Monday, April 29, 2013

Swamp Twinflower - Dyschoriste humistrata

Swamp twinflower (Dyschoriste humistrata) is a wetland relative of the nearly ubiquitous upland twinflower (D. oblongifolia). Unlike its close cousin, swamp twinflower is confined to the peninsula, from the Georgia border to DeSoto County in the south-central region.  Here, it occurs mostly in the partially shaded edges of forested wetlands.  This twinflower has also been reported in Georgia and South Carolina.
Swamp twinflower is a deciduous perennial. It emerges in early spring and produces a large number of weak decumbent stems.  Each reaches a length of several feet and and they root in various places as they touch moist soil. The deep green almost-succulent leaves are opposite each other on the stem, somewhat ovoid in shape, and about 1/2 inch long.  The foliage is attractive and the plant's habit makes it an interesting ground cover for somewhat shady and moist locations.
Flowering can occur in most months, but is most common from late spring to early summer.  The flowers are a pale lavender with a deeper lavender throat.  They are less showy than those of its more common cousin and smaller; typically half the length of D. oblongifolia.
Swamp twinflower has never been offered, to my knowledge, by anyone associated with FANN - the Florida Association of Native Nurseries, though it has potential as a flowering ground cover if planted in the right location.  Use it in partly sunny to mostly shady locations where the soil maintains some moisture.  I am told that it has good tolerance for occasional drought, but it won't persist if not kept frequently moist. We are currently experimenting with swamp twinflower at Hawthorn Hill.  As we learn more about its adaptability, we will keep you posted.

Sunday, April 7, 2013

Golden Alexander - Zizia aurea

Golden alexander (Zizia aurea) is a short-lived perennial member of the carrot family. In Florida, it is confined to various northern counties, south to Levy County.  It is widespread elsewhere, however, and occurs in every state and province along the Eastern Seaboard north to Quebec.  Its range extends west to Manitoba and then south to Texas.  In all of this region, it prefers moist to average sites in partial to dappled sun.
Golden alexander has deeply dissected foliage - like so many other members of the carrot family.  The basal leaves are divided twice into three leaflets while the upper leaves are single.  These leaves are maintained in warmer climates, but are deciduous where temperatures drop to below freezing.  They are maintained as a mound and this is quite attractive. As a "carrot" they are also attractive to the caterpillars of the eastern black swallowtail butterfly. 
Flowering occurs in the spring.  Like other members of this family, they are borne in flat clusters, called umbels, at the top of each stem. Each flower is tiny and bright yellow.  Normally, the flower stalks stand 1-2 feet above the basal leaves, but in the plants featured above, they are much shorter.  They are pollinated by tiny bees and flies. The ripened seeds in summer are purplish.
Golden alexander would seem to be an ideal landscape plant for Florida butterfly gardeners interested in feeding eastern black swallowtails as it does not require wet soils like so many other of its larval plants do.  It is rarely propagated in Florida, however.  I purchased my plants from Dan Miller of Trillium Gardens, Tallahassee and as far as I know, he is the only nursery in the state to offer it.  We have had our plants for about a year and I am not yet prepared to recommend it too far south of its native range.  I suspect it is adaptable to at least central Florida from what we have experienced so far. I would welcome your comments if you have tried it in your landscape.