Friday, December 30, 2011

Frostweed/Winged Stem - Verbesina virginica

Frostweed or winged stem (Verbesina virginica) is common statewide, occurring most often at the edge of hammocks where it receives part sun and average to moist soil, though it is remarkably tolerant of a wide variety of conditions.  It also occurs throughout much of the eastern half of the U.S. - west to Texas and north to Iowa and then east to Pennsylvania. Throughout this range, it is rather common.
The common names for this plant are self-evident; "frostweed" because it blooms so late in the fall and "winged stem", because of the wing-like appendages on the stem seen in the bottom photo above. This is a coarse, robust herbaceous species that dies to the ground each winter (some basal leaves may remain depending on latitude) and emerges quickly each spring.  Though not woody, it eventually reaches heights of 6-8 feet by October.  The tough scabrous leaves are toothed along the margins and can be nearly 12 inches long - especially near the base.  At its mature height, this is a somewhat weedy looking wildflower and large enough to overwhelm smaller species around it.
Despite this nature, there are good reasons to admire frostweed when it is in bloom.  In October and November, individual plants produce large numbers of white flowers with porcelain white ray petals.  At this time, they are a bevy of activity, attracting pollinators of all types.  The first time I encountered this plant, at Highlands Hammock State Park in Highlands County, I must have counted at least 50 tiger swallowtails nectaring on a patch that lined an old citrus grove.  There were other pollinators too, but the swallowtails captured my attention and I pretty much ignored everything else around me.
Frostweed is sold by a number of commercial nurseries affiliated with FANN - the Florida Association of Native Nurseries, but it should be added to a home landscape with forethought.  For one, it is tall and dominating.  Use it at the back of a mixed wildflower area or as a screen, but if used to screen a view, realize that it is deciduous and absent during the winter months.  Second, it spreads quickly once established and will require annual thorough weeding to keep it only where you want it.  But, if you take this all into account, it can be a very valuable addition to a pollinator garden.
Frostweed thrives in a very wide variety of conditions.  It may perform best if planted in partial sun or locations where it gets sun for half days, but it will flower if given more or less sun than that.  It prefers moist soil, but is amazingly tough in droughty soils as well.  Just don't plant it in submerged locations or in full sun on top of a sand dune.

Thursday, December 29, 2011

Salt and Pepper - Melanthera nivea

Salt and pepper (Melanthera nivea), also known as "snow squarestem", is a robust perennial wildflower found statewide in Florida and throughout much of the Southeast.  It is a Species of Concern in Kentucky and endangered in southern Illinois.  This plant often acts like a weed; it occurs in disturbed open habitats, is variable in growth form, and can tolerate a very wide range of conditions. This makes it an easy wildflower to add to nearly any landscape setting, but with caution... as it will require some pruning and control over time.
Although natural short forms are sometimes encountered, salt and pepper most frequently is seen as a tall and lanky semi-woody specimen that reaches a mature height of 3-4 feet.  Like dotted horsemint (Monarda punctata), it is deciduous in winter or retains some of its basal leaves, and then quickly grows upright beginning in early spring.  This is in the Aster family, though its stems are square like those of the mints.  The diamond-shaped leaves are tough and coarse, and often opposite on the stem. 
Flowering occurs in late summer and may last well into early winter.  The plants photographed above still had a few flower heads in late December. It's the flowers that give it its common name.  There are no ray petals and the central disk is composed of small white tubular blooms. Arising from inside each are black anthers (the male portion of the flower).  This is what gives it its Latin genus name.
These flower heads are especially attractive to pollinating insects.  Bees, butterflies, and a host of others are drawn to these blooms and they are a focal point of activity in the garden. Each flower ultimately produces a number of achenes (seeds) and they are released as the heads dry.
Salt and pepper can make a valuable and interesting addition to a wildflower garden if it is maintained.  I would recommend periodic pruning to keep plants no taller than 3 feet and so they remain fuller.  I would also recommend deadheading them once the blooms are spent to reduce the number of seedlings that will come up the following year.
Salt and pepper is only occasionally offered by nurseries affiliated with FANN - the Florida Association of Native Nurseries so it may take some looking to find it if you wish to add it to your landscape.  We do not propagate it at Hawthorn Hill.

Tuesday, December 27, 2011

Rose of Plymouth - Sabatia stellaris

Rose of Plymouth (Sabatia stellaris) is one of Florida's most widely distributed marsh pinks; found statewide from the western panhandle to the Keys.  It is a species of the Southeastern Coastal Plain and is distributed from Louisiana to Florida and north up the Eastern Seaboard to New York and Massachusetts.  It is quite rare, however, in the northern portion of its range; it is listed as state endangered in Connecticut and Massachusetts and threatened in New York and Rhode Island.
Rose of Plymouth is sometimes called "sea pink", and it is both tolerant of salt and flooded soils.  Although it is considered an "obligate" wetland plant by the National Wetland Inventory, I have found it often in seasonally wet pine flatwoods where soils are often dry for months at a time. 
Sabatias/marsh pinks are annuals and require open soil to reseed and spread over time.  Depending on the latitude in Florida, seedlings quickly emerge in early spring and reach their mature height by summer.  The plants above, that I photographed in a mesic pine flatwoods in Lee County, were only about 6 inches tall, but they often reach heights of about 12 inches.  The foliage is much reduced and the plant consists mostly of thin stems that overlap each other and form an almost rounded mass.  Flowering occurs at the ends of the stems and lasts for many weeks.
Like most in this genus, rose of plymouth produces a great many soft-pink blooms.  The centers are vivid yellow and form a star-shaped pattern around the green ovary.  There are five petals.
Marsh pinks, because they are annuals perhaps, are not often grown commercially by any of the commercial nurseries affiliated with FANN - the Florida Association of Native Nurseries.  We also do not propagate these species at Hawthorn Hill.  To grow this in a landscape would require providing it with ample moisture, especially in the summer season, and ample light.  To persist, it would also require open soil to reseed into.  But, perhaps this is a species and a genus that is simply best admired in those wild places where it occurs.

Saturday, December 24, 2011

Pinebarren Rockrose - Crocanthemum corymbosum

Pinebarren rockrose (Crocanthemum corymbosum) is found statewide in open well-drained habitats, including scrub and sandhill.  This is a plant of the Southeast Coastal Plain and also occurs from Mississippi to North Carolina. 
Like other species in this small genus, pinebarren rockrose is a perennial sub-shrub.  Its thin wiry stems rarely stand taller than 12 inches and the plants are tardily deciduous in late winter.  Over time, this species slowly suckers and produces a mounded colony that can be several feet across.
The foliage is sparse; often clustered near the ends of the stems. Each leaf is elliptical, bluish green and with deep-set veins.  The edges of each leaf tend to roll under along the leaf margin as well.
Flowering can occur for several months; from late spring to early summer.  This is when this plant truly "shines".  Large numbers of bright yellow blossoms adorn the top of each stem. They have five petals and, in sharp contrast to each, are bright orange anthers.  Each bloom last only a day, but the buds are arranged in clusters and they open in succession.
The rockroses make excellent additions to the front of a mixed wildflower garden, but they are rarely offered.  We have been growing pinebarren rockrose for several years at Hawthorn Hill, but generally have it only in small numbers.
This is an easy wildflower to maintain.  Give it plenty of sun and good drainage.  It is forgiving if not exposed to too much water or shade.  Give it some room too, as it will want to spread out and it will be more striking if it isn't competing for space.  Because of its low stature, it should be grown with other small wildflowers such as twinflower, wild petunia, pink penstemon, and the like.

Thursday, December 22, 2011

Wild Petunia - Ruellia caroliniensis

Wild petunia (Ruellia caroliniensis) is a very common wildflower in Florida; found statewide in a variety of habitat types.  It is also distributed throughout the eastern half of North America, though it becomes much more rare in states such as Pennsylvania and New Jersey.  Wild petunia extends its range in the south as far west as Texas.
Though its flowers closely resemble those of the common garden petunia in shape, they are not related.  True petunias are members of the Solanaceae, the family that includes tomatoes, eggplants, potatoes, and nightshades.  Ruellias, the "wild petunias", are members of the Acanthaceae; a family that includes a great many tropical and semi-tropical plants commonly grown in Florida for their flowers - e.g. Justicia and Thunbergia.  The one characteristic that members of this family share is that their ripened seed capsules explode and send the seeds off a good distance away from the parent plant.  Because of this, all Ruellias tend to move around a landscape over time.
Wild petunia is one of the most adaptable and easy to grow wildflowers available to home gardeners in Florida.  Though it is most often encountered in sandy & sunny uplands, it will tolerate a great deal of shade and moisture as well.  I have found it in shady hammocks in nearly saturated soils and in pure sand in exposed scrub.  In the garden, it will grow nearly everywhere, though it will be leggier and bloom less often in shade.
Wild petunia is a long-lived perennial that dies back to the ground each winter.  Its leaves emerge in early spring and it quickly reaches its mature height of about 12-18 inches by late April - early May.  The leaves are ovate and opposite on the stem.  Often, many stems arise from the basal portion near the root mass and the plants develop a nice rounded form. 
Blooming occurs almost non-stop from late spring to late summer/early fall.  The trumpet-shaped flowers are about 1 inch across and vary in color from nearly white to a deep purple.  Often, they occur in pairs and they remain open for only one day.  I have found that butterflies relish the nectar from these flowers; in some of my gardens, they have been the top choice among nectar plants. 
Wild petunia scatters its seed everywhere in the landscape.  Once established, you will find new plants many feet from their parents, and after several years, you may find them in the front and the back yard - as well as everywhere in between.  Often, this is a good thing.  How many attractive wildflowers in your garden are this easy to propagate?  And, their small size does not make them crowd out larger neighbors.  But, it can be a nuisance to weed them if you are wanting a more formal look.
Wild petunia is one of the most widely propagated wildflowers in Florida and is grown by a great many nurseries affiliated with FANN - the Florida Association of Native Nurseries.  Be careful NOT to purchase the incredibly invasive Mexican wild petunia (R. simplex; syn. R. brittoniana; R. tweediana) pictured below, however.  They are very different plants and Mexican wild petunia...

has become extemely problematic to Florida's natural areas.  Mexican wild petunia spreads quickly from underground runners and is nearly impossible to eliminate without the use of herbicides.
Use our native wild petunia in mixed wildflower gardens.  Do not use it in large patches because it is absent in the winter and this will create bare patches of dirt that are unattractive.  Use smaller patches mixed with short grasses such as pinewoods dropseed (Sporobolus junceus) and wiregrass (Aristida spp.) and mix it with short wildflowers that maintain their basal leaves, such as pink penstemon (Penstemon australis).