We love impatiens as much as the next person, but the proliferation of downy mildew has taken much of the joy out of growing them.
Signs that your plants are suffering from an infestation of downy mildew are:
• Light green, yellowing or stippling of the leaves
• The leaves curl down along the edges
• White, downy-like growth on the underside of leaves
• Stunted growth, leaf drop and flower drop
The disease spreads rapidly by spores transmitted by splashing irrigation water and/or air currents, and primarily infects Impatiens walleriana (common garden impatiens); those with single flowers and double flowers are equally affected.
Because of this ongoing problem, many growers are decreasing their production of Impatiens walleriana, some as much as 60%. For this reason, finding this type of impatiens at all might be difficult this year. If you have your heart set on growing them, look for New Guinea impatiens or some of the other strains that have a high resistance to the disease. The Sunpatiens, Fanfare, Divine, Celebration and Celebrette series of impatiens are all resistent.
While there are fungicides on the market that will control the disease, extreme vigilance (and frequent treatment) is required. Because of this, we feel that attempting to grow many varieties of impatiens will prove to be problematic for most people.
We think the time has come to explore other options for summer color. After all, growing plants is supposed to be pleasant, right? Here are ideas for some great floral alternatives:
Dragon wing, angel wing, Rieger, tuberous or fibrous–there’s a begonia that will appeal to just about anyone. Available in almost all the colors of the rainbow (except purple and blue), they will provide you with color throughout the summer.
For an edging plant or hanging basket candidate, lobelia can’t be beat. Available in all shades of blue to white, these can be combined with other plants to create the cool feeling that only blue can provide.
Great color can be achieved with striking foliage, too:
Also called sweet potato vine, this trailer with arrowhead-shaped leaves is a great way to add purple-black, chartreuse or variegated foliage to a hanging basket.
Red, purple, pink, chartreuse, green and white–they are all available in one of the varieties of coleus–sometimes all in the same leaf!
The most well-known is coral bells but there are many others. These plants provide an accent of chartreuse, orange, peach or purple to the garden. Some have several different colors in each leaf; some sport interesting veining.