Excerpts from Jim Conrad's
Naturalist Newsletter

from the November 27 2016 Newsletter issued from Rancho Regensis north of Valladolid, Yucatán, MÉXICO

In recent Newsletters certain Bean Family vines who folks here had forgotten the names for were identified, mostly on the basis of the flowers. This week another Bean Family vine turned up, but this vine's flowering time had long passed, and all the vine's blossoms had developed into handsome clusters of dangling legume-type fruits like those shown below:


The legumes weren't mature yet, so the flattish beans neatly lined up in the pods were still green, as shown below:

Jícama, PACHYRHIZUS EROSUS, beans in pod

However, at Chichén Itzá back in 2010 a friend showed us mature beans from this vine species, so we know that eventually they turn a rich, dark brown hue, as our picture in the next section.

Despite there being no flowers on this week's vine, the connection between our rancho vine and the Chichén Itzá beans could be made because the vine's large, trifoliately compound leaves are of a very distinct shape, very unlike the leaves of most common garden bean vines, as shown below:


This week's Bean Family vine is the Jícama, PACHYRHIZUS EROSUS, sometimes also known as the Mexican Yam Bean and Mexican Turnip. It really is native to Mexico, as well as Central America. Jícama is a cultivar developed from "Wild Jícama," with the same scientific name. You can compare this week's cultivated form with the wild plant on our Wild Jícama Page, at http://www.backyardnature.net/yucatan/jicama.htm

I won't be sampling the Jícama's beans because they're toxic, containing the compound rotenone, which is used to poison insects and fish. It's the tuberous roots the Jícama gives us to eat. Under ideal conditions the root can grow to 2m long (7ft) and weigh up to 20kg (44lbs). The root has a yellow, papery skin, but inside it's creamy white with a crisp texture like that of raw potato. The flavor is sweet and starchy, usually eaten raw, in Mexico preferably with salt, lemon or lime juice and chili powder. The root also can be cooked and stir-fried in dishes. It's a good source for potassium and vitamin C.

This is another native Mexican plant that has spread to tropical countries all over the world.

from the January 8, 2017 Newsletter issued from Rancho Regensis north of Valladolid, Yucatán, MÉXICO

Jícama is to be planted during the cool season, which is now, so I collected beans from the plant profiled above and planted them. Shelling the beans was complicated by the fact that only about one bean of twenty looked healthy, the vast majority having been eaten by worms or appearing undersize and/or shriveled. Below, you can see what I saw in most pods when I cracked them open -- worms with their poop:

Jícama, PACHYRHIZUS EROSUS, worms eating seeds in pod

Two healthy looking beans along with some undersized and discolored ones are shown below:

Jícama, PACHYRHIZUS EROSUS, seeds in pod

Earlier I'd been given a bag of Jícama beans, but when I planted them not a single plant came up, apparently because the seeds were outdated. This time I wanted to be sure the seeds were viable before they were planted, so I sprouted them using the technique outlined on our bean-sprouting page at http://www.backyardnature.net/simple/alf-spr.htm

Some sprouted Jícama beans just before I planted them are shown below:

Jícama, PACHYRHIZUS EROSUS, sprouting beans

The wet beans were taken to the garden in a water-soaked bandana. Making sure the beans didn't dry, they were inserted into moist, crumbly soil, with the white root tip pointed downward, and covered with a thin layer of soil. Then they were watered, to make even surer that they didn't dry out. That little white root is very sensitive and the least physical impact or dryness might damage or kill it.

from the August 22, 2010 Newsletter issued from Hacienda Chichen Resort beside Chichén Itzá Ruins, central Yucatán, MÉXICO

Luis showed me Jícama beans he'd carried from home in a plastic bag and was about to plant. They're below:

beans of Jícama, or Yam Bean, PACHYRRHIZUS EROSUS

Jícama (HEE-ka-ma) is sometimes referred to in English as Yam Bean. It's PACHYRRHIZUS EROSUS, a member of the Bean Family, native to Mexico and Central America but much planted in the tropics worldwide for its starchy, highly edible tubers.

from the January 22, 2017 Newsletter issued from Rancho Regenesis near Ek Balam about 20kms north of Valladolid, central Yucatán, MÉXICO

Now I can report that close to 100% of the sprouted beans produced healthy seedlings. Below, you can see a seedling just two weeks after its sprouted bean was planted, the seedling already producing a fast-elongating stem clearly yearning to twine around something:

Jícama, or Yam Bean, PACHYRRHIZUS EROSUS, seedling

from the December 3, 2017 Newsletter issued from Rancho Regenesis near Ek Balam about 20kms north of Valladolid, central Yucatán, MÉXICO

Nowadays I'm digging up a fine crop of Jícama tubers. But first, below, take a look at the dried-up Jicama vines in my garden after a full rainy season of vigorous growth:

Jícama, or Yam Bean, PACHYRRHIZUS EROSUS, dried vines on support

Instead of building a trellis for the vines to climb, I took advantage of a 30-ft-long Male Bamboo stem from our bamboo grove, positioning it atop several tripods constructed of poles from the woods. Atop the bamboo stem I hung cut, upside-down, dried-out, leafless bushes and tree limbs with their branch tips touching the ground, for the vines to climb into. The system was easy and fast to construct, and it worked, as you can see from a vine's tubers, which formed close to the soil's surface, shown below:

Jícama, or Yam Bean, PACHYRRHIZUS EROSUS, tuber in ground

Below, that dug-up tuber is seen in my hand

Jícama, or Yam Bean, PACHYRRHIZUS EROSUS, rhizome fresh from soil

My Maya friends tell me that my crop has done OK, though I've seen larger Jícama tubers for sale in local frutarías. Certainly my plants did better than the plants from which last year I gathered the seeds, for they had not been cared for, and the tubers remained small, knotty and woody. Before planting my seedlings, I pickaxed the hard soil, mixed in manure, and watered assiduously.

Here the Maya and I eat Jícama tubers raw. They taste a bit like old potatoes -- starchy with little taste -- though their texture is harder and crisper than a fresh potato. The tubers are washed, peeled and sliced, and eaten without any seasoning, though when they're willing to take the time my Maya friends like to add salt and chili powder, and spritz them with lime juice.