The Mystery of the Shamrock

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20170317AToday, March 17, is St. Patrick’s Day, celebrated wherever in the world the Irish have settled… that is to say just about everywhere. Like many North Americans, I have Irish ancestors… and I’m far from alone. About 10% of Americans and 15% of Canadians are of Irish origin.

That shamrock is the symbol of the Irish people is very well known and it’s also the official emblem of Ireland, but do you know where this tradition comes from?

Saint Patrick Plucked a Clover Leaf…

Saint Patrick during Boston’s traditional Saint-Patrick Day’s parade. Photo: Laura Siegert, Wikimedia Commons

Saint Patrick is an almost mythical historical figure. Although he probably really did exist, there are so many stories and legends about him that historians have had difficulty determining what really happened. Some even suggest there were two Patricks and that their stories have become intertwined!

Here’s a quick sketch of what might have been Saint Patrick’s life.

Born in Roman Britain around 385 AD, he was reportedly abducted by Irish pirates at the age of 16, then lived as a slave in Ireland for 6 years. It was during this period that he became a devout Christian.

Escaping from his captors, he returned to his family, studied and became a priest. In 432, Pope Celestine, learning he spoke Irish, sent him to Ireland to evangelize the hitherto-pagan Irish people, without much success at first. However, during an impromptu sermon at Cashel Rock, he bent over and plucked a leaf with three leaflets, explaining that it represented the Holy Trinity. That he should so readily find the Holy Trinity in a common weed impressed the pagan Irish and they began to convert to Christianity.

Patrick became the first bishop of Ireland and died on March 17, 461 (maybe!), and the trifoliate plant, which the Irish call shamrock (seamróg), became the very symbol of Ireland.

But Which Plant?

One of the potential shamrocks: lesser trefoil (Trifolium dubium). Photo: Kenraiz, Wikimedia Commons

Therein lies the mystery. What leaf did Saint Patrick pick?

The word shamrock can mean any plant with 3 leaflets. Over the years, experts have suggested that the true Irish shamrock could be lesser trefoil (Trifolium dubium), white clover (T. repens), red clover (T. pratense) or alfalfa (Medicago lupulina), all of which are in the Fabaceae family, or even wood sorrel (Oxalis acetosella), from an entirely different family. All five are common in Ireland and it fact, throughout much of the northern hemisphere.

As for the Irish themselves, a survey conducted in 1988 showed that about 45% consider lesser trefoil (T. dubium) to be the true shamrock while one third prefer white clover (T. trifolium)… and all the others have their share of votes as well. So, no consensus there either.

Your Own Shamrock

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White clover (Trifolium repens). Photo: Ranko, Wikimedia Commons

If you find clover plants with small green leaves on sale around St. Patrick’s Day, a tradition in many countries, the plant sold is inevitably white clover (T. repens), the same clover that grows in so many lawns. It’s easy enough to grow from seed in a florist’s greenhouse, but this cold-climate plant is usually short-lived when grown in a pot and is best planted outdoors if you want to see it thrive.

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False shamrock (Oxalis triangularis)

There is also the false shamrock or purple shamrock (Oxalis triangularis, formerly O. regnellii), True enough, there is nothing truly Irish about this South American plant, but if you want to grow it and claim it as a shamrock, go for it. At least it does makes a good, long-lived houseplant.


It is said that everyone is Irish on St. Patrick’s Day. So wear the green… and show off your shamrock plant, whatever it is!20170317A

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Edible Houseplants

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Coffee fruit - Coffea arabica

A coffee plant (Coffea arabica) will produce it’s colorful “cherries” indoors.

Question: Are there any houseplants that are both edible and attractive?

Clecio Turgeon

Answer: There are many tropical plants that are both easy to grow indoors and give us something to nibble on or to add to our recipes… but you won’t find many among the most common houseplants we grow. Most “everyday houseplants” are either not considered edible or are even poisonous. The latter group includes such popular plants as philodendrons, dieffenbachias, oleanders and most euphorbias. You don’t want to eat those!

What follows is a description of some the more interesting edible houseplants.

 

A Growing microgreens on plastic white cup

Micro-greens aren’t really houseplants.

Plants Dropped From the List

I eliminated from the get-go certain plants that I just don’t consider to be houseplants. For example, I didn’t include most of the herbs brought indoors in the fall to grow over the winter, as in my opinion they are not really houseplants and in fact really struggle to survive indoors. You really couldn’t grow them indoors all year.

Nor did I include herbs and vegetables that are sown indoors with a view towards a quick harvest of fresh foliage: sprouts, micro-greens and baby vegetables, for example. Again, in my book, they may be indoor edibles, but they’re not really houseplants. Likewise rooted carrot tops, sprouted sweet potatoes or celery bases sitting in water. They just aren’t houseplants to me.

There are also a few poisonous plants that are edible only after they’re given some kind of special treatment, like cooking, soaking, pounding or being reduced into powder, such as taro (Calocasia esculenta) and variegated manioc (Manihot esculenta ‘Variegata’). I didn’t think it was a good idea to include potentially dangerous plants in a list of edible houseplants, as some readers might skip the “fine print”.


Everyday Houseplants That Are Edible

Here are the few common houseplants, ones readily found in almost any garden center, that just happen to be edible.

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Calamondin orange (X Citrofortunella microcarpa)

Calamondin Orange (X Citrofortunella microcarpa, syn. X C. mitis)
This is the only citrus commonly offered as a houseplant. It is inevitably already in fruit when you buy it and you just need to give it good conditions (especially, strong light) for it to continue it bloom and produce abundantly. The fruits are very bitter, but they can be used in cooking, especially in the preparation of marmalades. For suggestions of other less widely available indoor citruses, see Indoor Fruits below.

Chinese Hibiscus (Hibiscus rosa-sinensis)
The flowers are edible and often used in herbal tea. Here’s an article about this plant: The Secrets to Growing a Hibiscus Indoors.

Coffee (Coffea arabica)
Young coffee plants, usually scarcely more than seedlings, can easily be found on the market, but may be 2 or 3 years from blooming… and 5 to 6 years before producing enough beans to make a cup of coffee. Occasionally you find more mature plants already producing their highly perfumed white flowers.

You can actually eat the sweet flesh of the coffee “cherries” that follow or simply clean, roast and grind up the “beans” (seeds) to make a delicious drink.

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False shamrock (Oxalis triangularis)

False Shamrock (Oxalis triangularis, syn. O. regnellii)
The leaves of this popular houseplant can be purple or green, with or without a silvery or pink marking… and they are quite edible, with a sweet/sour taste. This comes from the oxalic acid they contain. However, oxalic acid becomes toxic if eaten raw in large quantities, so moderate your use. Or cook the leaves before use. Just to reassure you, remember that spinach, which we routinely eat, also contains oxalic acid and is also toxic if eaten raw in excessive quantities. As they say, the poison is in the dose: eating a few leaves will not harm you.

Ornamental Pepper (Capiscum annuum and others)
All peppers are edible, even the ones sold as ornamental plants. Be forewarned though that ornamental peppers are hot peppers, indeed, very hot peppers, generally stronger then jalapeños.

You may sometimes see them bearing the label “unfit for human consumption”, though. Why is that? It’s not because the fruit itself is poisonous, but because it was treated with an insecticide that is potentially harmful to humans. Organic gardeners will consider the fruits spoiled for life; others can wait a few weeks, then rinse the fruits before eating them. Both can harvest the seeds and grow them to produce fruits totally safe to eat in the second generation.

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Ornamental pineapple (Ananas comosus cv)

Pineapple (Ananas comosus)
There are several varieties of ornamental pineapple, for example with reddish foliage, variegated leaves, colored fruit, etc. And all produce fruits which, although they’re often smaller than commercially grown pineapples, are still edible.

Besides ornamental varieties of pineapple, you can also buy a fresh pineapple and root its crown. And yes, it will eventually produce an edible fruit.

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Lemony rose scented geranium (Pelargonium graveolens ‘Lady Plymouth’)

Scented Geranium (Pelargonium graveolens and others)
There are a multitude of varieties of scented geranium with an incredible array of scents: lemon, rose, coconut, apple. peach, strawberry, cloves, etc. In addition to rubbing the foliage to release their scent, you can use their leaves in cooking to impart a delicious aroma to your meal. Richters (Canada) offers an especially wide choice: more than 70 varieties of these highly perfumed plants!

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Swiss cheese plant (Monstera deliciosa)

Swiss Cheese Plant or Monstera (Monstera deliciosa)
Often mistaken for a philodendron (which is a close relative), the monstera, with its huge, deeply-cut leaves, certainly makes an impressive houseplant. When it reaches maturity, which can take many years, it will flower indoors, producing a white inflorescence recalling a calla lily. And the flower is followed by a sweet-tasting fruit, which is the reason for the botanical epithet deliciosa. The fruit can take 11 to 12 months to mature, and doesn’t change color too visibly at maturity. So how do you know it’s ripe? When the green scales that cover it begin to drop off, it’s ready to eat.

Note that the entire plant, from its roots to its leaves to its immature fruits, is toxic. Only the mature fruit is edible.

Tea Plant (Camellia sinensis)
Yes, tea plants. although not yet as common as the other everyday houseplants presented here, are found more and more often in garden centers. Here is an article about how to grow one: Homegrown Tea in Your Teapot.


Indoor Fruits

There are hundreds of different tropical fruit trees, all of which could theoretically be grown indoors, but most won’t produce for decades, will become too large to make good houseplants or require really extreme growing conditions. Since they are unlikely to ever produce fruit in your home, I excluded them from my list.

In this group of “forbidden fruits”, you’ll find most of the tropical fruits that can be grown from seeds or pits harvested from the fruits you buy, such as avocados (Persea americana), mangos (Mangifera indica), and papayas (Papaya carica). Of course, if you look hard enough, you may be able to find dwarf varieties of these plants that will produce fruits indoors, but otherwise its best to consider most tropical fruits you grow from seed simply as foliage plants!

What follows are a few fruiting plants that are more suitable for growing in our homes and that really do make good edible houseplants.

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Barbados cherry (Malphigia glabra)

Barbados Cherry (Malpighia glabra)
Pretty pink flowers, bright red cherrylike fruits on a small shrub that fits neatly into most home decors. What’s not to like?

Cacao Tree (Theobroma cacao)

A challenge to grow and not readily found on the market, a cacao tree can still produce cacao beans at home… if you turn your home into a hot and humid jungle year round.

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Key lime (Citrusaurantiifolia) makes an easy-to-grow indoor citrus.

Citrus (Citrus spp., Microcitrus australasica and Fortunella spp.)
As mentioned in the article A Lemon or Orange Tree From Seed?, real lemon trees, orange trees, grapefruit trees, etc. are simply too large and too slow to produce to make good indoor fruit trees, unless you can find grafted dwarf varieties.

Other lesser-known citrus fruits, faster in growth and of a naturally smaller size, make much better indoor plants. This is particularly the case for the Meyer lemon (Citrus x meyeri) which, despite its name, is not a real lemon, the Key lime (C. x aurantiifolia) and the Australian finger lime (Microcitrus australasica). You can sow any one of these and have fruit 2 years later!

Kumquats (Fortunella spp.) too make excellent indoor fruit trees.

Common Fig (Ficus carica)
It prefers to pass its summer outdoors… and has the bad habit of losing most of its leaves during the winter, leading to a rather stark appearance, but the fig tree still quite readily produces figs indoors. Moreover, its foliage is edible too.

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Dwarf banana

Dwarf Banana (Musa spp.)
Even a dwarf banana tree takes up a lot of space indoors (among the smallest cultivars are ‘Super Dwarf Cavendish’ and ‘Truly Tiny’) and also require a lot of heat, humidity and sun to produce fruit. Plus they may take years to produce bananas, but still, most will eventually do so if your conditions are right.

The pink banana (Musa velutina), with pink flowers and fruits, is another small-size edible banana you might like to try, but you’ll have to eat around its large seeds.

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Dwarf pomegranate (Punica granatum ‘Nana’)

Dwarf Pomegranate (Punica granatum ‘Nana’)
This is a miniature version of the rather large pomegranate tree whose fruits are found in the supermarket. It forms a small to medium-sized shrub with orange flowers that will readily produce small but nevertheless edible fruits indoors. Even if you grow it from seed (it comes true to type), it will bear blooms and fruits in only a few years.

Natal Plum (Carissa macrocarpa)

This small thorny shrub with shiny leaves makes a good houseplant and readily produces white flowers and edible red fruits. It is sometimes used as bonsai. Both the stem and leaves, and even the sap, are poisonous. Only the ripe fruit is edible.

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Passionfruit (Passiflora edulis)

Passionfruit (Passiflora edulis)
This vigorous climber will need a good trellis, but can produce its white flowers with a purple halo and its purple or yellow fruits (the color depends on the cultivar chosen) in a sunny spot indoors. There are plenty of other species of passionfruit that do well indoors, but only a few produce edible fruit.

Pitahaya or Dragon Fruit (Hylocereus undatus, H. polyrhizus, H. megalanthus and others)
These climbing cacti take up a lot of space, but bloom fairly easily when they reach maturity (after 5 or 6 years), producing enormous white fragrant nocturnal flowers followed by large red or yellow fruits with white flesh that is dotted with tiny black seeds. This is a good example of a plant you can grow to fruiting size from seeds harvested from fruit purchased in the supermarket. You just have to be patient!

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Fishbone cactus (Epiphyllum anguliger)

I grow a smaller and closely related cactus, the fishbone cactus (Epiphyllum anguliger), with hanging flattened zigzag stems whose very fragrant nocturnal white flowers often give small edible green fruits… but it’s difficult to judge when they are ripe. It too takes years to begin to bloom, but once it starts, it will faithfully continue to do so.

Pixie Grape (Vitis x Pixie® Pinot Meunier)

A dwarf mutation of the Pinot Meunier grape vine which produces fruit all year on a small plant… and its leaves are edible too. It can be grown as a houseplant, but is also hardy outdoors.

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Roselle (Hibiscus sabdariffa)

Roselle (Hibiscus sabadariffa)
This shrub with small yellow hibiscus flowers grows quickly from seed. In fact, you can treat is an annual if you wish. It produces red fruits often used in drinks and jellies.


Indoor Herbs and Spices

Herbs and spices flavor our meals and often have medicinal uses as well. I limited the choice here to varieties that really make decent houseplants.

Bayleaf (Laurus nobilis)
In my opinion, this is the only “classic” herb that grows well enough indoors to make a good houseplant. It will grow indoors for years, eventually forming a tall shrub if you don’t prune it. The leaves can simply be plucked and used fresh as needed.

Black Pepper (Piper nigrum)
This climbing plant produces smooth shiny leaves and long spikes of green berries that turn red at maturity and is not difficult to grow indoors if you can offer good humidity. The berries give black, white or red pepper, depending on the treatment you give them.

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Ginger (Zingiber officinale)

Ginger (Zingiber officinale)
You can readily grow ginger from rhizomes purchased locally. Beware though that the rhizomes offered in many supermarkets were treated chemically or irradiated in order prevent them from sprouting. There is no use planting those! You need live rhizomes, with buds indicating they are ready to sprout. An Asian supermarket should have some.

Just push a section of rhizome into a pot of growing mix and water: a green rather bamboolike plant will soon start to sprout. Over time, the rhizome will spread and you can then harvest and eat any surplus. Don’t expect this plant to flower indoors, though: it almost never does.

Other spices in the ginger family also produce edible rhizomes and likewise make excellent houseplants: galanga (Alpinia galanga), turmeric (Cucurma longa) and cardamom (Elettaria cardamomum) are only a few examples.

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Society garlic (Tulbaghia violacea)

Society Garlic (Tulbaghia violacea)
This is a bulbous plant with grasslike leaves and small pink trumpet flowers. The whole plant smells like garlic. If you use the edible leaves and flowers in your cooking, they’ll give the meal a garlicky scent, but without the bad breath that follows eating real garlic. The name society garlic come from the idea that you could safely eat it before attending polite society functions.

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The variegated forme of Spanish thyme (Plectranthus amboinicus ‘Variegatus’) is probably more popular than the species.

Spanish Thyme or Cuban oregano (Plectranthus amboinicus)
This plant is neither a thyme (Thymus spp.) nor an oregano (Origanum spp.), but rather a tropical plant closely related to the coleus (Plectranthus scutellaroides, syn Solenostemon scutellarioides and Coleus blumei). It’s a very popular herb in tropical countries where its thick leaves lend taste of oregano to cooked dishes. It’s very easy to grow.

Stevia or Sweetleaf (Stevia rebaudiana)
Increasingly popular for its sweet leaves that give dishes a sugary flavor without adding calories… and it makes a decent houseplant.


Indoor Vegetables

There aren’t many plants you could call vegetables that also make good houseplants. I could only think of the following two:

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Malabar spinach (Basel alba ‘Rubra’)

Malabar Spinach (Basella alba)
An ornamental climber with mucilaginous leaves used to replace spinach, Malabar spinach is often grown in hot climates where real spinach doesn’t grow well. The species itself produces green stems and white flowers, but B. alba ‘Rubra’, perhaps even more commonly grown, has reddish stems and pink flowers. Both are very easy to grow.

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Spineless nopal (Opuntia ficus-indica ‘Burbank Spineless’)

Nopal or Barbary Fig (Opuntia ficus-indica and others)
Many different opuntias are used as nopals, but Barbary fig is the most common one. This cactus with flattened pads does produce edible fruits called Barbary figs when grown outdoors in a hot, dry climate, but indoors it rarely blooms, let alone produces fruit. It made it onto my “edible houseplant list” by virtue of its edible pads.

Nopal is the name commonly used in Mexico for the pads treated as a vegetable. You’ll probably need several plants if you want to start harvest nopals, as the plant is very slow growing. You have to singe off the spines before you eat the pads… or use spineless (or nearly spineless) cultivars like ‘Burbank Spineless’.

This plant will need full sun to do well indoors. And yes, you can root a pad from the grocery store to start a new plant.

Where to Find Edible Houseplants?

Many of the plants above are not found in just any garden center, so here are few places where you might want to look for them on the Web.

For herbs and species, try Richters, a Canadian company that ships to the US and probably offers more choices of herbs than any other.

For unusual fruits and vegetables, try Flora Exotica, also a Canadian company that ships to the US, while Top Tropicals is an American company that ships to Canada and many other countries worldwide. Logee’s, in the US, is a good source for American readers, but no longer ships to Canada.

For European readers, try AlsaPlants. If you know of any other good mail-order sources of indoor edibles in Europe, let me know and I’ll add them to this text.

Bon appétit!

Grow Your Own Shamrock Indoors

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20160317BIt is said that on St. Patrick’s Day, March 17, everybody is Irish. Okay, but are you an Irish gardener? If so, why not grow an Irish shamrock in your home?

A Plant of Legend

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White clover (Trifolium repens) is one of several plants sometimes touted as the “true Irish shamrock”.

The shamrock is a legendary plant with three leaflets. Saint Patrick is said to have used it to teach the Holy Trinity to the pagan Irish back in the 7th century, converting them to Christianity. The problem is that nobody really knows which leaf he used: was it a clover, an alfalfa or an oxalis? The Irish name shamrock is of no help. It means, quite literally, “small three-leaved plant”, which could mean just about anything. I figure this gives the indoor gardener a certain freedom of choice, but since neither clover (Trifolium) nor alfalfa (Medicago) make good houseplants – and since both are solidly frozen outdoors in most regions on Saint Patrick’s Day – I suggest using the oxalis as a living symbol of your Irish heritage.

An Indoor Shamrock

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The original false shamrock (Oxalis triangularis) had green leaves and white flowers, but more colorful varieties have taken over the houseplant market.

The false shamrock, also called purple shamrock or love plant (Oxalis triangularis, formerly O. regnellii) is probably the best species to use as a houseplant. It is adapted to subtropical conditions and thus easier to grow in the average heated home than more temperate oxalis species. Of course, since it hails from South America, it is certainly not the true Irish shamrock… but if you don’t tell anyone, I won’t either.

The distinguishing feature of this plant is that each of the three leaflets that make up its leaf is almost triangular. They are carried on long petioles, upright at first, but eventually arching or even drooping under typical indoor conditions, forming a dome as wide as it is tall. The leaflets have the curious habit of closing at night, folding one against the other.

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Most modern cultivars have purple leaves and pink flowers.

The leaves of the false shamrock were originally plain green, but there are now many cultivars with purple foliage or with a silver or metallic pink mark on the leaflets. Similarly, the five-petaled flowers, which were white in the original species, are pink in the case of many cultivars.

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Rhizome (photo: Wikimedia Commons)

False shamrock grows throughout the year indoors and is almost never without flowers. Out of sight under the soil are scaly rhizomes in which it stores energy for future use. So if you ever stop watering your oxalis, it won’t die but will simply go dormant and lose its leaves. It will then grow back from its underground rhizomes when you start to water it again. That’s because plant evolved to cope with occasional droughts in its natural environment.

This makes it the perfect plant for Snowbirds, as they can leave their oxalis totally on its own for six months without having to worry about having someone come in to water it, then it will grow back quickly when they get home and start to water it again. The rhizomes are also used for multiplication. Just dig up one or two, pot them up and you’ll quickly have a pot of true false Irish shamrock to share with friends and neighbors.

How to Grow False Shamrock

This is a very easy houseplant to care for.

Average home temperatures suit it perfectly (at less than 50°F/10°C or more than 90°F/32°C, however, it may go dormant) and it adapts to most light situations, from dim to bright. However, it prefers bright light during the winter. It also tolerates dry air, although it does better in a humid atmosphere. The only truly essential maintenance is watering: to keep growing, water it regularly, whenever the soil feels dry to the touch. You can add a diluted dose of the fertilizer of your choice between March and October… but even if you do never fertilize your oxalis, it will still grow very well.

In addition, false shamrock rarely suffers from insects or diseases. If you ever detect a problem, you can quickly solve it: chop the leaves to the ground to eliminate the pest and the plant will grow back quickly. After two weeks, your plant will be healthy again, new leaves will be growing and it will soon be in bloom!

So much for the good news. On the negative side, false shamrock is a messy plant, requiring frequent cleaning. The leaves and flowers are short-lived and if you don’t remove the faded ones every three or four days, they build up and diminish the plant’s attractiveness.

Surprising Facts

Curiously, false shamrock is grown as a vegetable in many South American countries. People consume the leaves and flowers, but especially the rhizomes, serving them either as a side dish or a condiment. All have a delightfully tangy taste, like sorrel or rhubarb. Don’t overdo it though, as all its parts contain oxalic acid which is toxic if consumed in large quantities. In South America, it is generally held that you should not eat oxalis more than three or four times a week.

If you have pets (dogs, cats, etc.) be forewarned that they don’t know that they should be consuming this plant in moderation and could become sick if they eat too much. Most pets don’t like the taste of false shamrock and will stop chewing after the first nibble. However, if your little friend is given to munching plant parts, you’d do best to keep your oxalis out of its reach.

You can also use this oxalis outdoors during the summer, in pots or planted in the garden, in sun or shade. The easiest thing to do is to cut the leaves to the ground before you plant it out. That way you won’t have to worry about slowly acclimating the plant to outdoor conditions like you would with most plants you’re transitioning to outdoor growing; the new leaves that grow in will automatically adapt to outdoor sun.

This oxalis is hardy from USDA zone 7 to 10. It therefore won’t be hardy in northern climates and will have to be brought back indoors in the fall. It warmer climes it can remain outdoors all year. Unlike many oxalis species, false shamrock is not invasive and will remain in its place unless you disturb the rhizomes. Rototilling, notably, could spread them far and wide.

20160317HBeannachtai na Feile Padraig! (“Happy St. Patrick’s Day!” in Gaelic.)