Resembling large sewing pincushions, Barrel Cacti (genus Ferocactus) offer intimidating spines across a ribbed, spherical body for a home desert landscape. Although Barrel Cacti may look mundane throughout the year with their basic green bodies and variable spine colors, their flowers burst forth each year with a neon brilliance that is hard to miss. Blooming periods for the Barrel Cactus range broadly based on local environmental conditions.
Time Range
Barrel Cacti bloom during the spring and summer. The long daylight hours stimulate the cactus's body growth, as well as its reproduction. Brightly colored flowers attract bees for pollination. The resulting fruits become food for local wildlife and subsequently spread the seed throughout the area. Typically, the fall and winter months are dormant periods for the Barrel Cactus. Cactus growth halts throughout this period until spring, and long daylight hours reappear next year.
Light Factors
Blooming can be affected by too much or too little sunlight. Barrel Cacti must have full sunlight throughout the spring and summer to produce the gorgeous flowers that reside on the top of the plant, but blooming can be stunted when the plant is not properly acclimated to a sunny area. Houseplants placed outside after a shady winter can fail to bloom since they can become sunburned across their green bodies. The plant should be slowly introduced into the sunlight rather than thrust into 12 hours of constant light. In contrast, a Barrel Cactus that remains in the shade throughout the entire year does not produce a ring of flowers that resembles a crown. The cactus may not flower at all or simply produce flower buds without opening.

Water Factors
Cacti are known for their acclimation to drought conditions. Their ribs expand with water for storage and contract as the water is consumed throughout the dry period. However, a cactus that has shriveled up from lack of water does not have the strength to produce large blooms. The intricate blossoms require a lot of energy from the plant to cultivate and open. A Barrel Cactus that retains a normal amount of water from infrequent watering should be able to bloom within the typical spring and summer periods.
Soil Considerations
Although acclimating to many soil types, the Barrel Cactus depends on a well-drained and rich soil structure to produce flowers. Fertilizing with a 5-10-5 ratio mixture during the growing months will also help amend the soil for spectacular flowers. The numbers represent the percentages of nitrogen, phosphorus, and potassium in the product. The higher phosphorus amount promotes blooms over stem growth. Poor soil nutrients contribute to low blossom output, if any growth at all. Additionally, soils that waterlog the roots also contribute to root rot and blossoming problems; Barrel Cacti cannot live in wet soil conditions for very long.
Source: sfgate.com
Links
- Back to genus Ferocactus
- Succupedia: Browse succulents by Scientific Name, Common Name, Genus, Family, USDA Hardiness Zone, Origin, or cacti by Genus