Echinocactus platyacanthus Biznaga Gigante My cactus plants

Family: Cactaceae (Cactus Family)

Scientific name: Echinocactus platyacanthus Link et Otto 1827

Common name: Biznaga Gigante

Etymology: Echinocactus: generic name derives from the Latin : echino = "hedgehog" andcactus, which means that is a cactus shaped like a hedgehog .

The species name "platyacanthus" comes from the Greek for "with wide thorns"

Origin: ranges over much of northeast and central Mexico.

Common Names: Biznaga Gigante, Biznaga de Dulce; Giant Viznaga & Large Barrel

Synonyms: Echinocactus ingens; Echinocactus karwinskii; Echinocactus helophorus; Echinocactus visnaga; Echinocactus palmeri

This is the largest of all barrel cacti, it is grey-blue and nice when small, but areoles merge and forms a continuous line when it became large.

Description: it is a slowly growing massive barrel cactus usually solitary that grows huge in habitat ( up to 2,5 m tall , 1,5 m wide). It could live more than a hundred years. The stem is grey-blue ± tuberculate and nice when small, whilst large plants are heavily ribbed with numerous areoles forming a continuous line. Spines are black. 
Flowers:  from end of spring to summer only on larger mature specimens receiving enough full sun. They  are diurnal,  vivid yellow. 
Mature specimens often have a somewhat sway-backed, saddle-shaped apex, densely covered in white wool, where their flowers emerge.

Tubercles: Note: The juvenile Echinocactus look very different from the mature specimens. In fact like the other Echinocactus and Ferocactus seedlings, the rib structure is not yet apparent, and they have pronounced tubercles.    
Older specimens take on an oblong shape with age and can dominate a landscape because of their large size and impressive bulk. They also tend to lean to the south or southwest so that the spines can better protect the body of the plant from the harsh desert sun. In fact, desert travellers can use the plant as a compass.

Spines: The spines change over the years, there are long, short, flat, reddish and then darken with age

Radial spines: Radial spines 7 to 11 3 to 5 cm long.

Central spine(s): 4 central spines, sometimes forming a cross, of different sizes each curved even some 5-12 cm long

Flowers:  Flowers yellow numerous, emerging from a yellowish wool at the tip of the stem, opening quite extensive, yellow 4 to 7 cm in diameter.

Bloom time:. Mid Spring, Late Spring/Early Summer

Sun Exposure: Full sun.

Watering Needs: Regular watering in summer, dry in winter

Cultivation: Frost tender but resistant to -4°C for short periods; Cold hardiness increases with improved drainage, so keep plants as dry as possible in winter. They grow best in well-drained soil and a position in full sun, which will help to maintain the lustre of the spines and longevity of the flowers. Provide the plant with extremely well-drained soils, as the plant are subject to crown and soft rot if it remains too moist. Besides, it performs wonderfully in containers, Container media should be coarse as well. Young plants are prone to mealy bugand red spider mite.

Economical uses: This plants is used to prepare a traditional candy, the pith is boiled with sugar to produce a popular sweet called “dulce de biznaga” or "acitrón". In this case the overcollection of wild plant for making cactus candy is the major threat to the survival of this species.
This plants were also used by indigenous peoples of Mexico in many manner, for example the woolly hairs this plant produces have been used as filling fibers and weaving.

Notes: The Huichol people called "Aikutsi" used it for ceremonies as it contains alkaloids.