Wednesday, October 27, 2010

Small's Jointweed - Polygonella myriophylla

Many of Florida's native buckwheats are best adapted to our driest, most well-drained soils. Small's jointweed (Polygonella myriophylla) is definitely one of those.  This endemic buckwheat is extremely rare, found only in four counties within the Lake Wales Ridge in central Florida. It is a state and federally listed endangered species and found only in scrub that is relatively open and sunny.  It disappears quickly when neighboring trees and shrubs get too thick and recolonizes after a fire when these woody plants are set back.
Also known as "sandlace", Smalls' jointweed is an evergreen woody plant that grows prostrate to the ground; its lacey red-cedar-like foliage giving the plant great grace.  The tips of the stems root where they come into regular contact with the sand and this complex system of roots helps ensure that the plant withstands periods of excessive drought.
Flowering can occur in nearly any month, but is most abundant in late summer and fall.  Small heads of white flowers appear at the ends of the stems and remain open for several weeks.  The flowers attract a wide variety of pollinators.
Small's jointweed is relatively easy to maintain in the landscape if given plenty of sun and excellent drainage.  As a groundcover in a scrub garden, it is striking and works well with many herbaceous wildflowers if not grown in crowded conditions.  Regrettably, it is only rarely available and I know of no one currently propagating it for landscape use. So, at present, we can only admire it in those few public scrub areas protected from development. 

Friday, October 22, 2010

Wand goldenrod - Solidago stricta

Wand goldenrod (Solidago stricta) occurs throughout Florida and much of the Southeast Coastal Plain in open sites with well-drained soils.  This is a common goldenrod, but goes largely unnoticed in most months because of its size and lack of dense foliage.
Like other goldenrods, wand goldenrod is deciduous.  In the spring, it produces a small cluster of linear leaves and then sends its thin stem upwards; eventually reaching a mature height of 2-4 feet.  This stem appears to be largely leafless as the tiny thin leaves are rather closely appressed against the stem.  Blooming occurs in the fall; October-November.  Unlike most species, the heads are linear and held close to the stem.  This gives the plants an appearance similar to the blazing stars (Liatris spp.).  Individual flowers are bright canary yellow; a bit brighter to my eye than many other goldenrods.
Wand goldenrod is only infrequently available from commercial nurseries, but one of the very best goldenrods for the home landscape.  Because of its size and growth form, it fits well into a mixed wildflower bed and makes its presence known only during the fall while it is in bloom.  At that time, it looks great mixed with other fall-blooming wildflowers - especially blazing stars, grassleaf goldenaster (Pityopsis graminifolia), and red salvia (Salvia coccinea).  Wand goldenrod suckers, but these can be easily weeded when necessary.  It also spreads by seeding.  Plant it in clusters of at least 3-5 individuals in the middle of a mixed wildflower planting.  It is adaptable to most soils and tolerates a bit of extra moisture better than many.

Chapman's goldenrod - Solidago odora var. chapmanii

Chapman's goldenrod (Solidago odora) occurs in two distinct forms in Florida.  Variety odora occurs throughout north Florida and south to Hernando County.  Its foliage produces a distinct fragrance somewhat like anise.  Variety chapmanii occurs throughout the peninsula and into the central panhandle.  Their ranges obviously overlap and telling them apart is difficult.  Besides the slight differences in foliage fragrance, they differ slightly in foliage shape and in the pattern of pubescence on the leaves and stems. The variety pictured above is chapmanii as the leaves are less linear.
Regardless of variety, this species is one of the best goldenrods for home landscaping.  It is extremely adaptable to most landscape settings (except soils that are too wet) and is better behaved than most other species.  Chapman's goldenrod is deciduous.  By early summer, it reaches its mature height of about 3 feet and begins blooming.  Blooming can occur over a wide variety of months, but is most common to the summer months.  In our garden, it is finished before the fall goldenrods begin.  Flowering occurs on the tips of each stem and the heads are arranged in very open loose panicles. 
This species suckers, but not aggressively.  Individual plants eventually work their way into most corners of the planting bed, but they tend to occur as scattered individual stems; not as dense colonies.  It also spreads well by seed.
Chapman's goldenrod works extremely well in mixed wildflower plantings, combined with species such as grassleaf goldenaster (Pityopsis graminifolia), blazing stars (Liatris spp.), Florida paintbrush (Carphephorus corymbosus), and similar medium-sized species common to open well-drained sites.  Because it tends to move about the garden, plant it individually or as small clusters in the middle portion of the bed and be prepared to weed out plants that find their way to the front.  Chapman's goldenrod and its other variety, Sweet goldenrod, are generally available commercially and should not be difficult to find. If you wish to add a goldenrod to your wildflower garden, this is a good choice.

Pinebarren goldenrod - Solidago fistulosa

Another one of Florida's common and large goldenrods is pinebarren goldenrod (Solidago fistulosa).  This species occurs throughout Florida and the Southeast in a wide variety of upland habitats, but is especially common to disturbed open fields and open pinelands.
This is a deciduous species that appears each spring and grows vigorously  upward through the summer; eventually reaching a mature height of 6-8 feet.  The leaves are oval and slightly pointed and remain about the same size all the way up the stem. 
Flowering occurs in fall; October- November.  The heads are open panicles and each flower is typical of the genus; small and bright yellow. 
Pinebarren goldenrod is a robust species that spreads rapidly in the landscape by suckering.  Eventually, it forms dense thickets that essentially exclude most other species unless planted with equally dominant wildflowers, grasses, or woody plants.  As such, it is a poor choice for small landscapes or planting areas where a large diversity of species are destired.  Use it as a screen in larger settings or as an accent planting where its spread can be easily confined.  In the latter settings, its robust growth and profuse flowering can be quite effective.
Pinebarren goldenrod is extremely adaptable, but only rarely offered commercially. 

Seaside goldenrod - Solidago sempervirens

Seaside goldenrod (Solidago stricta) is one of 20 goldenrods native to Florida and extremely common along our coastal dunes and the edges of salt marshes in counties throughout Florida.  It is not confined, however, to coastal habitats and can be found also in a number of interior counties in upland sites with well-drained soils. 
As its Latin name suggests, it is evergreen, but most of its above-ground stems do, in fact, die back in winter; leaving only a cluster of long, elliptical basal leaves.  Seaside goldenrod grows rapidly in the spring and summer months and produces a main stalk that reaches 8-9 feet in length.  As such, it is the tallest of our native species and a dominant component of whatever landscape it occurs in.  The pointed leaves go all the way to the top of the stem, but are greatly reduced in size from those at the base of the stem.
Flowering occurs in fall; October- November.  The flower heads are loose open panicles and, like most members of this genus, the individual flowers are small and bright yellow.  Migrating monarchs pay special attention to these blooms as they move down the coastline in late fall, but a wealth of other pollinators use them also.
Seaside goldenrod is widely available from commercial sources and is frequently planted in home landscapes.  This is a good choice for large open areas, for coastal plantings, or as a screen to block out neighboring landscapes, but it is not the best goldenrod for smaller planting beds as it is just too overwhelming.  Unlike most members of this genus, seaside goldenrod does not produce suckers, but it does spread by forming offshoots from its main base.  Over time, it forms large masses.  Plant it no closer than 12 inches apart and keep it from spreading by judicious weeding in the late winter or early spring.  It mixes well with large coastal grasses, such as seaoats, but not with most other wildflowers. This is an extremely adaptable species that can be used in nearly any setting except deep shade. 

Thursday, October 21, 2010

Georgia aster - Symphyotrichum georgianum

Georgia aster (Symphyotrichum georgianum) occurs in only one Florida county along the Georgia border and is a state threatened species in Georgia as well.  It is resident to well-drained soils; the edges and openings within deciduous upland forests and in cleared areas such as roadway right-of-ways. 
Like other members of this genus (formerly placed in the genus, Aster), it is a deciduous perennial that dies back to the ground each winter and re-emerges again in the spring.  Its upward growth is rapid and by early fall it stands 4-5 feet tall.  The semi-woody stem is stout and both the stems and leaves are rough hairy.  Many side branches are present and blooming occurs on the ends of each in fall; October into November. 
Georgia aster is not a particularly beautiful foliage plant.  Its large, almost gangly growth form and its rough elliptical leaves are not especially interesting.  It makes up for that, however, by its brilliant blue flowers.  The ray petals are a rich purple-blue that is matched by no other wildflower; a bit like eastern silver aster, but richer.  The disc flowers are white and turn reddish as they age.  Each flower head is more than 1 inch across and large numbers are produced at any one time.  Aster flowers are of great interest to butterflies and bees, and this species is no exception.
We have not yet tried this species in our Pinellas County landscape, but suspect it will perform much the same as other dry-site asters that we currently grow.  Georgia aster suckers as other asters tend to do and eventually produces colonies consisting of many stems.  Because of its size, it would have to be planted at the back of a mixed wildflower garden and used partly as a screen.  Currently, we have 3 blooming plants in pots at our Hawthorn Hill nursery and we intend to collect seed from them later this winter to experiment more with them.  If you are interested in seedlings (and we get some...), please let us know.