Tuesday, August 21, 2012

Sterile Plants: All-season Bloomers

A lot of the plants in my garden this year have something in common: they cannot bear young. 

Lobularia 'Blushing Princess': no seeds but lots of syrphid flies!

One might say it’s a triploid revolution!

But let’s start at the beginning.
The flower exists for one purpose—to attract pollinators. Once its powdery pollen is transported by bee, moth, beetle, or some other vehicle to the ovule of another flower, its function is finished. Seeds form. Eventually, baby plants germinate. So as the summer wears on and flowers turn to seeds, the plant has less and less incentive to make more flowers. Unless, of course, some manipulative gardener beheads the dying blooms. 

But what tedium, what fussiness! 
Cleome 'Seniorita Blanca' in late August

How fortunate for the lover of all-season color that plant breeders have stepped in. What! you say? Breeders “play god” and manipulate plants just so we can enjoy cleome that doesn’t become a spidery tower of swaying seedpods, and sweet alyssum that doesn’t get ugly in August? What’s next—tomatoes that don’t rot?  

Well, maybe … but that’s another story.

Back to the point – how, and why, does a scientist make a flower that will not fulfill its function? 

The answer to how is varied and complicated. Why is a little more straightforward. Take lantana, a beautiful flower that is benign in cold-winter regions like Pennsylvania, but a menace in the south. In fact, it’s one of the top 10 weedy species of the world. And its chromosomes are to blame.

Lantana 'Luscious Berry Blend' makes no seeds.
Many organisms (us, for instance) are diploids, meaning we have two complete sets of chromosomes, one from mom and one from dad. Plants often have multiple sets. Lantana can have two, three, four, five, or even six sets of chromosomes. Those with even numbers of sets are fertile (sometimes very fertile), and those with odd numbers are largely sterile. Combine a plant with two sets (a diploid) with one with four (a tetraploid) and the result is: ta da, a sterile triploid! It will start to form seeds but they will never become blackberry-like and fertile. 

Selling sterile plants will not undo the damage caused by the rude tetraploids let loose in warm climates, but it will at least allow gardeners to plant lantana with a clear conscience. And non-seedmaking plants bloom and bloom. Yes, I am aware that lantana berries are ornamental. This, I suspect, is a rationalization that will be handily tossed when the juicy fruits are absent. 
Hibiscus 'Blue Chiffon': blooming itself silly.

Other sterile or mostly sterile plants in my garden are ‘Lilac Chip’ buddleia, ‘Seniorita Blanca’ cleome, ‘Blushing Princess’ sweet alyssum, ‘Diana’ rose-of Sharon (my ‘Blue Chiffon’ rose-of-Sharon is not a triploid but is blooming itself silly nonetheless). Some of my seed-free plants are triploids, others are the sterile hybrids of two different species. 

Burning bush triploids will be available in four to five years, says breeder Yi Li of the University of Connecticut. And other good versions of bad troublemakers are on the way. Scientists are working on making impotent Norway maples, barberries, privets, and callery pears so that they won’t wreak havoc on the few natural areas that have not yet been compromised. 

From the BIG perspective, creating a cleome or sweet alyssum that blooms all summer seems a monumentally trivial achievement. And the self-serving aspect—no self-sown seedlings means more sales—is not lost on me. Scientists working on safe-to-plant versions of invasive plants are providing gardeners with guilt-free alternatives. A sterile burning bush, however, will do little to save the earth. 

But in the evenings, when I revel in the exponential multiplication of the blooms (that still, by the way, attract scores of pollinators), and enjoy the sweet scents, I am happy that breeders tinker with odd-numbered ploidy.  

Now if they would just start working on squash bugs ….

Tuesday, August 7, 2012

Rock Art

“Make art,” I told the eight student interns from Isles of Trenton. The instruction was greeted with quizzical looks all around. 

The Problem was the pile of large rocks that had been dumped onto a concrete pad 12 years ago during the digging of wells for a geothermal heating system, with no thought about how they might, or might not, be used in the future. Dried leaves collected in the cracks and, over the years, turned to compost. Poison ivy and enchanter’s nightshade (a plant that is not at all as pretty as its name) had taken hold in the crevices until the rocks were completely concealed during the summer months. With roots securely anchored by the weight of the unruly pile, the interlopers were resistant to my frequent attempts at manual control.

I envisioned something neat. Maintainable.

Morven is, after all, a historic property. Visitors visit. Students of history roam about. Watercolor artists sit in front of easels and paint beautiful scenes.  

The opportunity for making art out of rocks and brawn arose in the last day of the tenth year of a collaboration between Morven, a museum and garden in prosperous Princeton, and YouthBuild, an organization that helps young men and women from the ‘hood rise above the expectations the world holds for them. The cultural divide cannot be overstated.

What happened next was pure magic. When asked to explain the remarkable construction that emerged after an hour of creative play, one of the artists remarked, “You can’t really explain it. That’s what makes it art.”
Isles YouthBuild Institute 2012

Even more thrilling than the individual components of the piece—the blocky frames, the found images that had been created by centuries of deposition of weathered rock and detritus, the round rocks dramatically perched—was the collective realization that “Art” is not out of reach. It can be grabbed at will. We need only give ourselves permission to “make art,” and magic happens.

Morven staff members wandered back in ones and twos to view the wonder. Visitors admired it. The creators posed beside their construction for photos, and added their signatures on a piece of slate with liquid chalk. The pride was communal, and it was individual. “IYI 2012” (Isles YouthBuild Institute 2012), reads the top line on the rock sign.

The group had completed many fine tasks during their five weeks on the job. They had edged and mulched garden beds, planted trees and flowers, pruned overgrown hedges, and reworked a hazardous stone walkway. As they showed off these accomplishments there was obvious pride of craftsmanship. None of these, however, came close to establishing the level of cross-cultural bonding created by the rock art.   

Make Art Not War (or something like that ...)
The question raised by this experience is this: If it is so maddeningly simple to bridge a cultural divide by making collective art, how can we bring more creative play into our frenetic days? 

We must give ourselves permission to play, to discover, to create. The creative spirit speaks a universal language, which in turn creates a universal bond. It cannot be expressed in words.

“That’s what makes it art.”