It is every gardener's worst nightmare: flowers that have been nurtured from seeds; watered and weeded for weeks, even months; are wilted; covered in an unidentified substance; or chewed apart from disease, pests or poor maintenance practices. The key is to identify the problem, fix the damage and prevent it from reoccurring so your garden can be its most beautiful all season long.
Diseases can be caused by fungus, bacteria or a virus. The first step in treatment is identification. Viruses are the most destructive to plants, according to "The Complete Idiot's Guide to Gardening," by Jane O'Connor and Emma Sweeney. Some common diseases:
Blight causes the leaves or flowers to wilt, turn brown and die. Damping-off disease is caused by over-wet conditions at the base of the plant that stunt the growth of the seeds. Rot is caused by a fungus or bacteria and may be corrected by cutting back on watering. Leaf spot appears with white, yellow and brown spots on the leaves and is caused by a fungus or bacteria. Rust and mildew is a fungus that appears as a powdery substance on leaves and stems and mosaic. It is caused by a virus and present as a green or yellow discoloration of the leaves.
Fungus infections can be treated with a fungicide unless the affected area is rotted or, in the case of leaf spot, remove the infected area. For bacterial and virus diseases, discard all affected areas.
The sad fact of gardening is that many insects look at a garden and see a buffet line. The good news is that there are a number of natural ways to keep pests at bay. For insects, consider using natural predators, such as praying mantis, toads, earwigs, lacewings and toads that eat pests, suggests Richard H. Cravens in his book, "Pests and Disease." Or use parasites, such as braconid wasps, which attack the larvae of destructive pests, killing them from the inside out. Or consider planting repellent plants, such as marigolds, lavender or mint, which repel ants. Or use an insecticidal soap or lime spray on the stems to repel bugs.
For larger pests, such as rabbits and deer, consider erecting a fence or other barrier.
Thin and Sparse Growth
To encourage flowers to grow full and healthy, thinning, pinching back and feeding may be in order. Thin out annuals by removing weaker seedlings so the healthy seeds have room to grow. Pinch back annual and perennials by snipping off growing tips. This will encourage the entire plant to become fuller, according to "Taylor's Master Guide to Gardening." Deadheading annuals and perennials means to remove spent flowers, which will encourage growth in other stems. Feed annuals by applying a fertilizer after pinching them back. Perennials need much less fertilizer than annuals, so stop feeding them by mid-summer.