Pachycereus marginatus

Pachycereus marginatus

Scientific Name

Pachycereus marginatus (DC.) Britton & Rose

Common Names

Mexican Fence Post Cactus, Fence Post Cactus, Central Mexico Pipe Organ, Organ Pipe Cactus, Mexican Organ Pipe Cactus, Organ Pipe, Organo


Cereus marginatus, Cereus gemmatus, Lemaireocereus marginatus, Lophocereus marginatus, Marginatocereus marginatus, Stenocereus marginatus

Scientific Classification

Family: Cactaceae
Subfamily: Cactoideae
Tribe: Pachycereeae
Genus: Pachycereus


Pachycereus marginatus is a cactus with columnar trunks that slowly grow up to 12 feet (3.7 m) tall. The stems are up to 4 inches (10 cm) in diameter and have 5 to 7 ribs, one central spine, and 5 to 9 radials, all slightly yellowish. Flowers are pink to greenish and up to 1.6 inches (4 cm) long. The spiny fruits are yellowish to reddish, 1.6 inches (4 cm) in diameter, with many black seeds.

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USDA hardiness zone 9b to 11b: from 25 °F (−3.9 °C) to 50 °F (+10 °C).

How to Grow and Care

Like most other plants that can grow to staggering size, Pachycereus cacti grow extraordinarily slowly throughout hundreds of years. They require virtually zero assistance on your end, provided they are raised in a desert environment.

These extraordinarily, low-maintenance plants can grow untouched for decades, so there is not much you need to worry about. They must receive adequate sun and heat and be careful around their spines. If grown in containers, make sure that they are being repotted and that their soil isn't too moist. Other than that, these plants are about as hands-off and straightforward as it gets.

Like most cacti and succulents, these plants propagate by cuttings. Sever a branch and replant in well-drained soil. Make sure to stand the cactus up in an empty container to let its ends heal off before you replant it; this will keep its stems shaped right, and cacti with dried ends form roots more easily after planting. See more at How to Grow and Care for Pachycereus.


Pachycereus marginatus is native to Central Mexico.


  • Pachycereus marginatus f. cristata


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Pachycereus marginatus - garden

Origin and Habitat: Central Mexico (San Luis Potosí, Querétaro, Guanajuato, Mexico D.F Hidalgo, Oaxaca). Cuttings from Stenocereus marginatus are widely used as barriers, often becoming living fences, and it is so widely used throughout Mexico that its geographic origin is uncertain.

  • Pachycereus marginatus (DC.) Britton & Rose
    • Cereus marginatus DC.
    • Lemaireocereus marginatus (DC.) A.Berger
    • Lophocereus marginatus (DC.) S.Arias & Terrazas
    • Marginatocereus marginatus (DC.) Backeb.
    • Stenocereus marginatus (DC.) A.Berger & Buxb.

Description: Upright and clumping, stiff and imposing, columnar cactus with unbranched stems from the base. In the wild it grows up to 15 m in height, cultivated, it is columnar, up to 4 m tall or more.
Stems: Erected, basally branching to 5-10(-20) cm thick, dark green. The epidermis surface is slightly rough to the feel, like sandpaper.
Ribs: 5 to 7 (or more), 2 cm high.
Areoles: White, glandular, mostly about 1cm apart, confluent forming an uninterrupted longitudinal line.
Spines: 1 yellowish central spine up to 1 cm long. 5-9(14) short radials. The spines are longer in the juvenile specimens, while are very short in the mature branches.
Flowers: Pink to greenish, up to 2 in each areole, 3 to 4 cm inches long.
Blooming season: Spring.
Fruit: Spiny, yellowish to reddish, up to 4 cm in diameter, and rather dry in late spring to early summer. The many seeds are black.

Subspecies, varieties, forms and cultivars of plants belonging to the Pachycereus marginatus group

Bibliography: Major references and further lectures
1) Forest & Kim Starr “Pachycereus marginatus (Central Mexico organ pipe). Plants of Hawaii. . Downloaded on 20 August 2014.
2) James Cullen, Sabina G. Knees, H. Suzanne Cubey “The European Garden Flora Flowering Plants: A Manual for the Identification of Plants Cultivated in Europe, Both Out-of-Doors and Under Glass” Cambridge University Press, 11/Aug/2011
3) Curt Backeberg “Die Cactaceae: Handbuch der Kakteenkunde” Vol. 4 G. Fischer, 1960
4) Hans Hecht “BLV-Handbuch der Kakteen” BLV, 1991
5) David Hunt, Nigel Taylor “The New Cactus Lexicon” DH Books, 2006
6) Erik Haustein “Der Kosmos-Kakteenführer: Bestimmung, Pflege, Vermehrung. Über 490 Kakteenarte” Franckh-Kosmos, 1998
7) Sara Oldfield “Cactus and succulent plants: status survey and conservation action plan” IUCN, 1997

- This is a very neat columnar cactus, sometimes branching with small spines along linear rows up and down the plant. Photo by: Valentino Vallicelli
Pachycereus marginatus Photo by: Cactus Art
Thorns at Kula Ace Hardware and Nursery, Maui, Hawaii (USA). September 06, 2007. Photo by: Forest Starr & Kim Starr
Pachycereus marginatus Photo by: Valentino Vallicelli
Pachycereus marginatus Photo by: Valentino Vallicelli
Top and thorns at Kula Ace Hardware and Nursery, Maui, Hawaii (USA). September 06, 2007. Photo by: Forest Starr & Kim Starr
Pachycereus marginatus Photo by: Valentino Vallicelli
Pachycereus marginatus Photo by: Cactus Art

Cultivation and Propagation: It is easy to grow but not very cold hardy (Resistant as low as -4°C for a short time).
Sun Exposure: Outside full sun, inside needs bright light, and some direct sun.. Need a fertile, well drained soil mix. In summer water the plants well and allow them to dry before watering again. During winter month, put them in a cool luminous place and encourage them to enter winter dormancy by withholding water and fertiliser over the winter as they will etiolate, or become thin, due to lower levels of light. They are susceptible to fungal diseases if overwatered, but are not nearly as sensitive as many other cacti, especially in warm weather. If kept damp through cold periods, they will invariably suffer.
Plants grown outdoor in the ground produces exceptional amounts of growth, often more than 1 m each year if kept well fed and watered throughout the warmest months, particularly if it has been acclimatised to accept full sun.
Propagation: Cutting or from seed. The seeds are quite easy to germinate and grow. Their main requirements consist of high humidity levels, free-draining soil mix, and enough water, light, and nutrition.

Defensive barriers: The stems are exceptionally straight, in Mexico, where it is extensively cultivated, they are often used to make live fences (a wall of these is hard to get through and/or see through). It is also useful to built effective wind break barrier.
Landscape use: Specimen or focal point in the landscape, desert landscape design themes, similar to Organ Pipe cactus, but with a cleaner, sleek appearance. Not for use in small spaces. There are many cultivated varieties.

Mexican Fence Post

Mexican Fence Post are stately, attractive and a must-have for anyone that loves cactus! Native to Mexico, you can’t help but notice this fast-growing cactus with dark green foliage and columnar trunks – it’s a favorite used in many landscapes that fit the southwestern theme. That said, we love to plant Pachycereus marginatus with any landscape theme! The seasonal pink blooms contrast beautifully, adding even more stunning color to their surroundings! Feel free to grow in containers or use them as a bold and dramatic accent in your landscape!

Mexican Fence Post are heat tolerant and get extra bonus points for being Verticillium Wilt resistant. They love to grow with full sun and partial sun exposures, and once established are drought tolerant with low to moderate watering needs. It’s an evergreen that looks great all year and is very low maintenance, in fact, they can basically grow untouched for many years, so it really is one of the best hands-off plants you can find!

We love to plant them to create a tall living fence, where they can be used as a privacy hedge to screen against unwanted views or to simply create an unforgettable sight in your landscape! They are also a great choice to plant around swimming pools or for use as a patio plant. If you love the sight of hummingbirds, you’ll be happy to know that during the spring and summer flowering season, hummingbirds are sure to pay a visit to your garden!

If you want to the full benefit of Pachycereus marginatus, we recommend buying as big as you can! We have been growing Mexican Fence Post cacti for over 20 years, from our own private stock of premium quality specimens! This means we are able to offer the best-quality, bigger cacti that you will not find anywhere else! Let our professionals do all of the hard work for you – from the design to the delivery and installation!

  • A must-have for anyone that loves cactus!
  • Dark green foliage and columnar trunks
  • Evergreen
  • One of the best hands-off plants you can find!
  • Can be used as a privacy hedge or living fence
  • Attracts hummingbirds