Sunday, December 12, 2010

Graptopetalum

Graptopetalum

The plant pictured above is a beautifully grown succulent in the stonecrop family (Crassulaceae) at Abell's Nursery in Lake Worth, Florida. It is probably a hybrid with at least one parent being a Graptopetalum, a genus native to North America, where it ranges from Arizona to Oaxaca, Mexico.

The plant in the upper left corner of the photograph is Portulacaria afra, a member of the portulaca family (Portulacaceae) native to Africa. It is represented by two distinct forms, the typical green-leaved form and a form with variegated leaves.

© 2010 Rufino Osorio.

Saturday, December 11, 2010

Tithonia rotundifolia

Tithonia rotundifolia

Tithonia rotundifolia (Miller) S.F. Blake is an annual native to Mexico and Central America. Depending on the plant's genetics and growing conditions, it grows 3–6 feet tall. It is grown for its large, brilliant orange-red daisies, these being used as cut flowers or as a source of nectar in butterfly gardens. The plant is a serious invasive pest plant in some countries but it is not regarded as invasive in the United States, where it has sparingly escaped cultivation in Florida and Louisiana.

In my garden, plants of Tithonia rotundifolia were severely attacked by various insect pests and a plant virus almost as soon as they germinated and the severely weakened plants barely survived long enough for me to obtain the photograph above before promptly dying without setting seeds. In view of this plant's invasive tendencies in various tropical and subtropical regions, I did not consider its early demise in my garden unfortunate.

© 2010 Rufino Osorio.

Stokesia laevis – Stokes-Aster

Stokesia laevis, stokes-aster

Stokesia laevis (J. Hill) Greene is a perennial wildflower in the daisy family native to Alabama, Florida, Georgia, Louisiana, Mississippi, and South Carolina. It grows 1–2 feet tall and is distinctive for its large lavender-blue daisies which are borne in June–September. In nature it occurs in woodland openings, bogs, and wet flatwoods and savannas; however, it readily adapts to garden conditions in light shade to full sun in sites with rich, moist soil. Plants slowly form rather large clumps and it is easily propagated by division of the clumps. It may also be propagated from root cuttings and from seeds, which do not require any special pretreatments for germination. There are reports that seeds of stokes-aster may germinate irregularly over a long period of time (Gettys & Werner 2001); however, in one experiment, 78% of 985 seeds germinated within 42 days (ibid).

Stokesia laevis, stokes-aster

References:

  • Gettys, L.A. and D.J. Werner. 2001. Stratification unnecessary for germination of seeds of stokes aster [Stokesia laevis (J. Hill) Greene]. Proceedings of the Florida State Horticultural Society 114:250–251. PDF

 

© 2010 Rufino Osorio.