Monday, December 26, 2011

Toad cactus, anyone?

Toad cactus, starfish cactus, star flower, leopard print flower.

It always amazes me how many common names a plant can have, especially one that is anything but common in our part of the world. Let’s not forget the catchall moniker “carrion flower,” which seems to be used for scores of plants, many of them not even related.

Toad cactus (Orbea variegata)

The plant I’m talking about—and which I will call “toad cactus” even though it’s not a cactus—is found in the Western Cape province of South Africa. (Lately it seems that virtually all the intriguing plants I come across are from South Africa.) Its Latin name is Orbea variegata; in the past, it was included in the genus Stapelia, and looking at the leaves and flowers, it’s easy to see why. For comparison, check out the photos of Stapelia gigantea I included in this recent post.

Like all stapelias, the toad cactus has long leafless stems that look like green rope. In the ground, it forms attractive mats. In cultivation, it looks best in a hanging pot where the stems can dangle freely.

As nice as Orbea variegata looks year round, its flowers are particularly stunning. The stapeliads are often called the “orchids of the succulent world,” with good reason. Their flowers are complex and intricately patterned and, to my eyes, very attractive. Their somewhat unpleasant scent—designed to attract flies which act as pollinators—is not as off-putting as some people claim, and it doesn’t seem to last very long.

Orbea variegata needs full sun to grow well and especially to flower. Supposedly, it can take high temperatures. Its stems will turn reddish brown in hot conditions but that is a perfectly normal adaptation (as with aloes).

There is conflicting information regarding its cold-hardiness. Some sources say zone 10, others zone 9. Brief exposure to temperatures in the 28-30°F range are probably OK, but I doubt it would be able to survive at temperatures much lower than that. I’m happy to experiment next winter if my cuttings root and I end up with more than one plant.

Which brings me to how I found out about Orbea variegata. My in-laws’ neighbors have a large plant (see the two photos at the top of this post) in their living room. Since my mother-in-law knows how fascinated I am by succulents, she got several cuttings for me. I had never heard of Orbea variegata before, but apparently it is the most common stapeliad in cultivation. Common or not, its flowers are anything but.

Orbea variegata flowers
Orbea variegata flowers
Closeup of Orbea variegata flower
Orbea variegata flower closing up after it’s done blooming
Orbea variegata flower closed up completely after blooming

There appears to be quite a bit of variation in the flowers. This form, for example, is creamier overall, with fewer spots and pointier lobes.

In Europe, Orbea variegata has been in cultivation since the 1700s as Stapelia gigantea. This illustration was published in Volume1 of The Botanical Magazine (1790).

Illustration of Orbea variegata (Stapelia gigantea) in Volume 1 of The Botanical Magazine, published in 1790
Photo source: Wikimedia Commons

I love discovering new plants, and I’m happy that 2011 is ending on such a high.

One of my Orbea variegata cuttings, stuck in dry soil mix in a makeshift container
(it was too cold to root around in my in-laws’ shed for a proper flower pot)

Sunday, December 25, 2011

Happy holidays


Happy holidays to everybody, no matter what holiday you are celebrating. I hope you’re having a wonderful time with family and friends!

Saturday, December 24, 2011

Frost protection can be beautiful

The Thursday night weather forecast called for a low of 25°F—the lowest temperature of the season thus far. While all of our outdoor succulents are hardy to 28°F, some start to get damaged at 25°. Three degrees make a big difference for some plants, including our large Agave desmettiana ‘Variegeta’ which got damaged two winters ago at 26°F when I accidentally left it unprotected.

On Thursday afternoon, we draped incandescent holiday lights over our succulent bed, including a net like this one, and then added frost blankets. To make sure the blankets stayed in place, we weighted them down with rocks and other objects (like the saucer in the photo below).

When the lights came on in the evening, I was surprised by how festive the lights looked, creating interesting shadows under the blankets.


I had run out of frost blankets to cover my prized cow-horn agave (Agave bovicornuta) so I moved it up against the house and draped lights over it. Doesn’t it look like the succulent version of a Christmas tree?


A temperature check on Friday morning revealed that the nighttime low had “only” been 28°F—whew! I’m leaving the frost blankets and lights up until after the holidays in case Santa decides to send another cold front our way. That way I’ll be prepared and won’t have to scramble. After all, Christmas is supposed to be peaceful and relaxed!

Friday, December 23, 2011

House guests for the winter

This year saw the addition of a number of tender plants to my succulent collection. For the first time ever, I’m forced to overwinter plants inside the house since I don’t have a greenhouse or conservatory. Most these are “fat plants,” a category made up of caudiciform and pachycaul plants. “Caudiciforms” have a swollen base or enlarged underground stem (known as a “caudex”). “Pachycauls” have a thickened or swollen trunk.

All fat plants hail from warm climates, necessitating winter protection. Some of them might be hardy enough to spend the winter outside, but I’m not taking any chances since they’re still small. Others need temperatures consistently above 55°F. This is new territory for me and I still have a lot to learn. However, my fascination with these odd plants is so strong that I’m willing to go the extra mile to give them what they need to survive and hopefully thrive.

Here are the plants that are spending the winter near the large window in the loft. This window faces west so it doesn’t receive as much sun in the winter as it does in the summer. However, there are also three south-facing windows to the left that provide extra sunlight.

House guests huddling near the large upstairs window

Since most of these plants are quite small, they don’t look like much. At first glance you might wonder why I would want to collect something so plain or uninteresting. For this reason, I’ve added photos of larger specimens, either in the wild or in cultivation. At least you’ll get a better idea of the potential these plants have, even though few of them will ever get to the size they would reach in their native habitat.

LEFT: Sinningia tubiflora (click here to see a blooming specimen)
MIDDLE: Pachypodium namaquanum
RIGHT: Adenium obesum

Pachypodium namaquanum

In its native habitat in South Africa and Namibia, Pachypodium namaquanum can grow to 12-15 ft. in height. The tapering trunk is studded with spines that give it a textured look. According to Wikipedia:

Seen from a distance, the plant has the appearance of a person trudging up a slope whence its common name of "Halfmens" (Afrikaans for 'semi-human').

My small Pachypodium namaquanum
Pachypodium namaquanum in its native habitat
© Graham, Reproduced with permission.
Click here to visit Graham’s fascinating blog from Namibia.

Pachypodium succulentum

My second pachypodium, Pachypodum succulentum, is also native to South Africa. It is supposed to be able to withstand light frost, so I may leave it outside next year. Collectors grow it not only for its caudex but also for its attractive flowers that can range from pink to crimson (see the 2nd photo below).

My Pachypodum succulentum
Photo source: Wikimedia Commons

Adenium obesum

The best-known caudiciform is the desert rose (Adenium obesum). While not completely mainstream, it’s not a rarity either. I sometimes see it for sale at the garden centers of the big home-improvement chains, or even at Walmart. In recent years Adenium obesum has been heavily hybridized to create new flower colors and shapes, such as double flowers. It is particularly popular in India, Thailand, and Taiwan. Check out this interesting article on the adenium industry in Asia; this site also has useful cultivation information.

I have two desert roses. One is small (in a 4-inch container) but with a relatively fat caudex.

My Adenium obesum, small but fat

The other is much larger overall, with larger leaves but a smaller caudex. But plants are dropping leaves right now, entering a phase of semi dormancy. The biggest threat at this stage is overwatering which might lead to rot, so I’m being careful.

My other Adenium obesum, taller but with a smaller caudex

Adenium obesum is indigenous to eastern and southern Africa and parts of Arabia. In its native habitat (see photo below) it can reach heights up to 12 ft. but in cultivation it’s much smaller. 

Photo source:

The desert rose has attractive flowers that can be shades of pink, red, white, or a combination thereof. Supposedly they can flower anytime of the year, although spring and fall are more typical. They prefer sunny—even hot—spots and can take a lot of water when actively growing. In the winter, they need to be kept on the dry side, especially when they drop their leaves. This holds true for all fats plants described in this post.

Photo source:  Wikimedia Commons

Fockea edulis

Fockea is a genus of caudiciform plants native to South Africa and Namibia. In situ, the caudex can be up to 2 ft. in diameter and is usually completely buried. In cultivation, the caudex is raised for display purposes. When actively growing, fockeas produce vines that can grow to many feet (one source says up to 12 ft.). For older plants, a support needs to be provided. My Fockea edulis is small so I just let the vines scramble up the window.

111218_Euphorbia-francoisii Fockea-edulis
Fockea edulis (on the right)
This is what a larger specimen looks like. The caudex is very impressive.
Photo source: Cactuspedia, one of my go-to sources for high-quality information and photos about succulents

Dendrosicyos socotrana

Dendrosicyos socotrana is a bottle tree only found on the island of Socotra off the coast of Yemen. It’s common name is “cucumber tree,” alluding to the fact that botanically it’s a member of the Cucurbitaceae (or cucumber) family. In its native habitat, this pachycaul can grow to 18 ft.

I got my specimen from the UC Davis Arboretum which has had a great track record of growing this very rare plant from seed. This is what it looked like originally:

My own Dendrosicyos socotrana on 9/25/11…

I left my newly purchased plant outside in a full-sun position and its leaves promptly began to dry up, probably because it had been kept in a greenhouse at UC Davis and wasn’t used to full sun. Fortunately, after a short while, new leaves began to appear. This is what my Dendrosicyos socotrana looks like now, happily ensconced inside the house:

…and on 12/18/11
New leaves, 12/18/11

In its native Socotra (the only place in the world it is found), Dendrosicyos socotrana grows into a strange-looking but oddly majestic tree:

Photo source:
Photo source:

Stapelia gigantea

Stapelia gigantea, commonly called “carrion plant” or “toad plant,” is found in southern and eastern Africa and superficially resembles a euphorbia or cactus. They form ever-increasing colonies and in the summer produce very large flowers which release an odor of rotting meat in order to attract pollinators, mostly flies. Stapeliads are very popular with collectors and a great deal of information is available on the web. This is a good place to start if you want to find out more.

111218_Stapelia-gigantea Euphorbia-cylindrifolia
My own Stapelia gigantea (left), purchased in November at Poot’s Cactus Nursery
Stapelia gigantea flower. I chose this photo because the hand gives a sense of scale.
Photo source: Wikimedia Commons

   Euphorbia cylindrifolia

The next five plants are all members of the genus Euphorbia. It’s one of the largest and most diverse genus in the plant kingdom, comprising more than 2,000 species that range from shrubs and trees (many resembling large columnar cacti) to annuals and perennials. The poinsettia is a euphorbia, as are crown of thorns and the European spurges.

The genus Euphorbia also comprises a number of oddities, like Madagascar native Euphorbia cylindrifolia. Its stems resemble octopus tentacles and even its leaves look strange. Eventually, it forms a large underground caudex which can be raised (see 2nd photo below, taken by my friend Candy “Sweetstuff” at the Huntington Botanical Gardens in Southern California).

My Euphorbia cylindrifolia in a 4-inch container
Euphorbia cylindrifolia at Huntington Botanical Gardens
© Candice Suter. Reproduced with permission.
Click here to visit Candy’s blog.

Euphorbia francoisii

Euphorbia francoisii is another plant endemic to Madagascar. Like so many species with narrow distribution, it is threatened by habitat loss. If you think my small plant isn’t much to look at, this description from the web site of the Cactus & Succulent Society of America may help you visualize its potential:

[T]he leaves and stems are the conspicuous features of these plants. With E. francoisii attractive cream color stems emerge from a geophytic caudex, or from a tangle of fat roots if the plant is a cutting. The branches sprawl gracefully in a random fashion making each plant a unique living sculpture. The uniqueness of each francoisii plant's leaf coloration and branch architecture is what I like most about this species. Every plant is a beautiful ever-changing, singular expression of Nature's wondrous and artistic hand.

My Euphorbia francoisii in a 4-inch container. All you can see right now are leaves.
Mature Euphorbia francoisii
© Tobias Wallek. Photo source:

  Euphorbia enopla

The next three euphorbias were cuttings I received from my friend Candy when I visited her last month. I stuck them in pots filled with dry succulent mix, and from what I can tell (there are signs of growth on some of the cuttings), they must have rooted. I’ll wait a few more weeks just to be sure, and then I’ll start giving them small sips of water.

LEFT: Euphorbia enopla
MIDDLE: Euphorbia leucodendron
RIGHT and BACK: Euphorbia flanaganii

Euphorbia enopla is a South African native. It forms colonies of short columnar stems that at first glance look a lot like cacti (no botanical relationship, but succulent euphorbias are often called the “cacti of the Old World”). The spines on Euphorbia enopla are very decorative and less lethal than they look.

Euphorbia enopla
Photo source: Wikimedia Commons

  Euphorbia flanaganii

Euphorbia flanaganii is one of the medusa-head euphorbias. Its sprawling stems resemble the serpents that ringed the head of Medusa. Check out this interesting article from Dave’s Garden on medusoid euphorbias.

My cuttings have definitely rooted—the brighter green “shoots” on the left are new growth.

New growth on my Euphorbia flanaganii cuttings

Here is a mature specimen of Euphorbia flanaganii at Ruth Bancroft Garden:

© Kelly Kilpatrick, Flora Dora Gardens. Reproduced with permission.
Click here to visit Kelly’s blog.

  Euphorbia leucodendron

Euphorbia leucodendron is a spineless shrub from Madagascar with cylindrical branches a little thicker than a standard pencil, hence its common name “pencil tree.” In its native habitat it is known to grow to 12 ft. but in cultivation 4-6 ft. is more typical. For most of the year, the branches are bare, but in summer tiny leaves appear on the growing tips (see here).

According to some sources, Euphorbia leucodendron is hardy to 25°F, so I may leave mine outside next winter. By then it will have fully rooted and put on quite a bit of growth.

Larger Euphorbia leucodendron in Candy “Sweetstuff’s” collection.
Click here to see more Google image results.

Euphorbia lactea ‘Rainbow Crest’

The regular form of Euphorbia lactea is an upright shrub or small tree up to 15 ft. in height (check out this impressive specimen). The crested form, sometimes indicated by the Latin word “cristata,” is a natural or environmentally induced mutation that causes the normally straight stems to twist and undulate. The result is often so bizarre that it borders on the ugly. But many succulent collectors are fascinated by such oddities, myself included.

There are many different crested forms of Euphorbia lactea, varying in color and shape. They are considered very difficult to grow on their own roots due to the lack of chlorophyll. For this reason, they are typically grafted onto hardier euphorbias such as Euphorbia neriifolia.

Euphorbia lactea ‘Rainbow Crest’ has become very popular. I bought mine at Lowe’s, but I’ve also seen beautiful specimens at IKEA.

Euphorbia lactea ‘Rainbow Crest,’ grafted on Euphorbia neriifolia
Euphorbia lactea ‘Rainbow Crest’

Discocactus araneispinus

The only cactus I’m overwintering inside is Discocactus araneispinus, a small cactus from Southern Brazil. Considered the easiest member of the genus Discocactus, it’s still not an easy cactus to grow. It wants to be kept at temperatures above 50°F and can rot easily if overwatered. At the same time, it needs some water, otherwise its fine roots will desiccate. Definitely a higher-maintenance plant than what I’m used to!

Discocactus araneispinus

At 2,103 words, this ended up being the longest single post I’ve written to date. No wonder it took me all week to finish it! I get very excited when I discover something new, and I hope some of my enthusiasm has rubbed off on you. Who knows, maybe you’ll end taking a walk on the weird side of the plant kingdom in the new year!

Thursday, December 22, 2011

Reshaping a disheveled bamboo

It goes without saying that I’m fond of the plants we have in our garden. After all, why grow something you don’t like? The same applies to our bamboos. We have about 30 different bamboo species in our garden. About half—the clumping bamboos--are in the ground, the others—running bamboos—are firmly contained in pots. While I like virtually all of them, I do have my favorites. One of them is chocolate bamboo (Borinda fungosa), a shade-loving clumping bamboo from the mountains of southwestern China. When exposed to the sun, its culms turn a lovely reddish brown, hence its common name.

I planted a chocolate bamboo in our Asian-inspired woodland garden in the fall of 2009. Read this post to see photos of what this area looked like at the time. In the following two years, what had started out as a spindly-looking plant grew into a beautiful specimen that has become the focal point of this corner of the backyard. I loved how everything looked this spring:

May 14, 2011

Over the course of the summer and fall, Borinda fungosa put out a lot of new growth. The thinner culms were weighed down by the leaves and started to droop heavily. By late fall, the granite lantern was all but invisible:

December 15, 2011. From this angle, you couldn’t see the lantern at all.

Doing something about this had been on my list of chores for a while, and last Sunday I finally got out the pruners. I cut down a few of the oldest (and thinnest) culms to open up the clump from the inside, and I removed the top 1/3 of the culms draping over the lantern. With a significant amount of weight gone, the culms returned to a more upright position, and the lantern became visible again. This is the result:

December 18, 2011 after pruning. The lantern is visible again!

Check out the next two photos. The left one was taken in May, the right one last weekend, after pruning. Balance has been restored.

Left: May 14, 2011
Right: December 18, 2011

One thing I’ve learned from growing bamboos—and the same holds true for many other types of plants: Don’t hesitate to trim growth you don’t like. Just because a plant grows a certain way doesn’t mean you have to live with it. Often all that’s required are small nips and tucks to get the look you want. You are in control. Exercise that right.

Sounds reasonable, you may say, but I’m often surprised by how hesitant people are to prune, trim or cut back a plant. It’s as if they are afraid of it. But I understand. I was like that, too, not all that long ago.