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Along with other articles, columns and club updates, each monthly issue of the Henry Shaw Cactus Digest includes an article or two on members' favorite cactus and succulent species. The articles typically include photos and facts on the plants' natural origins and distribution, growing conditions, common and scientific names, care and cultivation tips, and helpful hints for encouraging flower production.
Follow the links below this month's offering(s) to enjoy previous Plants of the Month or click to read a sample of the HSCSS Digest in PDF format.
November 2017 -- Huernia
By Rey Gonzalez
About a year and a half ago, while shopping for some plants, I came across a beautiful species from the genus Huernia. Even though I prefer growing desert plants, the flowers were so captivating, I ended up taking one home.
The genus finds its habitat in the low altitudes of Zimbabwe, Botswana, Mozambique and South Africa. One of about 64 Huernia species, H. zebrina is one of the most beautiful and very popular in cultivation as a result of its odd blooms. This species produces amazing five-pointed, starlike yellow blooms usually patterned with wine-red zebra stripes that vary conspicuously in color intensity.
It also has a raised, glossy dark-red ring or "annulus" around the mouth of the corolla tube. The peculiar resemblance of the annulus to a Life Saver candy gained this species the commonly known name of "lifesaver plant."
The blooms last for a week or so -- and no, they don't stink, as some may think. The flowers have four-sided stems with soft teeth along the edges. In lower-light situations, the stems are deeply green, but they attain a reddish tinge in full sun.
I had mine hanging in the greenhouse getting full sunlight almost all day, but I noticed the plant was being stressed under the searing heat and light. I moved it to a place in the greenhouse where it gets partial sun in the morning and afternoon, but shade during the hottest hours of the day. Since then, it has expanded considerably, and from late spring to late fall, it is a spectacle to see all the flowers coming out.
When planting huernias, choose a well-draining container, preferably one that is unglazed and will allow evaporation of excess moisture. If grown inside, try an eastern or western window that is bright most of the day, but doesn't experience the hottest sun rays.
A sensible watering schedule is key to caring for huernias. Probably one of the main reasons for failure is that overwatering of this huernia is very easy. As with most succulents, the plant is prone to rot if it is too wet, but it does need supplemental water during its growing season. In winter, the plant hardly needs water at all -- just once per month on average, as it is mostly dormant. In spring through summer, water the plant when the soil is dry to the touch.
Another important part of this genus care is temperature. If you grow the plant outside, it should be moved indoors when temperatures drop to 50 degrees F. Pests are rarely a problem, but occasionally mealy bugs can become a concern. The only method of propagation, as far as I know, is by cuttings. The plant roots easily and produces flowers very quickly.
If you're a plant enthusiast on the lookout for an unusual and amazing specimen, H. zebrina is a very fun and manageable plant to add to your collection. Everybody who comes to visit me and see the greenhouse is always in awe of the magnificent blooms on display.
Fun fact: Last fall, my plant had a bizarre visitor. When I was watering for one of the last times, I noticed a garden snake had found shelter inside the greenhouse, avoiding the dropping temperatures outside by wrapping itself around the stems of my huernia.
The Huernia Page -- http://www.succulent-plant.com/families/apocynaceae/asclepiadaceae/huernia.html
The Encyclopedia of Succulents -- http://www.llifle.com/Encyclopedia/SUCCULENTS/Family/
Huernia Cactus Care: How to Grow a Lifesaver Cactus -- https://www.gardeningknowhow.com/ornamental/cacti-succulents/huernia/
November 2017 -- Welwitschia
By Bob Williams
After this year's HSCSS show and sale in July, Marge lamented the fact that her educational poster on Welwitschia was the only one without a live sample plant in the display. While attending the CSSA convention in Phoenix a few weeks later, that situation was remedied.
We now have a Welwitschia mirabilis that, with proper care, could become 4 feet tall with a "wingspan" of 6 feet and have a 30-foot tap root. When these dimensions are met, though, this long-lived plant will be cared for by our great-great-great-great-great-grandchildren.
A good thing about W. mirabilis is it never sheds any leaves; it only grows two during its entire lifetime. Forget to water this month? No problem. It can survive on very little water, 0.5 inch per year in the wild. In a wet year, it might see only 4 inches of water.
The first welwitschia plant was discovered by Austrian botanist Friedrich Welwitsch in 1860 in the Namib Desert in the southern part of Angola. The plant was named after Friedrich in recognition of his successful botanical research and because he found and collected it first. The story goes that he was so overcome by his find that he knelt next to it and simply stared at it in amazement.
The only member in the family Welwitschiaceae, W. mirabilis is one of the more bizarre plants around. Technically, this plant is considered a tree and not a succulent. Experts have a difficult time classifying it.
W. mirabilis is considered a caudiciform, but is not included in the majority of the literature on "fat plants." Tree people consider it an upside-down tree, with the leaves acting as the roots and the large tap root as the trunk. Ernst van Jaarsveld, an expert on W. mirabilis, calls it a terminally truncated caudiciform that starts out as a tree.
Welwitschia is one of the longest-living plants around. Average life expectancy is 400 to 600 years, and 1,000-year-old plants are common. The oldest plants are thought to be over 2,000 years old. They are considered a living fossil, and can be traced back to the Jurassic Period some 200 million years ago.
Welwitschias are native to a strip of land about 50 miles wide and 500 miles in length along the coast of the Namib Desert in Namibia and southern Angola. They occupy dry riverbeds and occasionally grow on rocky outcrops. High heat and little rainfall are the norm. But because of a cold coastal ocean current, this area also gets regular fog, which adds almost another 2 inches of annual precipitation. The fog develops during the night and usually evaporates by about 10 a.m.
The plants' leaves are broad and large, and droop downwards. This is an ideal way for them to water their own roots with water collected by condensation. A welwitschia taproot can be up to 30 feet long, allowing it to also reach underground water.
W. mirablilis can be simply described as two leaves, a stem base and a taproot. From seedlings, the first leaves continue to grow horizontally from the stem base for the life of the plant. Weathering eventually causes the thick and leathery leaves to fray and split. This prevents the leaves from extending across the desert ground and serves a useful purpose. The split leaves curl around the plant and provide shade to the base and taproot.
Welwitschia is a gymnosperm that reproduces by means of seeds in cones that are not visible until maturity. After pollination by insects, male plants produce small flowers containing pollen and nectar along their cones. The flowers open in succession over an extended period, which encourages cross-pollination.
Cones from female plants reach maturity about nine months after fertilization. The cones open up and expose the seeds, which like pinecones, have large, papery "wings." Seeds are dispersed by the wind and are viable for years, but few geminate. Some are lost to fungus, while most serve as food for small animals.
The plant is valuable to the wildlife in the desert. W. mirabilis provides an important source of moisture and nutrients for animals such as oryx, springbok zebras, black rhinos and other animals in times of extreme drought. The animals chew the leaves, sometimes down to the base, but the leaves grow out again. Gray's larks have been seen nesting on or under W. mirabilis. Snakes, lizards and insects use the plants for shelter.
In my research, I found welwitschias are not extremely hard to grow, although growing from seed seems tricky. When growing from seed, germination occurs in one to three weeks. Keeping the soil mix damp is key. In habitat, germination only occurs after several days of rain. A sign of success is the appearance of two cotyledons, which are initially pink but become green. These look like leaves, but are not the two permanent leaves.
Initial growth is rapid, particularly of the taproot. It is essential that seedlings in a shallow tray are planted out as soon as the cotyledons appear. Take care when transplanting, though. If the root tip of a plant is damaged, the seedling will die. Keep seedlings' soil moist and use fungicide during the first season. Higher temperatures and sunlight help them grow faster.
After the first year, it looks like things get easier. Even though they live in a dry climate, keep the soil for seedlings moist for the first two or three years. During the summer, they like it hot and sunny. Fertilize monthly during the growing season.
For the next year or two, water every other week and fertilize on a regular schedule. Cut back watering in the winter, keeping the plants in a warm, sunny place. They are not affected by many pests or diseases.
Since they have long taproots, pot selection for maturing plants is different than for other succulents. Their pots should be taller than wide. I saw one site where a welwitschia was planted in clay drainage pipe. As the plant grew, the "pot" was replaced by bigger-diameter pipe with wire screen taped around the bottom.
Welwitschias are not endangered in the wild and are fairly common. In both Namibia and Angola, large populations are found in national parks that offer some protections. In Angola, those outside the parks are found in areas where civil war was prevalent. These plants tend to be protected by land mines that remain in the ground.
There is quite a bit of information about welwitschias and sources for plants and seeds on the Internet. An informative and entertaining site can be found at http://www.info-namibia.com/activities-and-places-of-interest/swakopmund-surrounds/welwitschia-mirabilis.
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