Croton punctatus — Gulf Croton

A fully mature, densely branched plant about three years old. It is approximately 2.5 feet tall and about 3.5 feet wide.

Croton punctatus is an easily grown, but short-lived, shrub that reaches full maturity in 2–3 years and then begins a slow decline as it devotes itself to maximizing flowering and seed production. Its most distinctive feature is its leaves, which are densely coated with silvery scales resulting in leaves that vary in color from grayish green to silvery white. Young leaves have the densest coating of scales and can be so shiny and white as to appear to be made up of a metal such as aluminum. This is reflected in one of its common names, silverleaf croton.

A close-up of the leaves on a young, 6-month-old plant just beginning to flower.

Gulf croton naturally occurs in coastal strand and beach dunes along the Atlantic coasts of the Carolinas, Georgia, and Florida, from where it extends to the Gulf states and Cuba. It well lives up to its name, gulf croton, because it occurs along coasts nearly throughout the entirety of the Gulf of Mexico, from the western Florida coast to Texas and on to Mexico, Central America, and northern South America (Gann et al. 2016). In Florida, it has been recorded all along our coastline but it is apparently absent, or at least not recorded, from the Florida Keys, the coasts of mainland Monroe County, and Florida's west coast from Wakalla County to Pasco County (Wunderlin et al. 2016). Surprisingly, there are disjunct occurrences from the landlocked counties of Dauphin and Philadelphia in Pennsylvania (USDA 2016). All United States occurrences of gulf croton are in coastal counties except for the two Pennsylvania counties and Leon County in Florida and Brooks County in Georgia.

Its natural habitat provides clear clues to its cultivation and, as is the case with most beach-dwelling plants, it requires well-drained soil in a location where it receives full sun for most of the day. It is extremely drought tolerant once established but, for the healthiest, most densely branched, and beautiful plants, supplemental water should be provided during extreme or very long dry spells. In garden settings, it may be used as an accent plant or as a tallish groundcover. It is also useful as a small shrub in wildflower gardens or butterfly gardens where its fragrant flowers attract a wide variety of native flower-visiting insects. But gardeners must bear in mind that it is short-lived and it is rare for individual plants to last more than three or four years. Ample moisture produces big, beautiful plants but these tend to be the shortest lived, whereas plants grown under drier, leaner conditions tend to be the longest lived. However, declining plants are soon replaced by self-sown seedlings if the garden has open, sunny areas in which the seedlings can establish themselves. Propagation is by seeds or cuttings but seeds are difficult to gather because the capsules open ballistically and hurl the seeds far from the mother plant. I have never tried to grow gulf croton from cuttings because it abundantly self-seeds in my garden, but local native plant enthusiast, Ryan Leavengood, has had good success rooting cuttings of gulf croton in perlite and a rooted cutting from Ryan was the source of my original plant.

The flowers are not large or showy but they are reportedly fragrant and they attract a wide variety of insects. The flowers are either male or female but both genders are carried on the same plant.

Because it naturally grows in coastal strand and beach dunes, gulf croton is well adapted to the stressful environment of saltwater coasts and it is resistant to intense sunlight, strong winds, sand scouring, burial, high soil temperatures, low nutrient levels, and the occasional salt spray (Lonard & Judd 2009). As a consequence of its adaptation to life on sand dunes, it is valuable in coastal habitat restorations where it is an important element of the sand dune vegetation and helps to both form new sand dunes and reduce the erosion of established dunes.

Besides gulf croton and silverleaf croton, it is also known as beach-tea, which I assume is a reference to its previous use as a medicinal tea; however, I have not been able to locate any information on medicinal uses. Interestingly, Lonard & Judd (2009), who prepared a thorough review of Croton punctatus, were also unable to find any information on this plant's medicinal uses.

Note: Gulf croton is a true croton in the genus Croton, a large genus of about 750 species found nearly throughout the world but concentrated in the tropics and subtropics. The ornamental croton with variegated leaves that is a ubiquitous tropical landscape cliché, is in the same family but is a member of the genus Codiaeum.

A native bee visits the flowers of Croton punctatus. The flowers are attractive to a wide range of native pollinators.

References:

• Gann, G.D., M.E. Abdo, J.W. Gann, G.D. Gann, Sr., S.W. Woodmansee, K.A. Bradley, E. Grahl, and K.N. Hines. 2005–2016. Natives For Your Neighborhood: Croton punctatus. Institute for Regional Conservation. Link visited 8 June 2016.
• Lonard, R.I. and F.W. Judd. 2009. The biological flora of coastal dunes and wetlands: Croton punctatus Jacquin. Journal of Coastal Research 25(1): 23–29. doi: http://dx.doi.org/10.2112/07-0933.1
• USDA. 2007–2016. The PLANTS Database. Baton Rouge: United States Department of Agriculture National Plant Data Center. Link visited 8 June 2016.
• Wunderlin, R.P., B.F. Hansen, A.R. Franck, and F.B. Essig. 2016. Atlas of Florida Plants. Institute for Systematic Botany, University of South Florida, Tampa. Link visited 8 June 2016.

Image and text © 2016 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

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 aculeatus – Pineland Hibiscus

Hibiscus aculeatus is a perennial hibiscus native to the southeastern United States coastal plain in North Carolina, South Carolina, Georgia, Florida, Alabama, Mississippi, and Louisiana, as well as in Hardin County, Texas. In late winter or spring, it produces thick, somewhat woody, ascending to erect stems with alternate, deeply lobed, roughly hairy leaves. It begins to flower soon thereafter and can continue flowering so long as moist to wet conditions prevail. The flowers are comparatively large—note that they are larger than the leaves—and are very showy as a result of their pale yellow to creamy white color with a contrasting maroon-red eye. If pollinated by bees, butterflies, or hummingbirds, they are soon followed by rather large capsules that are covered with coarse, sharp hairs.

As is apparent from its common name, pineland hibiscus frequently occurs in wet pine flatwoods, but it is also found in bogs, savannas, and roadside ditches. Unlike many other southeastern United States hibiscus, it often occurs where there is no permanent standing water and perhaps this is the reason that it is the easiest of southeastern native hibiscus to grow under ordinary garden conditions in a perennial border. Hibiscus aculeatus is extremely drought tolerant and, under adverse conditions, will produce only one or two short stems; however, under ideal conditions, it will form a large, bushy mass with many stems up to 3 feet (0.9 meters) tall and about as wide or wider. Self-sown seedlings have been few and welcomed in my dryish garden but I would imagine that it would spread from seed far more aggressively if provided with continually moist soil in sunny, open areas free from taller competing plants. In autumn or early winter, the deceptively woody stems die back to the ground and, in formal garden situations, will need to be cut down, otherwise, it requires no other maintenance. It is not particularly bothered by pests except the occasional aphid or scale, but rarely to any serious extent. Due to its ease of cultivation and value in attracting bees, butterflies, and hummingbirds, it is a welcome addition to the garden and is recommended wherever one can provide a moist, sunny spot for this attractive and easily grown hibiscus.

In Florida, Hibiscus aculeatus occurs throughout the panhandle as well as much of northern Florida, from which it extends south to Lake County. In spite of its northern distribution, it is remarkably adaptable and my original plant, first placed in the ground in February 1996, is still with me, more than 16 years later, in my southern Florida garden. Another common name for Hibiscus aculeatus is comfort root, this being an allusion to the soothing, comforting qualities of its mucilage-containing roots.

Images and text © 2012 Rufino Osorio

Gaillardia pulchella – Firewheel

Gaillardia pulchella has several common names, including "indian blanket" and "firewheel."

Gaillardia pulchella is an easily grown annual commonly cultivated for its showy flowers. The flowers are exceptionally attractive to native bees as well as to a wide variety of both large and small butterflies. Although commonly regarded as native to Florida, the genus is centered in the great plains of the United States. Also, Florida plants exhibit wide variation in the size, form, and color of the ray florets (the so-called petals of a daisy), and this bolsters the possibility that perhaps some populations in Florida are derived from plants that escaped cultivation. This particularly showy form was photographed on a deeply overcast day at the Native Choice Nursery in Boynton Beach on Saturday, May 26, 2012.

Image and text © 2012 Rufino Osorio