Louis Raymond experiments in his own gardens like

a mad scientist, searching out plants that most people have

never seen before & figuring out how to make them perform.- The Boston Globe

…Louis Raymond ensures that trees can grow in Brooklyn…

or just about any other place where concrete consumes

the dirt and skyscrapers shield the sunshine.- USA Today

 
 

NEW Trips to Take!

Myrtle's easy when the conditions are right.

 
 
 
 

NEW Plants to Try!

Louis tries to capture the exact words to describe the fleeting but deep pleasures to be found in these Summer-into-Autumn incredibles.

 
 
 
 

New Gardening to Do!

Allergic to bees? You can still have an exciting garden, full of flowers and color and wildlife.

 
 
 
 

Plant Profiles

Today in the Garden of a Lifetime: 'Claude Barr' Prickly Pear Cactus

Opuntia-humifusa-Claude-Barr-flower-070714-640 

 

A cactus in bloom: So much excitement. In vivid coloring, bounty of pollen and nectar, and sheer size, the flowers' pull is nearly gravitational. Thank goodness: In the desert, plants are few and far between. You've got to mount a high-wattage performance if you want your flowers to be noticed by pollinators.

 

Opuntia-humifusa-Claude-Barr-flower-closeup-070714-640

 

A more serious drama is being played out at ground level: Death and life; death that leads to life; sacrifice of the individual for the community; step-by-step progress to the larger goal. This is a prickly pear cactus, Opuntia humifusa 'Claude Barr'. In Summer, the pads are creeping and even cascading. They are turgid with water and, as far as possible, stand erect.

 

In the Winter, the pads reduce their water content sufficiently so that, even in severe climates, they don't freeze. (With good drainage, you can grow this cactus from Newfoundland to Florida.) Their reduced water content causes the pads to collapse, looking like they've fainted flat-out on the ground. The Winter look of the colony—dead flat, like horticultural road-kill—creates the impression of grim, whatever-it-takes survival.

 

But a few months of cold, full-body contact with the ground is more than a desperate accommodation with brutal cold. After a long Winter, flattened by repeated snows, the limp pads have become a veneer atop the soil surface. What looks like defeat is, rather, the essential strategy to increase the colony.

 

The little dark bumps that dot the surface of the pad are specialized structures known as areoles. They function like stem cells do in animals, in that they are capable of producing anything that serves the organism's needs. For a cactus, this means flowers, spines, roots, and pads. Pads that have become pressed against the soil surface can send out roots from each areole on their bottom surfaces—and, so, provide water and nutrients to produce the maximum number of new pads from their uppers. In the picture below, you can see one of last season's pads that, over the Winter, became fully prostrated across the soil surface. Two vigorous new pads have emerged from its upper surface, as well as, at the right, what seems to be a clump of red juvenile spines that could be a third pad still making up its mind. Atop one of the mature pads is the flower in the top photos.

 

Opuntia-humifusa-Claude-Barr-older-prostrate-pads-resprouting-070714-640

 

This Winter, these new pads will also, as it were, fall on their swords for the good of the colony. They'll collapse and, as Winter's cold and heavy precipitation intensify and endure, become flattened to the soil (or, at least, to any older and already-prostrated pads beneath them). Come Spring, thanks to their cold-induced prostration, the crop of new pads and flowers that sprout from them will be all the more numerous. Pad by pad, year by year, the colony will extend outward.

 

Plenty of cacti aren't able to turn floppiness into triumph. Some other forms of Opuntia remain rigid and upright throughout the Winter. Although these permanently-erect forms lack Claude's ability to extend colonies outward through cold-weather "fainting," they have other solutions for getting around. Brittleness is one: Pads and even entire branches can fall off after only modest jostling. Even if only a few areoles are brought near the soil by the fall, rooting can take place.

 

Barrel cacti—typically squat and with a low center of gravity—are impervious to fainting or fragmenting. But after the brief but heavy rains that can gully-wash their habitat, their shallow roots can easily lose their footing. The entire plant falls over, to be washed downstream to a new mooring; multi-barrel colonies will likely be dashed apart by the trauma. New colonies in new places are the results.

 

By using fainting, fragmenting, or falling outright as physical aids to propagation, cacti change what at first seems like climatic catastrophes to a nearly fool-proof means of extending their colonies' range and lifespan. The technicolor reproductive strategy of their flowers seems obvious and even ho-hum by comparison.

 

Here's how to grow a larger and somewhat less hardy form of prickly pear; all forms of Opuntia humifusa can be handled the same way. Here's a form of Opuntia that remains upright and rigid through the Winter. Because 'Claude Barr' is unusually hardy and moisture-tolerant, it's even easier to establish in circumstances that might not provide the ideal of sharp drainage through the Winter.

 
 
FacebookTwitterRSS Feed

Stay in touch!

 

Sign up for twice-monthly eNews, plus notification of new posts:

 

* indicates required