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Island flowers

July 31, 2005|By Dorry Baird Norris

Our partially shaded garden, home to many native woodland plants, is glorious in the spring. Virginia bluebells, trillium and dogtooth violets bloom in glorious profusion. By late June, the floral color is gone, but the texture and variegated coloring of leaves still engage the eye.

The slender, silver-striped leaves of golden dead nettle, also called yellow archangel (Lamium galeobdolongleam), are in the border. Above it, the fernlike leaves of sweet cicely (Myrrhis odorata) waft gently in the breeze; tall, stiff stems carry this year's crop of long, brown, ridged seeds. At the back of the border a steadily expanding variegated Solomon's seal (Polygonatum odoratum variegatum) shed its bell-like flowers some time ago, but its long, narrow white-bordered leaves still light up the space beside an evergreen azalea.

Now that the flowers are gone, this bed could use a touch of excitement. White Wave petunias might add a light touch, but there might be too much shade for them. Impatiens don't mind the shade and white impatiens would be nice, but their leaves are somewhat dull.

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I think I'll plant the shiny-leafed Madagascar periwinkle (Catharanthus roseus). Producing elegant five-petaled flowers, it will thrive in either sun or light shade. White ones would suit the garden best.

Catharanthus roseus is eminently appropriate for an herb-themed landscape. For centuries, it has been used as a folk remedy. In its native Madagascar - a large island in the Indian Ocean east of Africa - extracts of the plant were used to treat diabetes, to lower blood pressure, to disinfectant and as tranquilizers.

In India, juice of the stems was used to treat wasp stings. A poultice made of the boiled plant was used to stop bleeding. The Chinese regarded it highly as an astringent, diuretic and cough remedy.

Closer to home, in Central and South America, it was used as a homemade cold remedy to ease lung congestion and sore throats. Throughout the Caribbean, an extract from the flowers was used to make a solution to treat eye irritation and infections. The alkaloids in this plant are powerful, but they can have serious side effects such as nausea and hair loss. Be aware that self-medication with any part of this plant is not recommended.

It wasn't until the 1950s that western researchers began to take notice of Catharanthus roseus. Two of the more than seventy alkaloids that have been identified in the plant to date, vincrinstine and vinblastine, have proved to be effective in the treatment of leukemia. Research continues on ways to make use of other alkaloids in the plant.

A tender perennial, Madagascar periwinkle, will continue producing blooms until hit by a killing frost. It may reseed prolifically and in warmer climates, like Florida, it has become a noxious weed. No danger of that here in Washington County - last year's plants in my garden produced exactly one seedling. Dead-heading is unnecessary as the old blossoms fall off and the plant cheerfully continues blooming.

Although now known botanically as Catharanthus roseus, it was called Vinca rosea when first we met. The name Catharanthus comes from the Greek meaning "pure flower." Flowers range from deep pink, rose and mauve to my favorite, white. It has also been called rose periwinkle, old maid, Cape periwinkle, red periwinkle and cayenne jasmine,

It's previous designation Vinca originated because of its resemblance to the common, blue-flowered Vinca minor, or myrtle, routinely used as a ground cover.

Current interest in Madagascar periwinkle as a landscape plant is the result of successes in plant breeding. The cultivar 'Polka Dot,' a dwarf, trailing type, won an All-American Selection Award in 1969. In 1991, 'Pretty in Pink,' 'Pretty in Rose' and 'Parasol' received the same prestigious prize.

Although Madagascar periwinkle prefers a sandy soil, I usually plant mine in window boxes in a commercial potting mix. It does appreciate well-drained soil. The plants are drought tolerant, though on hot days they do droop by mid-afternoon. They can even survive when planted in such inhospitable locations as next to the foundation of houses with south and west exposures, or next to walks and drives with reflected heat (but keep them carefully watered) as well as places like my semi-shaded garden.

You can make cuttings from your plants in late summer for over-wintering so as to provide a stock for next spring.

Every time I look at my Catharanthus roseus I am reminded that the natural world holds undiscovered treasures that may ease the ills of mankind. There's a "green pharmacy" waiting to be explored. We need to guard it carefully and use it cautiously.

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