The gardener's gamble

Here's a sticky one: what do horticulture and gambling have in common? 

On the surface of it, they're worlds apart. If you try to imagine any crossover, it is only in the lush gardens of a grand casino or the management of race courses. That said, both can become a dangerous obsession: ambitious aristocrats set out landscape plans they couldn't sustain, and Dutch tulipomania created an economic bubble that led to the crash of 1637. 

But there's another similarity I'm thinking of. Scratch the surface, and horticulture is much closer to gambling than we think, because there's something about the act of gardening that forces us to take chances. It's in its very philosophy, even before we put a seed in the ground.

Firstly, there's a thing called seed viability. Biodiversity International defines this as 'a measure of how many seeds are alive and could develop into plants which will reproduce themselves, given the appropriate conditions'. In other words, if you have a pumpkin seed, does it contain an embryo capable of becoming a pumpkin plant? 

I actually find this definition a little sloppy. It relies on you studying the seed only at a given point, so doesn't take into account the decline in seed viability over time. And without specialist equipment to see whether a seed embryo is alive, amateur gardeners are directly engaged in a game of probability. So for me, seed viability is the changing likelihood over time that a seed, given optimum conditions, will germinate. 

Take the humble Pastinaca sativa, or parsnip, for example. It has seeds with a notoriously short shelf life. If you sow 100 seeds in the first year, you might get 90 parsnips, but 100 of the same seeds the following year might only give you 25 parsnips, so the probability of success drops from 0.9 to 0.25. These aren't cold stats: you're involved in a game of risk and reward. Improve how you store the seed, and you'll raise your chances of digging white parsnipy gold in the Autumn of year two.

There's another side to the game, too. Some friends recently asked me to tell them what was wrong with their ailing mint plant. Its leaves were browning and the soil was dry. It was right next to the window and we had had a couple of scorching days: it didn't show any signs of pests or disease, and was just clearly unhappy with its living arrangements (mint prefers to be a little on the damp and shady side). 

'Will it survive or should we throw it away?' they asked. 

'Well,' I said, 'if you throw it away it definitely won't survive; if you don't throw it away, it might survive'. 

In geeky terms, where A = {The plant survives} and B = {You throw the plant away}, P(A∩B) = 0. You reap what you sow, but you can be sure you won't reap if you don't sow. It's a positive attitude to adopt in life, not just in your herb box: nothing ventured, nothing gained.

But it goes further: every interaction gardeners have is ruled by chance. You look at the weather forecast and don't water your plants because there's 60% chance of rain. You're taking a risk - if it rains, you've saved economic and material resources (money and water); if it stays dry, you've may lose your crop. What's more, in a world where climate change is likely to make weather patterns less predictable, we may find ourselves more often on the wrong side of the die. 

A drought-tolerant garden at Cambridge Botanic Garden

But it makes me wonder: could probability - perhaps even game theory - inform the way we manage our gardens as a way to increase resilience? Adopting a lusory attitude, could we ensure our gardens thrive and survive?

Food for thought.

The semantics of activism

During a bit of channel hopping the other day, I stumbled upon BBC Parliament. I would usually flick straight past in search of the endless reruns of Grand Designs or Location Location Location on More4. But this time BBC Parliament grabbed my eye.

It was the Government's Climate Change Select Committee. They were interviewing two self-defining US climate sceptics, Donna Laframboise and Professor Lindzen from MIT, and climate scientist Nic Lewis, about the IPCC's Report on Climate Change.

Lindzen argued without any substantiation that climatologists were, well, simply a bit thick. Clever kids, he claimed, studied physics or 'math'. It was generally the stupid kids who studied climate.

Nic Lewis said next to nothing.

Laframboise questioned the value of a report written by scientists who had been chosen by governments rather than by the scientific community itself (fair point, perhaps). But she also claimed that we could not trust the accuracy of a report where key sections had been written by activists.

"Marine biologist Ove Hoegh-Guldberg, who has a long history of writing reports for both Greenpeace and the World Wildlife Fund (WWF), leads another chapter. Alistair Woodward, a New Zealand medical doctor, is in charge of a third - despite his nakedly activist worldview." (Written evidence submitted by Donna Laframboise (IPC0039): The Lipstick on the Pig)

This set me thinking. Her use of the word activist is an interesting one. It suggests that the person in question is convinced of something to the point of illogic and anarchy. Perhaps to the point of deviance. And we all know that activism, like disease, spreads.

If Laframboise had been at home in the US, I wonder, could she have evoked the same effect by whispering the word communist?

The sceptic, by comparison? Oh, the sceptic is pure and true, purging the world of deviant activism. Whereas the activist manipulates the evidence for his own quasi-socialist aims, the sceptic reviews the evidence with complete objectivity and condemns the activist before the court.

But does either really exist beyond the word? Is 'sceptic' a sacred inquisitorial robe, donned to bring the bearer authority? And 'activist' the tattered rag which takes it away?

And is the sceptic, with their zeal and ardour, their conviction in face of the evidence, all that different from the activist of their mind's eye?

We got the wong berries, James

Intricate ink

People have sought the exotic, the dangerously unfamiliar, since history began. Spices, such as nutmeg and cinnamon, rare gemstones and precious metals were the prize of medieval merchants, who risked life and limb to make profit from the value these items accrued as they were transported over the threshold into the known world.

No different is the story of plant hunters. From the wondercrop, the potato, to exquisite orchid specimens, over the centuries botanists and bounty hunters have transported cuttings and seeds of plants all around the world. Often documenting them in intricate ink details, they cultivated them, with varying success, in new climes.

 Of course, in many cases, they were not to know the monster they would create. If, in an idle moment, you open the Journal of Horticulture and Practical Gardening (vol. 2, 1881), and turn to page 400, you find a description of a recent arrival from the Himalayas, which was obviously of great excitement to the Victorian gardener:

Himalayan balsam

 “Impatiens amphorata […] – An annual Himalayan balsam, attaining the height of 3 to 6 feet, and described as one of the handsomest species of that section. It was introduced into Kew by seed from Kashmir, and flowers annually abundantly in the months of August and September. It was in cultivation forty years ago in the Horticultural Gardens, having been sent from the gardens of Sabarunpore in North-west India, when these were under the superintendence of Dr. Royle.”

Love your oriental hardies? Then why should the Victorian plantsman stop at Himalayan balsam? William Robinson’s 1871 book on ‘Hardy Flowers: descriptions of upwards of thirteen hundred of the most ornamental species and directions for their arrangement culture etc’ has some novel ideas for bulking out those isolated spaces in your garden:

“If anybody will select some open grassy spot in a pleasure garden or grassy glade near a wood some spot considered unworthy of attention as regards ornamenting it and plant a group of three plants of Polygonum cuspidatum [Japanese knotweed] leaving fifteen feet or so between the stools a distinct aspect of vegetation will be the result. The plant is herbaceous and will spring up every year to a height of from six feet to eight feet if planted well it has a graceful arching habit in the upper branches and is covered with a profusion of small bunches of pale flowers in autumn.”

Japanese knotweed

 Sounds wonderful – and, of course, what’s better than an attractive plant which is prolific, comes back year after year however hard you cut it back, and lacks the natural predators it would have in its native environment?

Nowadays, these carefully cultivated exotic specimens can be found not just in pleasure gardens or grassy glades, but everywhere in the UK (except the remotest moorland in the Highlands of Scotland). Both listed as invasive species by the Environment Agency, Japanese knotweed and Himalayan balsam are officially wanted by the British government.

Cucamelon

With this in mind, I have always been intrigued - yet wary - about James Wong’s Homegrown Revolution. His “delicious, high yielding foods that are expensive to buy in the shops, yet super easy to grow yourself” readily fulfil our desire for new exotics. And like so many forerunners, they promise modern miracles: more food for less money and less effort; something for nothing.

Flick through your catalogue and you find the cucamelon. “These tiny watermelon lookalikes have a refreshing flavour and bags of personality,” the advert reads, before promising taste somewhere between a cucumber and a lime. You know you’re excited; this Mexican delicacy sounds like nothing you’ve ever tried. And in reality, this one is probably attractive enough to slugs to be pretty harmless in the long run.

But I wonder about the goji berry seeds my dad bought me for Christmas. “Highly productive,” the packet boasts; “Easier to grow than a stinging nettle” it adds;” “Delicious & foolproof to grow,” it says. James Wong is casual; he can get away with an ampersand.

Goji berry

So I blithely get on with the business of sowing: “Sow your seeds 13mm deep in a shallow tray of compost and leave on a sunny windowsill at 15-18oC to germinate.” Easily done – what next? “Transplant seedlings into individual 7.5cm pots and keep in a sunny warm spot indoors. Plant outdoors the following year 1m apart, late May/June after risk of frost has passed.”

Thanks James. Oh? That’s not all?

“The goji berry will thrive outdoors and there is absolutely no need to prune or train. The goji berry is a perennial plant and as such will continue to produce fruits each year.”

How kind of it. There’s more?

“You might be surprised to learn that the exotic Himalayan goji berry leads a secret double life as a common, and quite often very invasive, weed throughout much of the UK. Highly productive, delicious and foolproof to grow, before planting one of these it is actually even worth checking that it hasn’t already planted itself in that neglected corner completely unbeknownst to you.”

The alarm bells are ringing. Don’t tell me there’s more..?

“Free from the risk of pests and disease, keep on top of watering and the goji berry is happy to get on with the job.”

The job of being a weed?

I wonder if people in 150 years’ time will come to curse the introduction of the goji berry and the 21st century plant hunter?