Corchorus siliquosus – Slippery Burr

Corchorus siliquosus bears an elongated capsule with four toothlike appendages at its apex (note the unripe capsule in the lower left side of the image).

Slippery burr, Corchorus siliquosus, is a native short-lived perennial or subshrub recorded from south Florida in Collier, Miami-Dade, and Monroe counties, including the Florida Keys. It is an inconspicuous plant due to its thin, erect stems with short side branches and small leaves and it tends to blend in with the surrounding vegetation. Although normally growing 1–3.3 feet (0.3–1.0 meters) tall, it can flower and set seed when only a few inches tall. At about 0.4 inches (10 millimeters) wide, the flowers are too small to make a showy display but they are extremely attractive due their brilliant yellow color and numerous stamens. The flowers are ephemeral, opening around 2:00 or 3:00 P.M. and closing the next morning, but large, healthy plants will produce numerous flowers over a long period in the summer and extending into autumn or winter. The flowers are soon followed by elongated capsules 2–3 inches (5–8 centimeters) long filled with numerous small black seeds. Unfortunately, the charms of Corchorus siliquosus in flower are soon diminished by the conspicuous, numerous, and rather unsightly seed capsules. However, since plants tend to decline after a year or two, gardeners must let it go to seed if they wish to have it persist from one year to the next.

Corchorus siliquosus is a somewhat weedy plant of open, disturbed sites. This is both good and bad as far as its cultivation is concerned. It is a good thing because, like most weedy plants, it is very easily cultivated in just about any sunny spot with well-drained soil. It is bad because it produces a prodigious number of self-sown seedlings and can soon overtake a large sunny garden bed if larger or more aggressive plants are not present to keep it in check. In spite of its weedy nature, I enjoy its little flowers in the late summer and autumn garden, where they shine with a fiery glow on crisp, clear, sunny afternoons and thus always keep one or two plants going in the yard. Propagation presents few problems and Corchorus siliquosus may be easily grown from cuttings. It is also easily propagated from seeds but patience is sometimes required since the seeds can sometimes be slow and erratic in their germination.

There are three other species of Corchorus in Florida, one other native and two that have been introduced from the tropics. Corchorus siliquosus is distinguished from all other species in Florida by its long seed capsules that abruptly end in four small, toothlike protuberances at the apex. Corchorus siliquosus is a plant of the North American tropics from southern Florida and the West Indies as well as from Mexico to Panama. Although today it is regarded as native to Florida, John Kunkel Small regarded it as naturalized from the West Indies. There is a possibility that both views are correct with plants in the Florida Keys and Everglades National Park being native and those from disturbed ruderal sites elsewhere in Florida representing inadvertent introductions resulting from human activities.

Image and text © 2012 Rufino Osorio

Solanum tuberosum – Potato

I kept two potatoes too long in the fridge and they began to sprout. This past weekend, I planted them in the yard to see what happens. Most likely a horde of Florida fungi, nematodes, and insects will put a quick end to them; however, I might get lucky and get a chance to add the photographs of a potato plant and its flowers to my collection of plant images.

Image and text © 2012 Rufino Osorio

Symphyotrichum georgianum – Georgia Aster

This exceptionally deep violet-purple form of the Georgia aster is the cultivar 'N3 Purple Haze'.

Georgia aster (Symphyotrichum georgianum) is a colonial, rhizomatous perennial with flowering stems 1.5–3 feet (50–100 centimeters) tall. It is listed by the USDA as occurring in Alabama, Florida, Georgia, Louisiana, North Carolina, and South Carolina. In Florida, it is a rare plant that is listed as occurring only in Leon County by the Atlas of Florida Vascular Plants.

On March 17, 2006, I acquired a small plant of the deep violet-purple cultivar 'N3 Purple Haze' and planted it in a sunny site in well-drained sandy soil. It quickly spread by way of underground rhizomes to form a patch that covered about 1.5 square feet (0.4572 square meters). To my surprise, the colony has never grown beyond those 1.5 square feet even though there are no obstacles or larger plants preventing its spread. Thus far, it has not been attacked by the aphids, caterpillars, mealy bugs, scales, nematodes, grubs, or viruses that prove so troublesome in south Florida.

New stems of Georgia aster emerge in early spring.

Georgia aster flowers abundantly and spectacularly but it is among the last of the wildflowers to bloom in my garden and begins to flower at the end of October or the beginning of November. The only other wildflower in my garden that blooms later are my clones of Symphyotrichum concolor (eastern silver aster) from Miami-Dade County, which do not flower until the end of November or even December. After flowering, the stems dry up and I remove them. Unlike some asters, the stems of Georgia aster tend to recline, or even lie on the ground, with age. Gardeners who desire a more formal appearance can trim back the plant in mid-summer, a treatment that results in shorter, more erect flowering stems.

Like most rhizomatous perennials, Georgia aster is easily propagated by splitting off and potting up new growths in the spring. My single plant has never set viable seed, which indicates that Georgia aster is self-sterile. This year I've acquired a second clone and I'm hoping to obtain viable seed next year. The new clone has flowers of the typical color for the species, deep blue rather than purple-violet, and I'm hoping that, by crossing the two, I will get progeny whose flowers will come in a range of blue, violet, and purple colors. Craig Huegel has images of plants with the typical deep blue flowers at his blog, Native Florida Wildflowers.

Images and text © 2012 Rufino Osorio

Is Lantana depressa Sphingophilous?

Lantana depressa is a dwarf, evergreen, short-lived shrub that bears small but numerous bright yellow flowers. It is a state-listed endangered species that occurs only in Miami-Dade County. The flowers are attractive to butterflies and it is sometimes grown as a nectar plant in butterfly gardens.

On Tuesday, November 6, 2012, at approximately 5:30 PM (Eastern Daylight Saving Time) I was at the local Home Depot and noticed a large, brown sphinx moth repeatedly and persistently visiting the flowers of Lantana depressa. I purchased two plants and, after getting them home, I noticed for the first time that the flowers were fragrant. The fragrance was not powerful but it was distinct and clearly noticeable. It was sweet and pleasant but was unlike any other floral scent I have ever experienced. The next day, I tested the flowers to see if they were fragrant during the day but the scent was almost undetectable.

Based on these observations, it appears that Lantana depressa employs a dual pollinating strategy: psychophily (butterfly pollination) during the day and sphingophily (sphinx moth pollination) during the night. The presence of a distinct sweet odor that intensifies at night is a classic sign of sphinx moth pollination. Also, an adaption to sphinx moths as pollinators might explain an important distinction between Lantana depressa and the weedy, non-native, and invasive Lantana camara. The latter has flowers that open up one color and then fade to another. This allows pollinators to readily distinguish fresh, nectar-filled flowers from older flowers as well as creating a more easily noticeable floral display. In Lantana depressa, older flowers do not change color or else become merely a slightly darker shade of yellow. If Lantana depressa is transitioning to or has become adapted to sphinx moth pollination, this would explain the color constancy of the flowers since a difference in color between new and older flowers would not be perceptible to nocturnal sphinx moths.

Before ending this post, I would like to point out another interesting observation made at the Home Depot on November 6. Growing immediately adjacent to the pots of Lantana depressa were numerous cultivars of Lantana camara. The latter bore innumerable fruits in all stages of maturity whereas not a single fruit was to be seen on the plants of Lantana depressa. Although Lantana depressa will cross-breed with, and be genetically swamped by, Lantana camara, it appears as if that particular Home Depot clone of Lantana depressa was both self-sterile and not interfertile with the adjacent clones of Lantana camara.

Image and text © 2012 Rufino Osorio

Cuttings

The image above shows my preferred technique for propagating plants from cuttings. I use small plastic cups that are 2 inches (5 centimeters) wide across the top. After inserting the cutting in the soil, I loosely wrap it up with plastic to maintain high humidity and the cuttings are placed in a frosted east-facing window. This provides bright light, which stimulates the cuttings to root more readily, while avoiding excessive sunlight that would scorch or bake the cuttings. Except for woody, hard-to-root cuttings, I do not use any rooting hormones.

Once the cuttings are well rooted, I'll harden them off by removing the plastic wrap and slowly acclimating them to full sun. Then I'll move them into bigger pots (unlikely) or plant them directly in the ground (much more likely). I prefer to place small cuttings like these into the ground for three reasons. First, the small pots, with their equally small quantities of soil, use up far less resources than larger pots. Second, they are much more easily handled than larger pots and create far less of a disturbance in the garden than does the planting of a larger plant. Lastly, small young plants adjust better to life in my sandy South Florida soils than do large plants. Often, large plants originally flourish but eventually perish when their roots, accustomed to living in a large pot of rich, organic potting soil, fail to adjust to growing in Florida sand. I also like this system because both the plastic pots and the plastic wrap can be reused indefinitely.

For curious readers, the plants above are, from left to right: Plectranthus parviflorus 'Sapphire Dream', which is being rooted in water; two cuttings of Calamintha coccinea (synonym: Clinopodium coccineum); and two cuttings of Piloblephis rigida 'Juniper'. All three are members of the mint family (Lamiaceae). The Plectranthus is a variegated cultivar of a plant originally native to South Africa and Swaziland. The Calamintha is native to Alabama, Florida, Georgia, and Mississippi. The Piloblephis is native to peninsular Florida and the Bahamas. Piloblephis rigida 'Juniper' is a cultivar originating from plants growing wild in Palm Beach County that has a very dense and crawling growth habit with mature plants forming a solid groundcover only a few inches high and resembling a prostrate juniper.

Image and text © 2012 Rufino Osorio

A Xeric Garden

A dwarf agave with rosettes less than 12 inches wide toughs it out in pure Florida sand. My guess is that it is one of the many forms of Agave potatorum. The genus Agave is native to the New World from the southern United States to South America but it reaches its greatest diversity in Mexico.

I have been watching the endeavors of a local gardener with keen interest. Apparently having grown weary of tending a lawn, this gardener removed all grass from a small front yard and is growing tough desert plants. Although markedly different from the typical pseudo-tropical south Florida garden, it shares with such gardens the presence of plants from far-flung regions of the world and a lack of any native plants.

Euphorbia tirucalli is native to Madagascar and is characterized by a highly toxic and caustic sap. It has also been linked with Burkitt's lymphoma, a typically rare cancer that tends to be associated with regions where Euphorbia tirucalli is extensively used as a hedge plant. The pictured plant is a cultivar with brightly colored new growth called 'Sticks on Fire.'

An Opuntia species with a growth habit similar to the native semaphore cactus (Opuntia corallicola); however, the native semaphore cactus is markedly spiny and tends to have pads of a lighter green color.

The so-called Madagascar palm is not a palm at all. It is Pachypodium lamerei, a spiny-stemmed succulent from Madagascar in the oleander family (Apocynaceae). It should be handled with care since the spines are extremely sharp and can cause severe injuries or infections if they happen to impale the knuckles or joints of the fingers.

This aloe is very similar to Aloe arborescens from Africa; however, the rosettes are much smaller than that species. I am guessing that perhaps it is a small-growing hybrid of Aloe arborescens.

Images and text © 2012 Rufino Osorio

Amelia's Smarty Plants

Jatropha integerrima is a drought tolerant shrub from Cuba in the euphorbia family (Euphorbiaceae). It is very common in south Florida gardens and is often recommended for butterfly gardens.

Amelia's Smarty Plants is a full service neighborhood garden center located at 1515 North Dixie Highway in Lake Worth, Florida (phone number: (561) 540-6330). Plants in stock are very diverse and include a wide variety of subtropical and tropical ornamental plants as well as flowering annuals, herbs, and a diverse selection of Floria native plants. Below are a few photographs that I took on a recent visit.

Justicia betonica, the white shrimp plant, is native to Africa and has unassuming flowers peeking out from white, green-veined bracts; however, the flowers apparently produce ample nectar since they are avidly visited by honeybees. Like many shrimp plants in the genus Justicia, it has plain green leaves and is vegetatively nondescript.

Nerium oleander 'Variegata' is a variegated oleander with brilliant chartreuse leaves that gradually develop varying amounts of green. The flowers are blousy pink things that I do not find particularly attractive. Oleander is now cultivated throughout the subtropics and tropics of the world but was originally native to western Asia and the Mediterranean region of Europe and northern Africa. Formerly regarded as non-invasive in the United States, it is now listed as invasive in Arizona and it is escaping to floodplains and riparian zones in California.

The pink trumpet vine, also known as Zimbabwe creeper (Podranea ricasoliana), is an African vine in the bignonia family (Bignoniaceae). It has escaped cultivation in a few counties in Florida. Such occurrences should be carefully monitored to see if, like many tropical vines, it has invasive tendencies.

This is a hybrid Tecoma and the flower color and flower form leave no doubt that it is in the same family (the Bignoniaceae) as the native trumpet creeper (Campsis radicans). And like the native trumpet creeper, it is attractive to hummingbirds. The genus Tecoma is native to both the New World tropics as well as to Africa.

Chrysanthemum ×morifolium, the garden chrysanthemum, was domesticated in China where it was originally used as a culinary herb and tea plant. It generally does not survive south Florida's hot and humid summers; however, many garden centers carry them as short-lived decorative flowering plants to brighten the autumn garden. The plant pictured here has pom-pom flowers, one of 13 classes into which chrysanthemum flowers are categorized.

This showy chrysanthemum with brilliant autumnal colors has semi-double flowers, another of the 13 classes into which chrysanthemum flowers are categorized.

Images and text © 2012 Rufino Osorio

Zinnias etc.

Cosmos sulphureus, a short-lived annual native to the American tropics, is attractive to many insects.

UPDATE: The United States Department of Agriculture Plants Database lists the scientific name of the common garden zinnia as Zinnia violacea; however, the Atlas of Florida Vascular Plants uses the name Zinnia elegans and lists Zinnia violacea as a nomen rejiciendum (a rejected name) under the rules of the International Code of Nomenclature for Algae, Fungi, and Plants. As a result, the name Zinnia elegans is used in this blog post.

I visited the garden of Robert Hopper today and found that his cottage garden annuals were in full bloom. Further north, these annuals would be planted in the spring to flower in the summer. Here in south Florida, they are planted in the autumn to flower throughout the winter.

Some of the plants in flower included Cosmos bipinnatus, Cosmos sulphureus, Portulaca grandiflora, Salvia farinacea, Zinnia angustifolia, and Zinnia elegans. Except for Salvia farinacea, which is a perennial native to Texas and New Mexico, these plants are all annuals native to Central or South America. To date, none have exhibited invasive tendencies in the United States and all have showy flowers that are attractive to numerous native pollinating insects as well as to honeybees. The plants of Zinnia elegans apparently came from open-pollinated seeds Burpee's Cut & Come Again Mix and a wide variety of colors and forms, including singles, semi-doubles, and doubles, were present in the garden. Fully double zinnias have little or no wildlife value but zinnias with single and semi-double flowers are irresistible to honeybees, native bees, hover flies, skippers, butterflies, hawk moths, various flower-visiting wasps, and hummingbirds.

Zinnia elegans, the common garden zinnia, tends to be short-lived in south Florida and is subject to diseases and pests that disfigure the leaves such as viruses, downy mildew, and leaf miners. It was originally native to Mexico but can now be found in gardens nearly throughout the world. If allowed to go to seed, it can persist in garden settings from self-sown seedlings but it eventually reverts to its wild form and plants with double, pom-pom-like flowers are replaced by plants with single or semi-double flowers. It also tends to escape from cultivation, especially to roadsides and other areas kept free from competing vegetation by natural disturbances or human activity; however, it generally does not persist for long.

Below are images of a few of the plants in Rob's garden as well as a rather extensive gallery of some of the many variations of Zinnia elegans that sprung up in his garden.

Angelonia angusifolia soon dies in my garden but this attractive dark purple form has proven to be long-lived in Rob's garden. Originally native to Mexico and Guatemala, it is now widespread in the tropics as an escape from cultivation.

Landoltia punctata has formed a solid cover on the surface of a small aquatic garden in Rob's yard. It is frequently misidentified as a native duckweed; however, no North American records are known prior to its occurrence in 1930 in a goldfish pond in Kansas City, Missouri, and it is now known to be native to southeast Asia and Australia.

Zinnia angustifolia is a small annual that produces numerous brilliant white, yellow, or orange daisies. It does not last long in the garden since it tends to quickly flower and seed itself to death. Native to Mexico, it has been bred with Zinnia elegans to produce a hybrid zinnia that has the disease resistance and abundant flowers of the former with the large flower size and range of colors of the latter.

All subsequent images are of the various forms of Zinnia elegans that sprung up in Rob's garden.

Zinnia elegans with flowers of an unusual burnt orange color. In the upper right, one can see the attractive flower buds typically found in garden zinnias. These are globose and have green bracts with black-rimmed margins.

Plants of Zinnia elegans with single flowers, such as this one, have the most wildlife value since the yellow disc florets provide plenty of pollen and nectar.

A plant of Zinnia elegans with semi-double flowers.

Plants of Zinnia elegans with fully double flowers, such as this one, lack the pollen- and nectar-bearing disk florets and have little value to insect wildlife.

The discoloration of the leaf in the upper right hand corner of the photograph is the result of leaf miners.

The flower heads in this photograph and the following two photographs are displaying symptoms caused by the Bidens mottle virus, which causes deformities of the leaves as well as color breaks in the flowers.

Color breaks, such as those shown in this photograph, are a symptom of the Bidens mottle virus. The virus is spread by aphids and is hard to avoid since Bidens alba, a common and abundant weed of south Florida, serves as a reservoir by which the virus can readily infect garden plants.

The effects of Bidens mottle virus are sometimes dramatic and colorful as in the above example; however, if such plants are not destroyed they will act as a reservoir for the virus and allow the virus to spread to other plants.

A honey bee, Apis mellifera, on Zinnia elegans. The foliage in the background, as well as in the flower buds in the lower left hand corner, belong to Cosmos sulphureus.

The spiny branches visible in the photograph belong to Acacia pinetorum, a small, shrubby, native acacia that becomes a mass of fragrant, yellow, globose flower heads in the spring.

Images and text © 2012 Rufino Osorio

Symphyotrichum oblongifolium 'Raydon's Favorite'

Symphyotrichum oblongifolium 'Raydon's Favorite' is a big bang bloomer that covers itself in flowers in the autumn.

Every year since 1996, Symphyotrichum oblongifolium 'Raydon's Favorite' reliably flowers in my garden towards the end of the year in late October and November. The common name is "aromatic aster" and it is based not on the fragrance of the flowers but rather on the aromatic glandular hairs of the bracts below the flowers.

The flowers are a clear amethyst-lavender color that never fails to attract the attention of butterflies and native bees.

So far, after 16 years of cultivation in south Florida, it has weathered droughts, intense heat and humidity, tropical storms, and hurricanes. And it has done so without ever having been afflicted by a single pest—not even aphids. What is puzzling is that it is a species of the eastern and central United States from where it extends west to Montana, Wyoming, Colorado, and New Mexico. The closest that its natural range gets to Florida is North Carolina with reports from Alabama and Mississippi. Yet, it thrives in subtropical south Florida. I have tried growing other cultivars as well as wild forms of Symphyotrichum oblongifolium but all languish and die out after a year or two. But 'Raydon's Favorite' lives on to flower every year and no doubt becomes the favorite of every gardener who makes room for it in his or her yard.

Its cultivation is essentially effortless so long as it is provided with well drained soil and plenty of sunshine, although it appreciates a little water during extended droughts. It spreads vigorously and rapidly from underground suckers and propagation is easily effected by digging up and potting up the young suckers in the spring. Viable seed has never been set in my garden and, like many ecologically conservative perennial members of the daisy family, aromatic aster appears to be self-sterile.

Images and text © 2012 Rufino Osorio

Royal Palm – Roystonea regia

This is a quick post of three images of a cultivated royal palm, Roystonea regia, used as a landscape plant on the grounds of my work place. One image shows the abundant fruits, which are a favorite of starlings, a non-native invasive bird that has become the most abundant bird in North America. The other images are close-ups of the trunk.

Image and text © 2012 Rufino Osorio

Platanthera leucophaea — Prairie White-Fringed Orchid

Stephen Packard, prairie plant expert extraordinaire, has written a blog post on the discovery of the prairie white-fringed orchid (Platanthera leucophaea) within the boundaries of the City of Chicago. I played a role in that discovery although, at the time, I did not realize the full importance of finding this charismatic prairie plant in one of the most highly developed and urbanized regions of the country. Only when I learned that it was a federally-listed threatened species, and an Illinois-listed endangered species, did I realize how unusual it was to find this plant at the western outskirts of Chicago, not far from O'Hare Airport.

For the full story of Steve's efforts at protecting, preserving, and increasing the population of this showy terrestrial orchid, head on over to Steve's blog, Vestal Grove.

© 2012 Rufino Osorio

Hibiscus poeppigii – Fairy Hibiscus

Hibiscus poeppigii is a dwarf, shrubby perennial that bears small 1-inch long brilliant red flowers pollinated by bees and hummingbirds. It will produce flowers all year round so long as warm temperatures and adequate soil moisture prevails. Plants in full sun grow 1–4 feet (0.3–0.9 meters) tall and about half as wide and bear leaves 1–2 inches (2.5–5 centimeters) long. The stems will grow taller and the leaves larger if plants are situated in the shade or are overtopped by taller plants.

Hibiscus poeppigii is readily propagated from seed which germinate in about 10 days if sown during warm weather. It makes a delightful pot plant and I have grown it from seed to flowering in about 4 months in an 8-ounce (0.24 liter) plastic cup. In the ground, plants will rarely exceed 1.5 feet (0.46 meters) tall and be rather twiggy and sparsely leafy if grown in a dry, sunny spot. Of course, plants will grow much taller and be more lush if grown in continually moist soil or in part shade. Since it is the smallest of all Florida native hibiscus, and because it begins to flower when scarcely 6-inches (15.24 centimeters) tall, it is referred to as fairy hibiscus, a name which I much prefer over the prosaic and literal common name of Poeppig's hibiscus.

Hibiscus poeppigii is a state-listed endangered plant in Florida, where it occurs only in Miami-Dade County and the Monroe County keys. It also occurs as a native plant in the Caribbean (Cuba and Jamaica) as well as in Mexico (from Tamaulipas to Yucatán and Chiapas) and Guatemala. Taxonomically, it belongs to section Bombicella of the genus Hibiscus. In the New World, the section is centered in Mexico and Hibiscus poeppigii is the only representative of section Bombicella that is native east of the Mississippi River.

Reference:

Fryxell, Paul A. 1980. A Revision of the American Species of Hibiscus Section Bombicella (Malvaceae). Science and Education Administration, United States Department of Agriculture Technical Bulletin No. 1624. Internet

Image and text © 2012 Rufino Osorio

Hibiscus furcellatus – Sleepy Hibiscus

Hibiscus furcellatus is a large, coarse, shrubby perennial or shrub that bears ornamental, large, dark pink flowers pollinated by hummingbirds and bees. It is remarkable for its wide natural range and occurs from Florida, in the southeastern United States, all the way south to Paraguay and Argentina. It also occurs in the Greater Antilles and, by way of long distance dispersal from Central or South America, it is also native to Hawaii.

In Florida, the petals rarely spread very widely, thus accounting for the common name sleepy hibiscus since the flowers never fully "wake up." Occasionally, the petals will fully spread open but usually only for a short time and then only very early in the morning. Hibiscus furcellatus is easily cultivated from seeds and readily flowers during its first year. Its cultivation is undemanding and it grows equally well in moist or dry soils in light shade to full sun. Although wild plants are clearly perennial shrubs, plants cultivated in my garden have always behaved as annuals and must be grown from seed each year.

Image and text © 2012 Rufino Osorio

Hibiscus dasycalyx – Neches River Hibiscus

Hibiscus dasycalyx, the Neches River hibiscus, is an endangered hibiscus that naturally occurs in the floodplains of the Angelina, Neches, and Trinity rivers in eastern Texas. There are only about 500–600 plants in the wild and wild populations are threatened by habitat destruction and genetic contamination with the closely related Hibiscus laevis. It is sparingly cultivated and is easily grown from seeds or cuttings in continually moist soil in very light shade or full sun. Its cultivation in South Florida is complicated due to the plant being severely attacked by the Sri Lanka weevil (Myllocerus undatus). The adult weevils cause extensive feeding damage to the leaves and the subterranean larvae feed on the roots.

Image and text © 2012 Rufino Osorio