Opuntia Blog

Cacti of the Desert Southwest, book

Amazon.com offers a seemingly endless supply of books. Recently, I purchased a small book called Cacti of the Desert Southwest. I paid just about $4.00 plus postage to purchase the book used from a bookseller. Sometimes the new book price is just too expensive, but other times Amazon.com offers a discount. But, the new book price seldom beats the used book price. I’ve had nothing but success when I’ve ordered used books–no problems and delivery has been within a week or two.

Cactus Candy

Cactus candy is a novelty that is offered by a few candy stores. If you are brave (and want to handle an Opuntia cladode), you can make your own candy.

RECIPE
Use a sharp knife to remove spines and epidermis from 1 or 2 large Opuntia cladodes. Cut the skinned cladode into squares (about one-half to one inch). Pour cold water over the squares and soak overnight in a large excess of water at room temperature. Change the water and gently simmer the  squares until they are tender. Drain the squares and heat slowly in the prepared syrup until most of the syrup is absorbed; drain the squares. Roll the squares in sugar (powdered or granulated).

Syrup
Dissolve 3 cups of sugar in 1 cup of water over low heat until sugar is completely dissolved. Add 2 tablespoons orange juice and 1 tablespoon lemon juice. Use red food coloring if desired.

You can read more about cactus candy here. You can order cactus candy at the Cactus Candy Company.

Opuntia stricta seedlings, photo by Danny Green

Cactus seedlings generally can’t endure the conditions that mature plants can take in stride. Seedlings are sensitive to too much heat, sun, wind, and cold, as well as lack of water. Additionally, seedlings are more susceptible to grazing by insects and animals. Most cactus seeds never produce a cactus plant; they may germinate but very few live to produce a mature plant.

Many factors affect seed germination including temperature, moisture, and mechanical scraping of the seed. But, germination is just one aspect in plant reproduction. Seedlings must be able to survive and reproduce. Likely, many cactus seedlings only survive when special years occur, years with extra water or mild temperatures. Probably two or tree such years in a row are necessary.

One study showed that one in 20,000 Opuntia rastrera seeds survives to produce a plant in a grassland setting. The success rate is even worse in scrublands where one in 7,000,000 seeds produces a plant.

Opuntia ficus-indica, proposed for fighting desertification

Opuntia are considered a weedy species in many countries where they are not native, especially in the Mediteranean, Africa, Asia, and Australia. The plants have overrun farmlands and degraded natural habitats. However, at least sometimes, Opuntia are considered allies in the fight against the spread of deserts.

A newspaper reports that,

“The Federal Government has recommended that “Cactus Opuntia” plant should be used to combat desertification in Nigeria, Minister of Environment Mr John Odey has said.

He made the statement on Tuesday in Abuja at a sensitisation workshop on the “Utilization of Cactus Opuntia to combat desertification, organised by Interact Safety System Ltd.He said that the plant was selected, due to its potential in erosion control and land rehabilitation, especially in the arid and semi-arid zones of the country.”

I guess that one man’s poison is another man’s food. Read more about the use of Opuntia to fight desertification here and here.

The photo in the blog post shows a cactus seedling, grown under fluorescent lights and about 3-4 weeks old. The cotyledons are reddish, and sort of pointed to the left or right. They are not the typical cotyledons of a radish or other plant, rather, they are much reduced. The seedling is tiny, about 4-5 mm tall.

The “real” cactus is tinier still and sits at the top of the seedling; it is the white, fuzzy bit between the cotyledons. In time, the white, fuzzy bit will grow and become the cactus we are more familiar with.

Lobivia seedling, 3-4 weeks old

Escobaria vivipara

I’m confused about the differences between Coryphantha and Escobaria. I think that, as explained to me by various sources, the differences are small and perhaps difficult to detect. I understand that Escobaria flowers have fringed tepals, whereas the tepals of Coryphantha lack such fringe, but I don’t know if this is a hard rule or a soft rule.

Daiv Freeman (at CactiGuide) reports  that,

“The seeds of Escobaria are pitted (foveolate) unlike the crisscrossed (reticulate) seeds of Coryphantha. While the seeds are necessary to make a consistent distinction, other more generalized guidelines help differentiate Escobaria from Coryphantha. These other features include: a lack of extrafloral nectaries, fringed edges on the flowers, corking and falling off of tubercles with age and smaller, typically pink flowers.”

An article by Dicht and Luthy provides an examination of the thinking about Coryphantha, and how it differs from Mammillaria. I’ll probably have to spend more time growing the various plants in order to understand some of the subtleties. You can read more about Coryphantha/Escobaria in the Flora of North America. You can view photos of Coryphantha or Escobaria species at CactiGuide.

Coryphantha durangensis, photo from uknown source

Gymnocalycium bruchii flower

Gymnocalycium is represented by a number of cold-tolerant species, but only a few are known to be hardy to below zero F. Among these is G. bruchii, one of the few species that offsets easily. G. bruchii flowers are soft pink, or violet, or even nearly white.

Generally, Gymnocalycium are easy to cultivate, and G. bruchii is no exception. The plants bloom off and on during spring and summer and present no special difficulties. Like most globular cacti, Gymnocalycium don’t care for extended wetness or high humidity. G. bruchii should be hardy (if kept dry in winter) throughout most of USDA climate zone 6.

G. bruchii can be purchased from High Country Gardens or Mesa Garden. You can learn more about Gymnocalycium at the Genus Gymnocalycium.

I hope a reader can help me identify this cactus; I think it is a type of Mammillaria. I don’t usually buy unnamed cacti, but this one was on sale for about $1.50 at Home Depot, or Lowes, or a similar megastore. There were several cacti and I though I’d try some out for cold hardiness.

I bought the plants when night dipped to about 35 F, and I left them on my patio for weeks while the nights grew progressively colder. When temperatures dropped to 20 F, I checked the plants and they were fine. Then, I left them out when temperatures dropped to about 15 F, and finally to about 10 F. Two cacti died, and the one depicted here survived. I don’t think the temperature was really 10 F on the patio because it is a covered patio and because the little cactus plant was next to the house wall, but it got pretty cold.

Unidentified cactus

Neobuxbaumia scoparia, click on photo for original source information, photo by Daiv Freeman

I don’t know much about Neobuxbaumia, or how (in particular) members of the genus differ from other columnar cacti. There are 8-10 species of Neobuxbaumia and species in Pseudomitrocereus and Rooksbya have been folded into Neobuxbaumia by some authors.

At least some Neobuxbaumia are bat pollinated, and possibly all of them are. The flowers are generally large and held “outwards” so that bats may approach them. Also, some Neobuxbaumia, or all, open at night.

Neobuxbaumia are reported in Mexico and Peru, and probably places in-between. The photo at the left is from the CactiGuide Neobuxbaumia page, you can also find out more about Neobuxbaumia here.

Opuntia trichophora, north-central New Mexico, about 5,200 feet elevation

If you look in the seed catalog of SuccSeed Nursery, you can find some cacti from 3,000 or 4,000 meters in the Andes mountains. If you do the conversion, 4,000 meters is equal to abut 13,200 feet elevation, which is about 2 1/2 miles altitude.

Some of the Opuntia on this page were photographed by Daiv Freeman (CactiGuide.com) at about 10,500 feet in the White Mountains of California. Again, if you do the math, that is about 2 miles elevation. More commonly, cacti can often be found between 5,000 feet and 7,500 feet (1 mile to 1 1/2 miles high).

I think most cacti are found growing between sea level and several thousand feet, but there are a number of cold and dry areas of the New World where cacti can be found. The cacti may not be numerous or prolific, but they grow at amazing altitudes.

The various genera that include high-altitude cacti include Echinopsis, Opuntia, Rebutia, Lobivia, Pediocactus, Escobaria, Sclerocactus, Tephrocactus, and many more.

Cleistocactus smaragdiflorus, photo by Craig Howe

 Cleistocactus smaragdiflorus grows in Argentina. I don’t know much about the species but liked this photograph an email friend forwarded to me.

The genus Cleistocactus might have 4 dozen members, or perhaps 100 members; it depends upon which author/scientist is reporting on the genus. This ambiguity may be due, in part, because other genera have been combined into Cleistocactus in recent years. Or, perhaps, the confusion is because there is disagreement about which genera to fold into Cleistocactus.

Notice the closed, or nearly closed, red flowers. The color and the shape suggests a bird-pollinated plant to me. You can read more about Cleistocactus here.

Delosperma basuticum, 'White Nugget'

I’ve looked around the Web, trying to find places to order various plants. I didn’t find many that offerred Delosperma basuticum ‘White Nugget’. But, I did find a couple of places, one of them is Laporte Avenue Nursery in Colorado. They offer a number of cold-hardy and unusual plants (many rock garden items).

They actually offer a variety of Delosperma plants, including one from Yemen (D. harazianum [currently unavailable]). The various Delosperma plants seem to cost $5.00, plus shipping and handling.

A quick check of their Web site showed they also offer Opuntia polyacantha, O. aurea, (listed as O. basilaris v. aurea), and some sedums. The Web site is well designed and easy to use.

Stuart in the snow

I live in Maryland and, since leaving Texas, I haven’t had an outside garden. So, I grow cacti on my patio, or in the house under lights (in winter). Next year I hope to have a few more plants in pots that I can leave out for the winter (or most of the winter). 

We’ve had a lot of snow recently in Maryland, and it’s just as well I don’t have many plants outdoors because I wouldn’t be able to find them. There was about 2 foot of snow before Christmas, and recently another 30 inches. More snow is forecast for tonight.

I don’t have a photograph of cacti in the snow, but I do have a photo of my dog in the snow. He was happy to get into the house after the picture was taken. You can find actual pictures of cacti with snow here, and here.

Garden Soil

A brief discussion on a cactus email list recently got me thinking about potting soil for cacti: to sterilize or not to sterilize. This is a topic that stirs passions.

For what it’s worth, I don’t use sterile soils in my potting mix, but I use “clean” ingredients. Thus, for small amounts of soil I use packaged potting soil (typically a loam with compost) as a base. I mix the base with coarse sand and with perlite or pumice. For general use I add each part in equal volumes. Because I use packaged and/or composted ingredients, I don’t worry about insect eggs or fungal inoculum, and I don’t heat treat the ingredients.

However, if I used soil right from the garden (as in the photo) I’d be sure to bake it for 2 hours or more at 200 degrees F (about 93 C) to kill insects and some pathogens. If I threw in a handful of compost (from the compost pile) and I wouldn’t bother to heat treat the compost because I’m happy with the “cleanliness” of composed ingredients.

Other folks feel differently about the matter and don’t take special efforts to kill organisms in their potting soils, heating or composting. I guess that, whatever works for you is what you should do.

Spiderwort with Opuntia polyacantha

Think of Nebraska when you think of cactus country. Opuntia fragilis is found in Nebraska, as well as Escobaria missouriensis. And for sure, you can find O. polyacantha. All three species are found well into Canada.

This image shows spiderwort (Tradescandia sp.) growing with Opuntia polyacantha in Nebraska. For more images of Cacatus Country in Nebraska, click here. The images were taken by Daiv Freeman at CactiGuide.com.

Othonna capensis

Othonna capensis is not an ice plant, but you could be forgiven for supposing it was. It has succulent little leaves that call an ice plant to mind, and both are from South Africa. And the cheery yellow flowers seem a bit ice plant-like.

However, O. capensis, also known as little pickles, is a member of the sunflower family. It is hardy into USDA climate zone 5 and loves a sunny spot.

You can buy O. capensis from Shoal Creek Succulents.

This lovely photo came labeled as Trichocereus formosus. So, my question is, what is the name for this plant when it is considered as a member of Echinopsis?

Note added later: Trichocereus formosus is known as Echinopsis formosa. However, a reader points out that the plant in the picture is probably a hybrid.

Unidentified Echinopsis

Echinocactus horizonthalonius

These big (grapefruit-sized) cacti were growing in the Big Bend region of Texas. They are Echinocactus horizonthalonius, a western relative of the Texas horse crippler cactus (Echinocactus texensis). E. horizonthalonius is also a relative of the Mojave Desert E. polycephalus.

E. horizonthalonius typically grows in limestone-derived soils with very good drainage.

Many forms of this cactus are hardy to USDA climate zone 6, but they resent over watering. E. horizonthalonius is common enough in far West Texas and south-central New Mexico.

This coachwhip snake was photographed in the Big Bend region of Texas.

Coachwhip snake

The Big Bend area of Texas is an amazing place, with plants and wildlife in abundance. These vultures were photographed by a friend. It is not clear what type they are.

Vultures in Big Bend, settling in for the night

Delosperma seedlings, true leaves showing on middle plant

A few weeks ago I reported that my hardy Delosperma seedlings had germinated. They’ve been pretty slow growing since they popped out of their seeds; I think they were making roots. But, now they are growing a bit more and some are showing their first true leaves.

The true leaves are emerging from between the 2 cotyledons, sticking straight up, sort of like bunny ears.

The plants are doing fine under the fluorescent lights. I continue to grow them at room temperature with about 14 hours of light per day.

Coryphanthus echinus, photographed in Big Bend region, Texas

Coryphanthus echinus is a globular cactus that seldom offsets; it has bright yellow flowers. Some plants may have areoles with a porrect central spine, whereas other areoles lack such a spine. The plants are generally easy to grow and have a reputation of being cold hardy (to USDA climate zone 6).

You can read more about C. echinus here. You can purchase C. echinus from High Country Gardens.

Ariocarpus fissuratus, photo by Craig Howe

Parts of Texas are home to Ariocarpus fissuratus, a plant wonderfully adapted to harsh conditions. Its gray-green (or brownish) color help it hide among rocks where it grows (typically in calcareous soils). Much of the plant is, in fact, underground as a subterranean storage organ–a factor that also helps Ariocarpus to hide.

Ariocarpus has been placed in various genera over the years, including:  Mammillaria, Anhalonium, and Roseocactus.  You can read more about A. fissuratus here and here.

Carnegiea gigantea

There is only one member of the genus Carnegiea, C. gigantea (the saguaro cactus). It is widely recognized around the world as a symbol of the American West, though it also occurs in Mexico. In the United States the plant is essentially found only in Arizona even though it calls to mind the whole West.

C. gigantea can reach 50 foot-tall, but individuals are often shorter than that. The ribs of the cactus provide an accordion-like architectural feature to the plant and also allow it to expand in size. The plant may expand when it absorbs water after a rain.  The trumpet-shaped flowers are white on the inside, but the floral tube is green on the exterior. The flowers are pollinated by bats. The edible fruit has been used to make wine and jams.

C. gigantea may be distantly related to Neobuxbaumia and Pachycereus; the three genera produce similar alkaloids.

You can read more about C. gigantea here, and here. You can purchase seeds or small plants of C. gigantean from Mesa Garden Nursery.

Aztekium hintonii

There are just two species of Aztekium, A. hintonii and A. ritteri. They are small, globular plants with pink or white-pink flowers. The two species grow on gypsum cliffs in Mexico and are quite limited in natural occurrence. Each species is known from its own (single) location in the state of Nuevo Leon.

Boedeker reported A. ritteri in 1928 and it was over 62 years later that A. hintonii was reported. Both plants are fairly small, and with limited occurrence. It is understandable that they were not discovered early in cactus discoveries.

You can read more about Aztekum here and here.