Solutions: If the yellowing and drying of leaves and flowers is a natural progression due to age, nothing can be done to slow or stop the process. Once hormones within the plant begin the process of senescence, it’s irreversible.

Solutions: If the plant is only infected a little, it can sometimes be saved. This mainly applies to houseplants that are grown in pots. Here's what to do. Remove the plant from the pot and gently shake off as much soil as possible. Using pruning tools that have been disinfected, remove any diseased foliage and roots. Be sure the new pot has good drainage holes and wash it with one part bleach and nine parts water to ensure that it is completely clean and sanitized. Dip the plant's roots in fungicide to kill off any remaining fungal spores before potting into the clean growing medium. Only water the plant when the top inch of the soil is dry and never let the plant sit in water. For plants that are grown in the ground, it's best just to remove the infected plants and destroy them. Do not plant in the same spot until the soil has been allowed to dry out and has been treated with a fungicide.

Solutions: Bacterial infections need to be treated quickly to prevent the spread to neighboring, healthy plants, potentially wiping out large sections of your indoor or outdoor garden. In mild cases: Use sterilized (10% bleach solution) pruning shears or scissors to remove any infected plant parts, making sure to dispose of them off site. Use a copper-based bactericide to treat the unaffected foliage, as well as the soil, and neighboring plants. Follow the manufacturer’s rate and timing directions found on the product label. In severe cases, where more than half the leaves are affected: Remove all of the infected plants from the garden, disposing of them off site. Treat the soil and neighboring plants using a copper-based bactericide. Follow the manufacturer’s rate and timing directions found on the product label.

Solutions: Diseases Fungicides can prevent the transmission of spores, but they may not treat the established infection. The first step is removing and disposing of all infected plant parts. Then apply recommended chemicals. For bacterial infections, apply a spray containing copper or streptomycin. For fungal infections, consult the local cooperative extension for recommendations on which fungicides will work best. Nutrient deficiency Apply a liquid fertilizer via foliar application to fix the deficiency quickly. Follow label directions regarding dosing instructions and application notes, such as not using before the rain or when temperatures are out of the recommended range. Incorrect watering Determine the water requirements for your specific plant, and follow accordingly. Some plants like consistently moist soil, and others like the soil to dry out slightly before being watered. Pests Thoroughly apply an insecticidal soap, an organic product like neem oil, or an appropriate chemical insecticide to the plant.