Prickly Pear Cactus Growth Stages

Pop quiz! What’s a type of cactus that you can eat? Though I’m sure there are countless technically correct answers to this bit of trivia, the one you’ll most likely be familiar with is the prickly pear cactus.

Prickly pear is a common name given to cacti in the genus Opuntia. There are nearly 200 species in the genus, all native to the Americas (some — impressively — grow as far north as Ontario, Canada). The most important species in terms of culinary use is Opuntia ficus-indica, sometimes known as the barbary fig.

In this article, I’ll explore the unique prickly pear cactus growth stages that help define this interesting desert crop.

Growing Conditions

Members of Opuntia are most readily identified by their flat, fleshy pads or leaves. The leaves are commonly covered in spines, though the number and size of these spines can vary from one species to another.

Overall, prickly pear cacti are hardy from USDA Zone 4 to Zone 11. However, O. ficus-indica grows best in Zones 9 to 12, where year-round temperatures are quite warm. Some gardeners grow prickly pears in pots and bring them indoors during the cooler months.

The active growth period typically lasts from early spring to fall. It’s perfectly normal for prickly pear pads to appear dry or even deflated during the winter months. This is a natural part of the plant’s dormancy. 

Care for prickly pear cacti the way you would almost any other succulent. Place the cactus somewhere that receives direct sunlight for at least 6 to 8 hours daily. 

Excess moisture is one of the most common problems in this and other cactus species. Use loose, sandy soil with ample drainage. Consider planting your prickly pear in a mound to encourage good drainage.

Growth Rate

These cacti are relatively slow-growing. On average, prickly pear cacti grow 3 to 6 inches taller and wider each year. 

The species O. ficus-indica grows faster than other varieties (which is probably part of why it is the most popular species for fruit production). Some specimens may grow up to 12 inches in a single year.

In addition to changes in overall size, you can track your prickly pear’s growth rate by the number of new pads it produces. A steady growth rate should produce up to 4 or 5 new places annually.

Growth Stages of Prickly Pear Cactus

Prickly pear growth doesn’t happen overnight. If you want to grow one of these cacti from the ground up, plan to wait 3 to 4 years for it to reach fruit-bearing age. But with proper care and some luck, some prickly pear cacti can live to be 80 years old!

1. Seed Germination

Though prickly pear cacti grow from seeds, germination can be pretty sporadic. Most growers opt to start new plants from cuttings instead.

The seeds need average soil temperatures around 77°F to sprout. A 4- to 5-week period of cold stratification (such as in a household fridge) may be necessary to break the seeds’ natural dormancy before planting.

With some luck, most seeds should germinate in 21 to 60 days. Yet, it’s not unheard of for germination to take up to 180 days.

2. Seedling

While adult cacti look very different from most other plant families, the seedlings are surprisingly similar! All cactus seeds start with a small root (the radicle) and a pair of embryonic leaves (the cotyledons).

Prickly pear cotyledons are thick and fleshy but look nothing like the spiny pads on mature plants. It could be another 7 to 21 days before the seedling produces its first ‘true’ leaf — spines.

Seedling
Credit image: Rob Hille by cc 3.0

3. Vegetative Growth

Once the seedling develops an ample root system and puts on a bit of healthy top growth, it will divert all its energy to getting bigger. 

Note that the pads of prickly pear cacti can photosynthesize just like ‘normal’ plant leaves (though, if you get into the nitty-gritty details, succulents photosynthesize slightly differently than other plants).

Its shallow root system can grow 15 feet or longer throughout a prickly pear’s lifetime. Cactus roots typically stay within the top 10 inches of soil, so don’t disturb the area around your prickly pear.

4. Flowering

The flowers of these cacti are quite stunning. Each flower can measure 3 inches or more across, and bright shades of pink, red, orange, and yellow are extremely common.

Most prickly pear species flower in spring and early summer. Though a single cactus can continue blooming for several weeks, each flower has an average lifespan of just one day.

prickly pear Flowering

When prickly pear cacti bloom, each flower sits atop what looks like a miniature pad. This structure, called the pericarpel, includes both modified stem tissue (visible from the exterior) and the flower’s ovary (protected by the rest of the pericarpel).

Suppose a flower takes enough viable pollen to fertilize the ovules (akin to eggs in human or animal reproduction) inside the ovary. In that case, the pericarp eventually turns into an edible fruit.

5. Pollination

Since the prickly pear is a type of fruit, the flowers must be pollinated to produce a harvest. Pollination mechanisms vary significantly from one species to another. Some need pollen from another plant, while others can pollinate their flowers.

Significantly, O. ficus-indica is self-fertile and can pollinate itself if another cactus isn’t available to provide cross-pollination.

According to a report from Pollinator Partnership, bees, ants, and wasps are most likely responsible for the bulk of cross-pollination in Opuntia species. The report also notes that birds are the primary pollinators for a handful of species concentrated in South America (and perhaps elsewhere).

Prickly pear cacti also have thigmotactic anthers — as first described by Charles Darwin. Thigmotactic anthers respond to stimuli (such as something brushing against the flower) by curling inward and depositing pollen on the stigma. 

6. Fruit Development

According to The University of Arizona, prickly pear fruit takes 90 to 180 days (3 to 6 months) to ripen. This ‘countdown’ starts only after the flowers are successfully pollinated.

Fruit Development

After the flowers fade and fall off, pollinated pericarpels will slowly swell and change color. While you might notice the original bright green color starts to fade early on, prickly pears don’t normally take on a noticeable red or purple hue until they are almost 100% ripe.

Any unpollinated pericarpels won’t develop into sweet fruit. They can, however, be cut from the cactus and used for vegetative propagation to create more plants!

When to Harvest Prickly Pear

In most regions where prickly pear cacti grow, the fruit peaks ripeness sometime in August. This period lasts only seven days before the fruit quality declines, so promptness is critical to a good harvest.

The best time to harvest prickly pears is when the skin is almost completely red — there may be a small stripe of green at the blossom end of the fruit — and has a bit of give. 

For more growing tips and advice, here’s a link to Butternut Squash Growing Stages that you may enjoy reading.

FAQ Prickly Pear Cactus Growth Stages

How often do prickly pear cacti bear fruit?

Cacti should bear fruit each year once they reach maturity. Most varieties flower and produce fruit once per year (usually in late summer). It’s sometimes possible to get multiple harvests in a year by planting several Opuntia species that flower at different times.

Citations

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Ben's horticultural interest grew when graduating from Hertfordshire University in 1997. Having contributed to numerous publications including Better Homes & Gardens, Garden Design Magazine, and The English Garden. He is also the author of Propagating Houseplants Made Easy.