Sickly Prickly

While summer visitors to JLBG often admire our extensive collection of Opuntia (prickly pear), few folks rave about them during the winter months. That’s because most prickly pears have a less attractive phase during cold weather. For a plant that’s composed of mostly water, opuntias learned to survive winter, by dramatically reducing the water content in its pads (cladodes), while increasing the osmotic pressure within the plant cells (intracellular). Some opuntias have been measured to lose up to 33% of it’s water weight in the winter months, while the osmotic pressure increases up to 16%. Interestingly, prickly pears from warmer winter locations have thicker pads, and tend to lose more water, while those opuntia species from more colder regions, like Opuntia fragilis, tend to have thinner pads, and need to lose much less water to survive even harsh winters that can drop to -50 degrees F.

At the same time that the pads lose water, abscisic acid (ABA) increases, followed by a rise in the sugar (mucopolysaccharides) content in the pads. In plants, sugars, known as cryoprotectants, are the botanical version of antifreeze. So, when your prickly pears look severely wilted like the plants below, we hope you will be able to emulate the cactus, and just chill out, knowing that if you leave them alone, they’ll be fine in spring.

Opuntia messacanta ssp. lata in winter

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