Growing Little Perennial Wonders
By Linda Smith
Reprinted from
The Understory, Aug.-Sep. 2004

Wildflowers have special attributes that are astounding. They show us adaptability and seasonal change. An ongoing saga can be written about their strengths. From the first sign of new growth to the resting season following seed production, they are an ever-changing marvel. they add diversity, and for the observant and curious gardener, new techniques to try.

A few principles to apply to dry-site perennials:

  • Dry site wildflowers are accustomed to Florida's sandy soils. Fertilizer will cause overgrowth and does not enhance the plant's growth pattern.
  • These plants will grow in low spots that drain, but if the area stays too wet during a rainy season they may choose to not return for another year.
  • Direct sun for six hours a day is a good formula. Full sun is also generally acceptable.
  • A light sprinkling of leaves and grass clippings each season helps to retain moisture and build organic content in the soil. Heavy mulching will inhibit reproduction and could retain too much moisture during wet seasons. If you are hoping for new plants from seeds, plant along with clumps of native grasses. The effect is similar to a light protective mulch and seeds that fall are more likely to sprout.
  • Summertime is a great time to plant. The summer rains help a lot when newly planted root balls can dry out rapidly. Fall and winter planting allows seedlings to establish good root systems before the spring and accompanying drought arrives.

Four examples of perennial wildflowers are ruellia, ironweed, beardtongue and rosinweed. These durable plants are fascinating to watch through the years. They adapt easily to sandy soils, full to part sun and do not require irrigation once they are established. Their seeds are as interesting as their flowers. Each flower is a sweet reminder of humble simplicity. Each seed is a reminder of the complexity of life itself.

Ironweed (Vernonia gigantea, V. angustifolia) grows from central Florida north through the Carolinas and West Virginia. Some species are found as far west as Mississippi. In the late summer and autumn, they are very showy. Tall stems with clusters of deep purple flowers reach about 4 feet high. In a garden in central Florida, they will return faithfully every spring and will sometimes bloom in late spring and again in the fall. Deep green leaves provide a good background. They transplant easily and require no irrigation once established.

Another tall grower is rosinweed (Silphium ?). Cultivated varieties may differ somewhat to the related aster species found in fields and roadsides. When purchased as a 4" seedling, it can unfold into a vigorous tall bloomer with lots of bright yellow flowers. Rosinweed does well in sandy soils with minimum organic content. When the blooms fade, it responds well to clipping back and will produce periodic blooms throughout the growing season. In some cases, rosinweed will grow to 5 feet tall and 3 feet wide. A light clipping here and there keeps it in shape.

Beardtongue (Penstemon multiflorus, P. australis) blooms in the spring or autumn when under cultivation. The two-foot shafts of bell-like pink or white flowers are long-lasting. The small clumps grow slowly larger through the years. When viewed close up, the flowers are amazing, with a furry bearded tongue on the lower petal reminiscent of the cousin snapdragon. The seeds mature slowly and tend not to reproduce easily. These are particularly well-suited for drier sites.

The growing and blooming season of ruellia (Ruellia caroliniensis) more than makes up for the scruffier dormant period. The delicate blue blossoms and rounded clusters of leaves and stems will make you smile and feel quite calm. As it volunteers around the yard it will enhance any bed. It often finds very appropriate places to volunteer, exactly between two small green shrubs or along the edges of the garden.

These plants have thrived nearly unattended in an "average" yard in Pinellas County. They are seasonally available through Wilcox Nursery in Largo. In some cases these common names may not exactly match species identified in field guides. That is because they are grown by specialized nurseries throughout Florida and also because they exhibit different virtues when under cultivation. Enjoy whatever they do!

Copyright 2003-2008 Florida Native Plant Society --- Revised July 14, 2006
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