Growing euphorbias without phobia

Succulentophile’s guest columnist, Peter Bangayan, started taking an interest in cacti and succulents about 15 years ago. He joined the Cactus & Succulent Society of the Philippines and became its president from 1998 to 2000. Peter graduated from De La Salle University with a degree in BS Physics and took up his MBA at Ateneo. Aside from growing cacti and succulents, photography, especially black-and-white photography, is one of his passions.

Text & photos by Peter Bangayan

All cacti are succulents but not all succulents are cacti. This is often said at lectures for beginners in growing succulent plants. A lot of people often generalize any desert or xerophytic plants as cacti, but there are many genera of plants growing in the desert that are not cacti. One of these is the genus euphorbia. It is just one of 300 genera belonging to the family of Euphorbiaceae.

Euphorbias generally have very small, insignificant flowers and most exude a milky sap, which in most plants is highly poisonous. The genus includes some 1,000-plus species, including the common poinsettia, which we see so often during the Christmas season, and the common and colorful Euphorbia millii and its hybrids from Thailand.

All succulent euphorbias come from the African continent and the island of Madagascar (whereas cacti come exclusively from the Americas), where they have evolved into forms parallel to that of cacti ranging from globular forms to tall branching ones. The size of mature plants ranges from tree size to a few inches in size. This is called convergent evolution, wherein plants belonging to different, unrelated families develop almost the same physical forms as a result of their adaptation to similar environmental conditions.

Many succulent euphorbias are quite easy to grow in our climate because a large number of them come from tropical Africa in countries like Ethiopia, Kenya, Mozambique, Sudan, Tanzania and Zaire. These countries generally lie near the equator and they have almost the same temperature range of about mid 20s to 30s Celsius except that in our country, we have a much more humid climate.

Succulent euphorbias from South Africa are much harder if not impossible to grow in our climate because they require cool dry nights and have resting periods during South African winter months where they become dormant during the cold and dry season. These include the Medusa-head type of euphorbias such as E. caput-medusae, E. inermis or E. flanaganii. Imported Medusa heads usually survive for a few months or years in our climate but will eventually succumb to rot in our constant humid and hot environment.

Tropical African and Madagascan euphorbias come in many sizes and shapes, from giant tree-size branching euphorbias such as E. antiquorum and E. lactea – which are the common plants we see growing in gardens – to small globular or clumping jewels such as E. francoisii, E. decaryi, or E. gymnocalycioides. Growing and collecting the miniature species can be a fascinating hobby. One does not need a lot of space to grow them, just provide the right environment and they will flourish and provide you with endless fascination and satisfaction. A word of caution though is in order: The milky white sap of most all euphorbias is highly toxic, wash your hands after working with them as touching any sensitive parts of your skin such as the areas in and around your eyes and lips can cause a painful burning sensation in the area. If this should happen, wash the area immediately with warm water and soap. It is said that the sap of another succulent, Aeonium lindleyi, can make the burning stop but unfortunately, this plant is quite hard to grow in our constantly hot and humid climate.

First thing in growing beautiful succulent euphorbia plants is to give them sufficient light. Remember that most of them grow in dry, desert-like environment near the equator so that their light requirement is quite high (although some grow under the shade of other larger plants). A few hours of morning sunlight, as in an east-facing window, is sufficient (but not optimal) for good growth. If given good sunlight, they will grow into compact beautiful plants whereas plants grown in shade can result in straggly, weak, and thin-stemmed growth. Euphorbias are not very particular when it comes to their growing medium, they just need a rich porous medium which can be a mixture of equal parts garden loam, sharp sand and well-rotted compost. When watering succulent plants, the general rule is to water the plants when the medium has almost dried out (not completely dried up). Water thoroughly – one mistake beginners often commit is that they water only the surface of the medium and the water does not reach the roots beneath so that the plants become shallow- rooted.

Any plastic or clay container is suitable for growing euphorbias, just remember that plastic containers are not porous so they will take a longer time to dry out between waterings compared-to-clay containers of similar size.

Some of the easier-to-grow euphorbias include Euphorbia lactea, which occurs in its normal branching form to crested green and variegated forms. As was mentioned earlier, succulent euphorbias come in many different forms. Some miniature creeping stem types of euphorbias include varieties of Euphorbia cylindrifolia, Euphorbia decaryi and the very variable Euphorbia francoisii, which come from Madagascar. Globular types include the common (in the US and Europe but it seems they’re harder to grow here in our climate) Euphorbia obesa, Euphorbia meloformis and the beautiful Euphorbia gymnocalycioides, just to name a few. Some clumping stem types that clump at the base are the miniature Euphorbia dichroa and Euphorbia samburuensis. Euphorbias can also be used as bonsai subjects and some suitable subjects are Euphorbia stellata and Euphorbia persistens, which produces large underground stems which can be raised in cultivation to make them look like old tree trunks. Branching types include the fiercely spined Euphorbia golisana and Euphorbia echinus. One of the rarer and endangered euphorbias is Euphorbia abdelkuri, with stems looking like a melted candle, occurring only on the island of Ab Al-Kuri, which lies in the Arabian Sea off the Horn of Africa.

Growing succulent euphorbias (or cacti and succulents for that matter) can be an interesting and satisfying hobby. The huge diversity of forms never ceases to amaze. Try to grow plants that adapt readily to our climate and you will be rewarded with beautiful showpiece plants.