Guillermo Lopéz Meléndez is a popular guy in the leafy suburb of La Condesa, a place that overflows with jacaranda flowers in March and April and walls of four-dimensional bougainvillea all year round. He has a high-profile corner of Condesa, where Michoacan crosses Avenida Mexico, and on weekends he sells money plants, along with tubs of mint, sage and basil, and sword ferns in clumps bigger than a ride-on lawnmower.

His money plants are easy to identify. They’re sharp-edged little succulents, dressed up with ribbons in red, yellow, purple and white. Guillermo’s a practical man, and plucky: he takes over the street every Saturday and Sunday with his well-curated army of plants, and to hell with passing cars. When talking about the power of money plants though, he’s hushed.

“These are sabila,” he says, pointing reverentially to a cluster of aloe plants. The ribbons, he explains, are for love (red), money (yellow), safety (purple) and health (white). It’s essential to give them as a gift, or the luck won’t be properly transferred according to collective wisdom. “You’ve got to talk to the jardineros in the south about it, they know the secrets,” Guillermo recommends.

By the south, he means Xochimilco. It’s the centre for all growing things in Mexico City, where floating farms pop up out of the World Heritage canal system and streets are double lined with plant sellers. Mercado Madreselva is the beating pulse of all this botanical wealth.

Even if you take only an idle interest in plants, you need to exercise a great deal of restraint in the market. Stallholders sit back silently and let the plants do the work. They lure you in with signs offering rosemary, marigolds and coriander plants for five pesos, or roughly 40 cents. Huge white pots decorated like mirror balls will comfortably fit a tree or an oversized agave tequilana and go for 150 pesos. Twelve dollars, say.

Dotted amongst the aisles are jade plants, Swedish ivy, aloe and piggyback plants, all glowing with health. It’s a line-up of leafy characters that could make you very rich. According to the wisdom of Xochimilco, these plants deliver wealth to their bearer and with this promise the plants have become demigod-like figures for adherents of the cult of lucky plants. Believer or not, it’s hard to resist the call of a plant that could help land a few extra dollars in your back pocket.

The most exalted of the money plants in Xochimilco is the planta millonaria. Tolmiea menziesii is native to the west coast of the US, from California up to Alaska.  It’s known by a bundle of nicknames there: the piggyback plant, thousand mothers and youth on age. In Mexico it’s simply planta millonaria, the millionaire plant. It has generously sized, hairy ear-shaped leaves and occasionally flowers.  Hanging in your kitchen or balcony it serves as a lightning rod for money, and is quietly good-looking too.

The millonaria’s fame and fortune could be related to its ability to self-sufficiently sprout up from itself. Mini versions of the plant are able to grow near the base of each leaf and then establish themselves as distinct, breakaways by dropping off and taking up root in the soil nearby. It’s an eagerness for propagation that’s akin to the mechanics of a mint: an in-built license to replicate. At Mercado Madreselva you’ll find hanging pots of planta millonaria that’ll only set you back 10 to 20 pesos, a reasonably priced investment for any budding tycoon.

To double your luck, plant sellers recommend burying a handful of coins and dried chiles in the soil surrounding the plant. While the trick is unlikely to turn your millonaria into a billonaria overnight, it could result in a habanero or jalapeño seedling popping up in your near future.

Planta del dinero is a gangly green plant best suited to hanging pots and sunny perches. Its botanical name is Plectranthus australis and commonly, Swedish ivy. It’s a no-nonsense money plant native to Australia and South Africa. Its leaves resemble immoderate, glossy coins tumbling down in long cascades from its root base. In Mexico City you see them in shop fronts and windowsills, bringing home the bacon.

Ask any of the plant vendors in Xochimilco which plants will make you rich, and they’ll share with you the inside know-how for generating fiscal good luck with the aid of a plant. The male aloe vera, for instance, will attract money and ward off mala vibras (bad vibes). Save the female of the species for bad sunburn, pimples and for use as a natural hair conditioner.

Jade is the arbolito de la abundancia, the little tree of abundance.They’re available bonsai-ed, potted, surrounded with fluoro pebbles and matured, up to a metre tall. “Ten pesos is not a lot to pay for a lifetime of abundance,” says a serious teenager manning one of the stalls at Mercado Madreselva. It’s very hard to disagree.

The cult of lucky plants is an easy cult to belong to. It demands little more than the cost of a taco to join. Its idols are health and prosperity. Ongoing sacrifices consist of care, water and affection for your plant. In return, the plant will fill your home with life, and perhaps reveal to you in some way or another the winning numbers for Saturday night’s lottery. It’s a bet worth making.