Moving the Madman’s Euphorbias

Nights are truly warm now so moving day has arrived. The madman is moving his precious Euphorbias and other succulents to the Cactus Garden. As he walked by with a large prickly plant, I made the comment, “Wow! That’s a nice Cactus.” Wrong thing to say – he got very indignant and said, “This is not a Cactus – this is a Euphorbia.” I knew that, it’s just much easier to say Cactus instead of Euphorbia, besides they look so much alike.

Random Collecting

The madman has been collecting Euphorbias for a good many years. In the early years he was only collecting plants that caught his fancy. He never paid attention to names – the plants were cool and that’s what mattered. So his collection grew; plant by plant. There was the Pencil Cactus, the Softball Cactus, the Milk Plant, the Crown of Thorns – all lumped together as cactus: nothing more, nothing less.

In fact, some of the plants he got didn’t even have a name – they just had a tag that said “Assorted Cactus and Succulents.” Now, if the tag doesn’t list the Latin name, he doesn’t buy it (unless it is just too cool to pass up, that is – then he spends days trying to figure out what it is). So, what changed? His Eureka moment happened half way through our Master Gardening program when we went through the Horticulture Exhibit at the Connecticut Flower & Garden Show.

Proper Names

We were learning about scientific names and the importance of correct nomenclature. But, it really hadn’t sunk in. Suddenly, the madman came to a dead stop in front of me. “Hey,” he said. “My pencil cactus is not a cactus at all – the tag says Euphorbia trigona.” And, a plant like his softball cactus was labeled Euphorbia obesa.

So, his favorite plants weren’t cactus at all – they all belonged to the family Euphorbiaceae instead of Cactaceae. To the casual collector, it doesn’t really matter, but remember I’m dealing with a madman with a scientific background. It does matter.

Names Matter

But why? First of all, if you want to grow a healthy, happy specimen, you should replicate its ancestral growing conditions. For example, a plant from the deserts of South Africa like Euphorbia cooperii is not going to be very happy planted in a rich organic medium and watered daily. But, it will thrive in a course sandy mix that receives infrequent watering and lots of sun. I’m beginning to see why he likes these plants…less watering sounds like less work to me.

Also, the madman likes to show his plants at the Standard Flower Show during the Connecticut Flower & Garden Show in Hartford. Can you imagine what would happen if he showed up with a “Pencil cactus” entry form attached to his Euphorbia trigona? He and his plant would be booted out the door with no ceremony. All entries must be correctly identified by Genus and species. No exception, even for the madman. And, he does usually enter several Euphorbias in this show.

Honoring Euphorbus

Pliny the Elder named these plants Euphorbias to honor Euphorbus, the physician of King Juna II. Apparently Euphorbus had successfully treated the king using these plants. In 1753, Carl Linnaeus made the name official by describing Euphorbia in his Species Plantarum. The genus contains over 2,100 species, making it the fourth largest flowering plant genus in the world. But, a lot of its members get confused with cacti.

Convergent Evolution

Thank convergent evolution for the confusion. This is an evolutionary process where plants of different lineages develop similar traits. An example often used is the Euphorbia and the Cactus. Both developed in harsh arid conditions, but continents apart. Both plants had to survive life in the desert where rain was scarce. Their methods of survival were similar, but different. Like the Cactus, Euphorbias developed efficient ways to store water. They are both succulents and can go for long periods without additional water.

In the Americas, Cacti developed spines which protect them from the sun and from hungry predators. At the same time, the Euphorbias in South Africa developed a different mechanism for protection. Here, a milky sap running throughout the plant is toxic if touched or ingested. Some Euphorbias do have thorns, often confused with spines, but the plant’s main means of protection is the milky sap, often referred to as “latex”. I suspect that it’s the milky sap that fascinated the madman – he has this thing for poisonous plants.

Cactus Garden Annex

So, back to moving day. The madman’s Euphorbias love summers – especially hot dry summers. And, moving day is special this year because the Cactus Garden has a new annex – the front of the house. In the past, we have tried growing lots of different things in front. The morning glories did the best and we loved them. But, as they aged, they got messy from the bottom up. It was time for a change. And, with the madman’s adventures in succulent propagation, we needed more desert-like areas. The front of the house was perfect.

The madman removed all the rich garden soil and replaced it with sand from the original cactus bed. He does love projects. Because he likes to enter his plants in various flower shows, not all the Euphorbias will make the trip to the outside beds. He has learned the hard way that because Euphorbias are not natives, animals don’t know of their toxicity until they take the first bite. But, by then, the damage is done and the plant is no longer show-worthy.  This might be a reason why he is propagating so many.

Favorites

Although the madman has many different species of Euphorbias, he does have some favorites. At the top of his list is the Euphorbia tirucalli, commonly, but erroneously referred to as a “Pencil Cactus.” Our first specimen came from a well-regarded nursery that probably should have given it the correct name. E. tirucalii is a succulent shrub that hails from the deserts of Africa. In the wild it can grow upwards of 20’. The madman’s plants don’t get nearly that big which make them a great houseplant. Its inconspicuous flowers grow at the end of pencil-like stems which often have leaves that drop off. Neither leaves nor flowers are noteworthy on this plant, but the stems make it fun to grow.

African Natives

Running a close second is E. grandicornis, a species from southern Africa which is often confused with Cacti. It’s an upright succulent shrub with pairs of thorns that resemble small cow horns. In the wild, it can grow up to 6’ tall, but the madman carefully prunes his plants to keep them in check. Unfortunately, the prunings are easily rooted.

The E. trigona, known as the African Milk Tree, is the madman’s largest specimen. The species comes from West Africa where it can reach heights of 7-9’, forming dense thorny thickets. The madman’s first specimen came from a local nursery that was closing. He still remembers me coming down the driveway with a large plant sticking out of the passenger side window. I didn’t know what it was, but the price was right. The madman was thrilled. Since that time, he has acquired several more E. trigonas, including a red cultivar and a variegated specimen.

On To Madagascar

So far, these plants have all come from continental Africa, but there are Euphorbias that have developed separately on Madagascar, a large island in the Indian Ocean that has been isolated from neighboring continents for a very long time. Because of its isolation, Madagascar is the home of some unique species of animals and plants.

One of the plants is Euphorbia milii, also known as the Crown of Thorns. This evergreen shrub sports fancy blooms which are in reality colorful bracts that surround the inconspicuous flowers. They are easily propagated and have been bred to produce bracts in a variety of colors.

Another Euphorbia from Madagascar is E. geroldii, often referred to as a “thornless” Crown of Thorns. Like its cousin E. milii, it’s a succulent shrub that grows up to 2’ tall, but there its similarities end. It has no thorns which makes it easier to handle, and its leaves are a glossy darker green.

Euphorbias Don’t Like Cold

Of all the madman’s succulents, the Euphorbias seem to be the most cold-intolerant plants of the bunch. According to some of his friends in the Connecticut Cactus and Succulent Society (CCSS), Euphorbias will tolerate nothing less than 50˚, so he overwinters them in the house, not the greenhouse. As a quick side note, if you like succulents or cacti and you live in Connecticut, you should really join the Connecticut Cactus and Succulent Society – the dues are reasonable, the meetings are fun and the members are not only friendly but extremely knowledgeable and willing to share their knowledge.

One of these days, we’ll start to feel more comfortable about going out and we’ll be able to go back to meeting in person with the CCSS. Until then, the madman has to be content with playing in his own cactus bed (I call it his sandbox). His Opuntia humifusa has started to bloom and he is busy arranging the less cold tolerant species around the yellow flowers. Time for a break.

Lemonade is ready.