Skip to Content

Torch Cactus (Trichocereus Spachianus)

Torch Cactus also known by its scientific name Trichocereus spachianus, is an invasive plant species mainly found in Argentina in South America.

It is a spiny succulent plant with erect green multi-stems that branch profusely at the base. This cactus species can grow up to 2 meters tall and reproduce from the base. 

In the savannah, the plant grows under trees, barring shade for both domestic and wild animals. It can also injure grazing animals. 

Scientific Classification

  • Kingdom: Plantae
  • Family: Cactaceae
  • Subfamily: Cactoideae
  • Tribe: Trichocereeae
  • Order: Caryophyllales
  • Genus: Echinopsis
  • Species: Trichocereus spachianus
  • Common Names: Echinopsis spachiana, Golden Torch Cereus, and White Torch Cactus

Nativity and Distribution

Torch cactus is native to Argentina in South America. Other areas where the plant is found include:

  • South America: 
    • Northern Chile
    • Bolivia
    • Ecuador
    • Peru
  • South Africa: 
    • Eastern Cape
    • Northern Cape
    • Western Cape
    • Free State
  • Australia

Physical Characteristics

Torch Cactus has bluish-green columnar stems and white flowers
Torch Cactus has bluish-green columnar stems and white flowers. Image: Facebook/jturnbull
  • Leaves: Trichocereus spachianus does not have true leaves. It has areoles which are modified structures from which spines, flowers, and new shoots emerge.
  • Fruits: After flowering, the plant produces small, round fruits that are red when mature and covered in hair-like spines.
  • Stems: The stem is columnar, ribbed, segmented, upright, and varies in color from green to bluish-green to a slight yellow hue. 
  • At the stem surface are vertical ribs with each rib dotted by areoles from which the spines and flowers emerge.
  • Flowers: Trichocereus spachianus produces white showy flowers up to 20 cm long. They appear in spring and are mostly seen at night.
  • Roots: Torch cactus has a fibrous root system. The roots spread out near the surface of the soil. They are sensitive to oxygen deficiency. If the roots are in soil that is poorly permeable in air and water, root rot can occur.
READ ALSO:  7 plants that look like chamomile

The plant has a cylindrical green body with 1-2 cm long golden spines, a columnar habit, and the branches ascend parallel to the main stem.

The areoles are covered with yellow wool that turns gray as the plant ages. Initially, the straight spines are a reddish yellow, later fading to gray as they age.

Plant Adaptation

Torch cactus is a frost-resistant plant though temperatures should not go below 5 to 10 degrees Celsius. If the seed is grown in soil with too much humus it tends to rot. 

The plant grows in partial shade, though it can also tolerate full sun. It needs to reach a certain size before it can flower, and it tends to produce very large flowers.

It reduces its water requirement as an adaptation and as a succulent plant, Trichocereus spachianus is adapted to its environment in the following ways:

  • It contains sunken stomata to reduce the loss of water.
  • It covers the ground to reduce evaporation from the ground.
  • The small leaves do not attain high temperatures during the day like large leaves.
  • It has thick stems to store water.
  • Its leaves are waxy to prevent evapotranspiration.
  • It can handle no water in winter.

Reproduction, Dispersal, and Life Cycle

The golden-spiked Torch Cactus can grow up to 2 meters
The golden-spiked Torch Cactus can grow up to 2 meters. Image:fairdinkumseeds
  • Life cycle: Trichocereus spachianus is a perennial plant that can live for many years in various arid environments. The life cycle starts with the flower which has to be pollinated by insects to produce seeds.
  • Bats, bees, and hummingbirds are necessary for pollination. These animals obtain food from the cactus, which in turn pollinates the cactus.
  • Seeds: Torch cactus produces black seeds which can be found in the green hairy fruits and can be used for propagation.
  • Dispersal: Animals such as coyotes and tortoises, eat the plant’s fruit and then disperse the seed in their feces.
  • Climate: This plant can take in the heat but grows best at day temperatures of 21-38 degrees centigrade and cooler night temperatures of 10-21 degrees centigrade.
READ ALSO:  Garden Weeds with Red Stems and Green Leaves

Uses

  • Fencing: The plant can be utilized as a hedge for fencing purposes due to its tough nature.
  • Ornamental purposes: This cactus can be grown in small desert gardens grown in association with other xerophytes for ornamental value.
  • Grafting stock: Trichocereus spachianus can be used as a grafting stock for other cactus species.

Control

Effective methods of controlling Trichocereus spachianus include:

Natural methods

    You can dig out the cacti species. However, you need to be careful as the plant’s seeds may spread. In addition, you need to remove the plant’s entire roots to prevent it from regrowing.

    Biological control

      Biological control involves identifying the plant’s natural enemies such as the Galling Mealybug, Dactylopius opuntiae ‘stricta’, and various species of cochineal insects to control the cactus.

      Herbicides

        Herbicides are most effective at the onset of a growing season or when the Torch cactus is blooming and the temperatures fall below 90 degrees Fahrenheit.

        Picloram is an herbicide used to control cacti species. It is important to follow label directions for the proper application rates and to determine the most effective season for applications. 

        Herbicides formulated with Picloram work best on spot applications of cactus plants rather than as a broad-area spray. Picloram can penetrate deep enough into the soil to contaminate groundwater.

        READ ALSO:  20 types of grass used in landscaping

        To kill cacti, hexazinone can be applied at the base. It kills the cactus slowly by interfering with photosynthesis.

        Hexazinone is also sold mixed with other herbicides and should not be sprayed in a broad area but used on individual plants. 

        After applying herbicides that are formulated with hexazinone, water the area to ensure the herbicide works as it should.

        Related Plants