Tuesday, November 28, 2017

Corkwood - Stillingia aquatica

Corkwood (Stillingia aquatica) is a semi-woody shrub found nearly statewide in Florida in shallow-water marshes and the edges of freshwater swamps.  It also is reported to occur in Georgia, Alabama and South Carolina. Unlike is close relative, Queen's delight (S. sylvatica), corkwood is an obligate wetland plant that is never found in habitats that are only seasonally wet. It also does not die back to the ground in the winter, though it loses its foliage.
Corkwood reaches a mature height of about 4 feet on thin woody stems. The bark is a dull rusty red in color. The foliage is mostly confined to the ends of the stems. This gives it a rather open aspect. The 6-12 inch-long leaves are narrow with a prominent mid-vein. The edges of the leaf margins have small, but conspicuous teeth and often are edged in red.
As a member of the Euphorbia family, the individual flowers are not especially showy.  For one, they lack petals completely. A few female flowers are clustered at the base of the 2-3 inch-long stalk while the numerous male flowers are spaced above. Flowering occurs over a protracted period from late spring to fall. The ripened seed capsules are three-parted and they "explode" when fully ripe - sending the seeds several feet away in random directions.
I have never seen corkwood offered for sale by any of the nurseries affiliated with FANN - the Florida Association of Native Nurseries, though I have sowed seed here at Hawthorn Hill for sale in Spring 2018. It is a very interesting addition to an aquatic planting, but definitely not a showy one. Use it in the shallow-water margins of lake and marsh plantings. I would plant this in small clusters for maximum effect and mix it with showier wildflowers such as native canna (Canna flaccida) and iris (Iris spp.). Bees are attracted to the small greenish flowers

Sunday, November 26, 2017

Yellow passionvine - Passiflora lutea

Yellow passionvine (Passiflora lutea) is native to the Florida panhandle and a very few counties in the upper peninsula. It also is found throughout the South and Midwest from Texas and Nebraska to Maryland and Pennsylvania on the East Coast. Throughout this extended range, it is most often encountered in the understory of deciduous woodlands in moist to mesic conditions.
In many respects, yellow passionvine occupies the same role (niche) as winged maypop (P. suberosa) does in the rest of Florida. It can go largely unnoticed in the landscape when butterflies are not fluttering about it. The leaves are three-lobed, but much wider than long and often with silvery markings along the leaf veins - best seen in the top photo. Flowering occurs in late spring and summer, and as the name suggests, the blooms are a pale yellow in color. Each flower is small and can go unnoticed. Deep-purple fruit follow about a month later.
Yellow passionvine is the preferred host plant for zebra heliconian butterflies in north Florida for much the same reasons as winged maypop fills this role further south. Gulf fritillary butterflies will use it also if the plant extends itself into a sunny location.
This passionvine is only rarely offered for sale by nurseries affiliated with the Florida Association of Native Nurseries (FANN), but it is sometimes offered by native nurseries to our immediate north. I have not had success with this species in my Pinellas County landscape and do not recommend it for locations outside its natural range.  If you decide to grow it, plant it in a rich woodland soil, in dappled light. Over time, it will spread by underground stems and by bird-planted fruit.

Winged maypop - Passiflora suberosa

Winged maypop (Passiflora suberosa) is found throughout peninsular Florida in a wide variety of habitats. Though not a showy wildflower (and therefore sometimes overlooked), its presence is often detected by the flurry of butterfly activity around it.  Winged maypop is equally at home in mostly sunny openings as well as mostly shaded woodlands and it is widely distributed by birds into all of these locations as they feed on its small purple fruit. 
Named for the corky "wings" along its mature stems (visible in the top photo), winged maypop works its way up and around nearby vegetation - extending a dozen or more feet away from its base. Like other passionvines, it has tendrils that aid its ability to climb securely. The small glossy leaves are variable in shape, but always three-lobed with a deep vein running the length of each.
Flowering occurs from late spring through fall. The tiny pale flowers are typical for the genus, but can go largely unnoticed because of their size. They are pollinated by bees and fertilized flowers form round deep-purple fruit that ripen about a month later. They are about 1/4-1/3 inch long. As mentioned above, they are widely fed on by songbirds and the seed are, therefore, widely scattered as well.
This wildflower would largely be considered an afterthought among wildflower gardeners if not for the fact that it is essential in a butterfly garden. Because it does well in dappled sun, this is the best host plant for the zebra heliconion (aka zebra longwing) in much of Florida. As zebras typically shun sunny areas to lay their eggs, most other passionvines are rarely used by them. The exception is yellow passionvine (P. lutea) which fills this role in the Florida panhandle counties. Winged maypop does well in sunny locations too, and in this setting it serves as a host for the caterpillars of Gulf fritillary and julia butterflies.
Winged maypop is likely to already be in your landscape - or to show up someday unannounced, but it is widely propagated by native plant nurseries if you wish to add it yourself.  I think it does best in average soil where it gets partial sun. If you can introduce it to a location where it can grow in both shady and sunny directions, it will maximize its value as a larval food plant.