Saguaro Cactus: Facts, Adaptation & How To Grow


Saguaro Cactus (Carnegiea gintantea) is native to the state of Sonora in Mexico and some parts of California and Arizona in the United States. Saguaros have barrel-shaped bodies with peripheral stems referred to as arms. In its natural environment, the Saguaro can reach maximum heights of 60 feet (18.3m). Saguaros have a relatively long lifespan, often exceeding 160 years.

The Saguaro can absorb and store considerable amounts of rainwater, visibly bulging in the process, while slowly using the stored water as needed. This characteristic enables the saguaro cactus to survive during periods of drought. In May, the plant produces three-inch wide, creamy white blossoms with yellow stamens that grow in clusters on the southeastern side of the stem tip. After flowering, the plant produces a reddish-green, three-inch, oval, edible fruit which has red pulp and black seeds.

Facts About Saguaro Cactus

  1. The Botanical name for saguaro cactus is Carnegiea gigantea. It was named in honor of industrialist Andrew Carnegie, whose Carnegie Institution established the first Desert Botanical Laboratory in Tucson, Arizona in 1903.
  2. Saguaros are found exclusively in the Sonoran Desert of extreme Southeastern California, Southern Arizona and northwestern Mexico.
  3. The saguaro cactus is the largest cactus in United States and will normally reach heights of between 15 and 60 feet tall.
  4. The saguaro cactus is composed of a tall, thick, fluted, columnar stem, 18 t0 24 inches in diameter, often with several large arms curving upwards.
  5. Some saguaros have dozens of arms bending upward whereas others never produce a single arm.
  6. The skin of saguaro is smooth and waxy and the trunks and stems have two inch spines clustered on their ribs.
  7. The saguaro cactus grows as a column at a very slow rate, with all growth occurring at the tip or top of the cactus. It perhaps grows 1 inch in height after 1 or 2 years.
  8. The Saguaro cactus has a lifespan of between 100-200 years and can weigh between 2 to 3 tons at maturity.
  9. A saguaro begins to flower when at around the age of 35 years and produces it first arm when at 50 years of age.
  10. Saguaro cactus will produce flowers during late spring into early summer. Typically, the flowering occurs between April and June.
  11. The flowers of saguaro are milky white in color. A dense group of yellow stamens forms a circle at the top of the tube.
  12. The saguaro flowers have more stamens per flower than any other desert cactus. The flowers emit a sweet nectar which attracts birds, bats and insects.
  13. Saguaro obtains most of its moisture during the summer rainy season.
  14. The saguaro produces a three inch, oval green fruits which ripen when the fall rainy season is near. Usually the fruits split open to expose the bright-red, meaty flesh.
  15. Saguaro cactus produce hundreds of tiny black seeds the size of a pinhead in one bright red fruit and as many as 40 million seeds in a lifetime, but perhaps only one will actually survive to become a fully grown cactus.
  16. After the saguaro dies its woody ribs can be used to build fences and parts of furniture.
  17. Saguaros are usually very heavy when they are fully hydrated and can weigh more than 3 tons when fully hydrated.
  18. Despite its enormous weight and height, the saguaro cactus has a relatively shallow tap root system; about 3 feet deep down the soil with several smaller radially emanating roots from the base. These roots wrap around rocks hence providing anchorage from wind and other factors.
  19. The saguaro can only be fertilized by cross-pollination (pollen grains coming from a different cactus).
  20. The best method of growing saguaro is through seed propagation. The seeds normally require high temperatures to germinate.

Adaptations Of Saguaro Cactus

The Saguaro cactus just like other cactus has numerous characteristics which enables it to survive in its native desert habitat. Some of these characteristics include:

  • The saguaro is consists of a taproot system which runs about three feet into the ground and is used to collect deep ground water and nutrients as well as help anchor the saguaro.
  • The saguaro root system is also made up of shallow, lateral roots which extend far from the growing plant. These roots are used to collect moisture and rainfall water.
  • The skin of the saguaro cactus is covered with a thick waxy coating that waterproofs the plant and reduces water lose to the air through transpiration.
  • The trunks and stems of Saguaro cactus have two inch spines clustered on their ribs. The spines protect it from animals that would most likely eat its fleshy stem or use it as a water source.
  • The interior of Saguaro stem is majorly made up of large parenchyma cells which stores large amount of water for photosynthesis and protection against heat extremes.
  • The leaves of the saguaro have been modified into spines and cannot therefore perform photosynthesis, in this regard; the stem is adapted to performing photosynthesis.

How To Grow Saguaro Cactus In Pots From Seeds

Saguaro cactus is easily grow in pots and doesn’t require much maintenance.  Just like other types of cactus, Saguaro requires extremely loose, loamy and coarse soil that is free of organic fertilizers like compost or manure. Here is what you need to do in as far as growing and caring for saguaro cactus is concerned.

  • Choose a relatively large or medium pot/planter with drainage holes on it. Don’t choose containers that are too narrow, tall or deep. Drainage holes provide an exit route that allows excess moisture to seep out after the plant has been watered. Without drainage holes, the soil inside the container becomes waterlogged and this can make the cactus susceptible to root and stem rot as well as fungal and bacterial infections.
  • Combine equal portion of ground fir bark and peat moss or coconut coir in a bucket to form a potting mix. Then, mix the potting mix with the coarse builder’s. For the sand, you can substitute with pumice, perlite or vermiculite.
  • Mix everything well and make sure there are no soil lumps until the soil blends well.
  • Make several holes in the soil and place the saguaro seeds in the holes and lightly pinch the soil closed over them. Sprinkle water over the soil so that the seeds do not dry out.
  • Cover the planter/pot tightly with a plastic wrap or paper. Make sure to poke at least two holes in the plastic wrap to aerate the soil.
  • Place the pot/planter in a room or warmer location that is well lit, but not in direct sunlight.
  • After between 5 to 6 weeks, Reddish-green saguaro seedling begins to emerge from the tiny black seed. During this time, remove the plastic wrap and keep the saguaro seedlings moist by watering them at least thrice per month.

Summary Of The Plant Profile

Botanical NameCarnegiea gigantea
Common NameSaguaros
Light RequirementFull Sun
Soil TypeSandy or loamy
Soil PHNeutral
Root SystemVery Shallow
Ultimate HeightUp to 18m (60ft)
Ultimate SpreadUp to 5m
LifespanBetween 150-200 years
NativeSoutheastern Arizona & Northwestern Mexico
FloweringAfter 35 years
Bloom TimeApril and June
Flower ColorCreamy White
Interior of the StemFilled with sponge-like tissue
Fruits ColorRuby red
Fruit size6 to 10 cm
SeedsSmall and short-lived
Growth RateSlow
Pollen Grains ProductionLarge quantities
HabitatDesert Slopes and flats
Weight When Fully HydratedBetween 3200-4800 pounds
Common DiseasesRoot Rot, Bacterial necrosis