Sunday, July 25, 2010

Common Ironweed - Vernonia angustifolia

Common ironweed (Vernonia angustifolia) is a similar version of giant ironweed (V. gigantea) with narrower leaves and shares many of the same characteristics and uses.  It is found throughout the northern two-thirds of Florida, but is confined to the Southeast Coastal Plain in the U.S.  As such, it is a true southern ironweed.
Although sometimes also referred to as "tall ironweed", its Latin name draws reference to its relatively narrow leaves.  I believe this is a far better distinguishing characteristic between it and its "giant" cousin as common ironweed is nearly as tall in most settings as giant ironweed.
Common ironweed is deciduous and emerges in early spring; forming a basal rosette of elliptical leaves with serrated edges.  The linear flower stalk is evident by late spring and mature by summer.  The leaves along the stalk are quite narrow.  At maturity, the stalks are 2-3 feet tall.
The flowers of common ironweed are similar in color and size to giant ironweed, but the corymb is often a bit smaller in diameter.  The flowers are a stunning lavender in color and quite attractive to butterflies and other pollinators.
Common ironweed is most commonly found in moist flatwoods where it receives ample sunshine and above average moisture.  I have not found this species to be especially drought tolerant in my own landscape, though well-established specimens will "hang on" for some time during droughty periods.  Extended and/or repeated drought, however, is difficult on them and eventually kills them if supplemental water is not provided.
Use this species in a mixed wildflower garden and combine it in the middle portion of the landscape with other medium-tall species such as grassleaved golden aster (Pityopsis graminifolia), Garber's blazing star (Liatris garberi), red salvia (Salvia coccinea), Florida tickseed (Coreopsis leavenworthii) and skullcap (Scuttellaria integrifolia) that also tolerate slightly moist (not wet) conditions. 
For all its beauty and usefulness, common ironweed is only rarely offered for sale by commercial nurseries in Florida.  We intend to propagate it at Hawthorn Hill from seed we have collected this summer and hope to have specimens for sale by late spring 2011.  Inquire if you are interested and we will set some aside for you - assuming we have good germination. 

Giant Ironweed - Vernonia gigantea

As its common name implies, giant ironweed (Vernonia gigantea) is the tallest and most robust member of this genus.  It is found throughout the northern two-thirds of the state and in much of the eastern half of the nation - to southern Canada.  It is an adaptable plant and occurs in a wide variety of habitats.  Often, it is found in light gaps and the edges of wooded habitats, but it is equally abundant in sunnier locations as long as soil moisture is adequate.
Giant ironweed is deciduous and dies back to the ground each winter.  The cluster of tough basal leaves emerges in the early spring.  These are oval shaped, rather coarse and decidedly toothed along the margins.  By late spring, the central stalk begins to elongate and by late June to early July, the broad and rounded clusters of flowerheads are fully formed.  Each plant may stand 4-5 feet tall, depending on growing conditions.
Flowering occurs in July and can extend into August.  Deep rich-lavender aster flowers form small clusters across the crown of each plant.  These last for weeks and attract a wide assortment of butterflies and other pollinators - making this an excellent choice for a butterfly garden.
Giant ironweed can sucker extensively in the garden and will eventually move around to the places that best suit its growing requirements.  For this reason, some weeding is often necessary to confine it to the parts of the garden it is welcome.  Because of its size and height, it is best used in the back of the mixed wildflower garden.  Plant it in small clusters of 3 or 5, spaced about 18 inches part and the plants will spread and form a solid cluster in relatively short time.  These can be breathtaking in the right setting.
I have "lost" this species during periods of extended drought if I haven't watered sufficiently.  Although it is tolerant of a variety of conditions, it will not prosper in settings that remain too droughty.  If you have a moist location, use it in full sun and the butterflies will be attracted even more.
Giant ironweed is thankfully grown by a number of commercial sources, including members of AFFN - the Association of Florida Native Nurseries.  We have kept it in our landscape at Hawthorn Hill for years and greatly admire its beauty, but we have no intention of propagating it ourselves for sale at our nursery.

Sunday, July 11, 2010

Scrub Blue-eyed Grass - Sisyrinchium xerophyllum

Although common blue-eyed grass (Sisyrinchium angustifolium) is widely grown and propagated throughout Florida, its close relative - scrub blue-eyed grass (S. xerophyllum) is not and it is poorly known among home gardeners.  As its common and Latin names suggest, scrub blue-eyed grass is native to well-drained sandy uplands.  It requires these conditions and plenty of sunlight or it will not persist in the landscape.  Scrub blue-eyed grass is found throughout most of Florida, but it is nearly endemic; being found only sporadically outside of Florida in southern Georgia.
Scrub blue-eyed grass is a much more robust plant vegetatively than its common cousin.  Its leaves are nearly identical in shape, but they stand about 12 inches tall.  These are evergreen and the plants are perennial.
Flowering can occur sparingly in the spring, but is most common during the late summer.  The multiple flower stalks may stand nearly 2 feet tall.  The flowers are similar to its common cousin, but they tend to be a bit paler blue in color.  I have not seen other color forms in the wild.
Despite its attractiveness and ability to prosper in droughty soils, I am not aware of any commercial Florida nursery currently propagating scrub blue-eyed grass.  This is very regrettable and hopefully will change in the future.  We have grown this wonderful species for several years now in our nursery and hope to eventually divide our plants and make it available to interested gardeners.
Use scrub blue-eyed grass in well-drained sandy and sunny locations.  Plant it near the front half of the bed and use 5 or more plants together, spaced at least 8 inches part.  Mix it with other small to medium-small wildflowers of similar habitat needs, such as grass-leaved goldenaster, pink beardtongue, and wild petunia, but do not crowd individual plants.  Like most scrub species, their long-term health requires a bit of space between neighbors.
Hawthorn Hill does not currently have plants for sale, but we should in the near future. If you might be interested, let us know and we'll save you a few.

Blue-eyed Grass - Sisyrinchium angustifolium

Blue-eyed grass (Sisyrinchium angustifolium) is a member of the iris family and common to open moist habitats throughout Florida.  This is a perennial evergreen species which blooms profusely in the spring and then spends the rest of the year as a clump of thin grass-like leaves.  At this stage, it is sometimes difficult to detect.
Like other irises, blue-eyed grass slowly spreads outwards by forming "pups" off of the main leaf cluster.  These can be easily divided and planted elsewhere if you desire to move this plant to other locations in your landscape, or allowed to slowly spread outward to form largers clusters.  If left alone, individual plants eventually become at least 1 foot wide, but never taller than about 6 inches. 
Blooming occurs on stiff flower stalks which may stand a foot or so above the leaf mass.  The flowers are often bright blue with a yellow center, but many color forms are available from nurseries that range from deep purple to rose pink.  Individual flowers are open for only about a day, but flowers open successively on each stalk for several weeks and each stalk can have multiple flowers open at any one time.  Well-developed plants can have many flower stalks and a mass of blue-eyed grass can be quite attractive.
Although it prefers moist soils, blue-eyed grass can be grown in most typical landscape settings - if additional water is provided during periods of extended drought.  Use this plant along walkways and the edges of planting beds and plant it in mass.  Individual plants should be spaced about 6-8 inches apart and then allowed to grow into each other to form a single mass.  Eventually, masses benefit from being divided.  Use a sharp-edged spade and move them to a moist location so they can be easily established or into pots until their root masses re-develop. 
Because of its versatility, beauty and good behavior, blue-eyed grass is widely propagated and sold commercially.  We have several color forms in our landscape and always welcome its colorful display each spring.