All About Gardening and Gardening Q & A by Pernell Gerver

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"The Best of the Newest Perennial Introductions"

It's always exciting to grow something new and different in the garden. There are many new perennials that have been introduced in recent years with nice attributes. All of them can be planted any time now through fall.

Switch grass is a nice late-summer-to-autumn-blooming ornamental grass and a new variety being introduced this year is 'Prairie Fire.' It's an improved switch grass that develops deep maroon-red leaves as early as June. The deep-burgundy foliage really stands out in the garden and it's a good substitute for purple fountain grass which isn't hardy here in western Massachusetts. Airy flower panicles stand just above the foliage in late summer. It grows just three feet tall and forms a handsome clump.

Tall garden phlox is a popular summer-blooming perennial and a new variety being introduced this year is quite eyecatching. Called 'Peppermint Twist' this tall garden phlox bears large flower clusters that bear stunning bi-colored flowers. Each flower petal is bright pink with a distinct band of white running down the center, giving the flower a pinwheel pattern. The flowers bloom atop compact, 16-inch stems. It has good disease resistance.

Purple coneflower is another popular summer-blooming perennial that provides a long season of bloom. Hybridizers have been developing many nice, new varieties in recent years and one of the more outstanding introductions is the variety 'After Midnight.' It's a dwarf variety, growing just a foot tall that bears large, dark-magenta-purple flowers with a black-red cone. The flowers are fragrant, which is unique for purple coneflower. The large flowers bloom atop well-branched, blue-green foliage. Like all purple coneflowers, it'a a favorite of butterflies and bees.

Brunnera is a spring-blooming perennial that is a good choice for a shady spot in the garden. The new introduction 'Spring Yellow' combines attractive leaves and flowers. Its heart-shaped leaves are bright yellow as they emerge in spring and retain their chartreuse color nearly all season long. Airy clusters of bright-blue flowers that resemble forget-me-not flowers stand above the foliage in early to mid spring. The contrast between the blue flowers and the yellow foliage is stunning. Even after it's done blooming it remains a highlight in the shade garden.

Pernell Gerver's Gardening Q & Aby Pernell Gerver

"No Cure for Impatiens Necrotic Spot Virus"

Q. I have never had this problem before but my impatiens are dying or something. The leaves are turning yellow and have black spots. We know they are getting enough water as we water and have fertilized regularly. So what's going on? Thank you.

A. I also bought impatiens transplants at the same place you did this spring so I know exactly what problem you brought home.

The problem is called impatiens necrotic spot virus, or INSV for short. In recent years INSV has become a very serious and widespread disease of greenhouse flower crops including, but not limited to, impatiens, New Guinea impatiens, ageratum, amaranthus, amaryllis, anemone, baby's breath, begonia, calceolaria, calendula, calla lily, campanula, China aster, chrysanthemum, cineraria, coleus, columbine, coreopsis, cosmos, cyclamen, dahlia, delphinium, exacum, forget-me-not, gaillardia, geranium, gladiolus, gloxinia, hydrangea, lobelia, marigold, nasturtium, peony, petunia, phlox, poppy, primrose, ranunculus, salvia, sinningia, snapdragon, stock, tiger lily, verbena, zinnia, and over 300 others. INSV also affects certain vegetables like broad bean, cauliflower, celery, eggplant, lettuce, pea, pepper, potato, snap bean, spinach, and tomato. INSV is a serious problem facing the floriculture industry.

As you know, when you buy your plants they look fine, but later on they start looking bad and showing symptoms of the disease. INSV can look different on different plants. Symptoms you may see include necrotic (brown, dead) ring spots on the leaves, yellow circular spots on the leaves, stems may have black or brown discoloration, stunted plants, flower color breaking, leaf veins may be brown, death of the tip growth, wilting, collapse of the entire plant, leaves may have yellow line patterns in them, or there may be mosaic, variegated patterns of light and dark green in the leaves.

Years ago when I first identified this disease on plants I had bought I was told it comes in on the seed. Tiny, nearly invisible insects known as thrip spread INSV from plant to plant. Researchers say the virus may also be spread throughout the greenhouse industry by the movement of infected plants or cuttings.

Unfortunately, once the plants are infected there is no cure. The best thing to do now is to remove and throw out in the trash any infected plants and to control the thrips before they can spread the virus to other plants in your garden. I use Neem Oil to control thrips. Made from the seeds of the Neem tree that grows in India, this amazing all-natural spray is an insecticide, fungicide, and miticide all in one. It can be used on all plants including roses, perennials, annuals, trees, shrubs, flowers, fruits, vegetables, and house plants. It controls all stages of insects (adult, larvae, and egg). It acts as a growth regulator, antifeedant, repellent, and contact killer of many common and hard-to-control insect pests, including thrip.

Click here to read more about Neem Oil and order it from Pernell Gerver's Online Store.

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