Sunday, September 25, 2011

Solidago tortifolia - Twistedleaf goldenrod

Twistedleaf goldenrod (Solidago tortifolia) is yet another large and often dominating species within this genus. It is a common species in open fields and woodlands across most of Florida and in much of the Southeast from Texas to Virginia. 
This species is deciduous, but grows rapidly through the summer to reach a mature height of 6-8 feet by fall.  In Pinellas County, it blooms in mid-September into October, just a bit ahead of the peak bloom time for pinebarren goldenrod (S. fistulosa), another large goldenrod sometimes confused with this species.
Unique to this goldenrod is its twisted leaves.  Each is willowlike and most have a half twist that is quite distinctive. The leaves going up the stem also remain nearly the same size as the lower leaves.
The flowers occur on arching stems near the tip of the plants.  These are arranged in open panicles like many other species, but they are not as uniformly arranged as in pinebarren goldenrod and the side stems often fall away from the main stem and are nearly horizontal to the ground surface below.  This makes the overall infloresences irregular and a bit more open than most.
Twistedleaf goldenrod is somewhat "weedy" in nature and is a difficult species to maintain in small landscapes.  It suckers extensively and becomes quite dominant when planted with other species.  In expansive settings, however, it can be striking with its large yellow inflorescences and its interesting foliage.  It is only very infrequently offered by native plant nurseries in Florida  and may be difficult to locate.  We have grown it at Hawthorn Hill, but do not plan to offer it commercially. 

Saturday, September 24, 2011

Solidago fistulosa - Pinebarren goldenrod

Pinebarren goldenrod (Solidago fistulosa) is another exceptionally widespread Florida species; found statewide in a variety of upland habitats.  It is a species primarily of the Southeast Coastal Plain, however, and follows the curve of North America from Louisiana to New Jersey. 
As its common name suggests, pinebarren goldenrod is a common component of pine flatwoods and open pine forests.  I find it most commonly in mesic conditions; not areas that are the most well-drained.  It is deciduous. Growth occurs in very early spring and individual stems eventually reach a mature height of 4-6 feet (rarely a bit taller) by its fall blooming season.  Like seaside goldenrod (S. sempervirens), the leaves are lance-shaped and remain fairly large going up the stem.  These leaves, however, are slightly toothed and the stems are slightly "hairy."  It also differs in that it produces large numbers of rhizomes and suckers quite aggressively in all directions.  For this reason, pinebarren goldenrod often occurs in dense patches; almost as monocultures, when it is in an area that provides ideal growing conditions.
Pinebarren goldenrod produces large open panicles of bright yellow flowers in fall.  In my region of the state, it normally starts blooming in October and continues into November.  These panicles are rather "regular", not overly arching and definitely not lop-sided off the main stem. 
This is an extremely attractive species that is quite easy to grow, but consideration must be given to its aggressive nature.  It performs best in expansive landscapes where its dense stems can serve to screen adjacent views or structures.  It is a very poor choice for small landscaped areas or in situations where a wide diversity of wildflowers is desired.
Pinebarren goldenrod is frequently propagated by members of FANN - the Florida Association of Native Nurseries, and can usually be located for home landscapes. 

Solidago sempervirens - Seaside goldenrod

Seaside goldenrod (Solidago sempervirens) is perhaps the most distinctive species among Florida's goldenrods.  Found throughout much of Florida, but primarily within our coastal counties, this species is both robust and evergreen.  Though its common name suggests it to be "seaside", it also is resident to most states and provinces in the eastern half of North America.
As its Latin name indicates, seaside goldenrod is not entirely deciduous like other Florida species.  Over winter, it maintains its large strap-like leaves.  Then, in early spring, it begins its upward growth.  This occurs throughout the summer and early fall.  By its late fall blooming season, seaside goldenrod may stand 8 feet tall. 
The foliage also stays rather robust up the stem to the flower head.  The leaves are thick and elliptical, with few teeth along the margin.  Like all goldenrods, it forms multi-stemmed colonies over time, but it does not produce underground rhizomes that would allow it to aggressively sucker as some.  It also spreads easily from seed and new plants are likely to arise almost anywhere from plants not deadheaded and allowed to shed their cottony seed.
Seaside goldenrod blooms most abundantly in late fall.  The flower heads are held somewhat upright as spires; not at all angles like some that also arch over.  These bright golden heads of flowers attract a wide assortment of pollinators - as all goldenrods do. Its just that their sheer numbers make this species especially good for migrating monarch butterflies and a great many bees.
Seaside goldenrod is widely propagated for home landscapes and restoration projects by nurseries affiliated with FANN - the Florida Association of Native Nurseries.  It makes a stunning landscape addition, but I believe it looks best when planted in mass and in expansive settings.  Its very large size and tendency to spread make it a poor choice in small areas or areas not confined well by concrete.

Thursday, September 8, 2011

Goldenrods - Solidago spp.

There is no better harbinger of fall than goldenrods (Solidago spp.). Their bright yellow blooms can be spectacular and their generally robust nature makes them stand out wherever they occur.  These blooms are excellent nectar sources for pollinating insects.  No garden should be without at least some goldenrods for the bees and butterflies.
Florida has 19 unique species (plus two distinct varieties of one species, Solidago odora), and one species or another can be found in pretty much every habitat type throughout the state.  The problem with this diversity is that the individual species are often difficult for the average person to identify.  Most all of us are simply content to know its a goldenrod and leave it at that.  But, eventually the underlying urge to accurately name it rears its ugly head.
In the next series of posts (and over the next couple of weeks), I will attempt making them a bit easier.  Identifying individual species requires you to look at the whole picture.  It is not enough to simply look at part of it.  Often it's a combination of key characteristices that will enable you to know for certain which species you are looking at.  The most important things to notice are:
1. Habitat - Where is it growing?  Different species tend to be most often encountered in distinct habitat types. Knowing which species are most likely to be encountered where will often limit the number of species you have to sort out.
2. Blooming Season - Though most species bloom in the "fall", even that is protracted over several months.  Some goldenrods, like S. odora, are most likely to flower in the summer and some fall blooming species are most likely to bloom in early fall while others flower most commonly very late in the season. If you watch goldenrods, you may notice that there is a progression of bloom times among them.
3. Leaf Shape - Though there is always some variation within species, most goldenrods have fairly distinctive foliage.  I will try to post good photos of each of the species I have good photos of.  What is difficult to show well is the relative size of the leaves to each other.
4. Shape of the Flower Head - While many goldenrods have a loose panicle of blooms that fall away from the main stem in all directions, many others are very distinctive.  Even the "loose panicle" types are different and could be told from each other if the species were side by side...  Of course, that doesn't happen much in nature, but after some practice you will get an eye for telling them apart this way.
5. Degree of  Suckering - All goldenrods sucker.  Their root systems send rhizomes out from the main plant and these produce more stems, but not every species suckers aggressively.  Some, like the pinebarren goldenrod (S. fistulosa) (photo below shows extensive suckers of this species), produce so many suckers that they soon develop an almost monoculture of stems in well-defined patches.  Others, like Chapman's goldenrod (S. odora var. chapmanii), send far fewer suckers out and individuals are often fairly widely spaced in the landscape.
6. Relative Height - Some goldenrods, like seaside goldenrod (S. sempervirens) are giants and can reach heights well over 6 feet, while others, like wand goldenrod (S. stricta) are diminutive in comparison; standing only about 2-3 feet with their flower stalk.  Knowing the extremes and which ones fall in the middle can often help narrow the field down when trying to make an identification.

Very few of our many goldenrods are widely propagated for the home landscape, but there is some evidence that this is changing as the public comes to understand the genus a bit better and looks for some of the better species for landscape settings.  So - stayed tuned for my future posts on the individual speces - and start to look for them as our summer turns to fall and winter.