’s windowsill, then you really should broaden your knowledge of this fascinating desert flora.  For instance, you could investigate the genus Lophocereus (also known as Pachycereus). There are approximately a dozen species and they really couldn’t be more different from the cartoon version of a cactus.  They tend to be columnar, tall (up to 82 feet in one spectacular case), and resemble trees or large shrubs with branches reaching upward from the base at ground level.  In the wild they grow in colonies in dry, gravelly soils.

Above: Photograph by Laure Joliet. Lophocereus in the collection at the Huntington Botanical Gardens in A Magical Glasshouse Garden in Pasadena.

One of the most unusual varieties of the genus is Lophocereus schottii var. monstrosus.  Where the species,  known as the Senita cactus,  produces rows of dark spines on its very regular, fleshy ribs, the monstrosus is completely spineless.  In fact it resembles something that might have once been a cactus but has been sanded clean of all sharp protuberances and left to resemble a bumpy green rolling pin or foot massager.  Also known as the Totem Pole Cactus, the monstrosus is the result of a naturally occurring mutation and is native to a small area on the Baja California Peninsula.  It was apparently discovered off a dirt road in 1931 by the intrepid American plant explorer Howard Gates who came upon a group of the odd looking plants near Playa El Arco.

Above: Photograph by Raffi Kojian via Wikimedia.

Cheat Sheet

• The monstrose form of Lophocereus schottii usually does not flower or seed but it can be propagated easily by taking cuttings from the top of the stem or from a branch.
• If your climate is mild enough to allow you to grow Lophocereus outside, it is a good idea to plant your cactus on a sunny slope, which will ensure good drainage.
• Totem Pole Cactus grown outside can take years to reach its maximum height of 10 to 12 feet, but it is an easy plant to grow: unbothered by insect pests and disease as long as it is not over-watered.

Keep It Alive

• Monstrosus can be grown outdoors in zones 9 to 11.  Gardeners in cooler climates should plant their specimens in clay pots in gritty cactus soil and take them inside when temperatures fall below 50 degrees Fahrenheit.

• Indoors, make sure the totem pole cactus is placed where it will receive full, direct sunlight all day, preferably in a south-facing window.

• Water the cactus only when the soil completely dries out. Make sure to empty the saucer under the pot so your cactus will not be sitting in water. That can lead to root rot, a fatal malady.

Above: Photograph by Raffi Kojian via Wikimedia.

Totem Pole cactus works well in xeriscapes and its tall shape can provide attractive vertical interest. The fact that it is thornless makes it suitable for high traffic areas such as paths or steps.  It is a good companion plant for succulents which have similar cultivation requirements (a full day of bright sun, freely draining soil) such as agaves and euphorbias. Traditional organic mulches which retain moisture in the soil can be harmful to cacti. Grit or pebbles or crushed stone can be used as a top dressing but should not be allowed to touch the plant.

For more low-water plants that look lovely in a landscape, see:

• Gardening 101: Echeveria.
• Required Reading: Ruth Bancroft’s Bold Dry Garden.
• Designer Visit: An Indoor-Outdoor LA Garden by Judy Kameon.

.