Mushrooms can spring up among your flowers, especially after a heavy rain. Though they pose no threat to your flowers, you may find mushrooms unsightly thanks to their bulbous growths and brown and black hue. Implement a variety of proactive and reactive strategies to make your flower beds inhospitable to mushrooms and prevent these fungi from taking over your flower bed.
Trim overhanging trees, shrubs and flower foliage to increase the sunlight in your flowerbeds. Mushrooms prefer shaded growing environments.
Reduce watering your flowers as much as possible. Mushroom spores need moist soil to grow, and drying out the soil can dehydrate existing mushrooms and prevent the growth of new mushrooms.
Remove all organic waste from your flowerbed. This includes fallen foliage and rotting mulch. Such waste material provides food for mushrooms.
Put on gloves and remove any mushrooms as soon as they emerge. Mushrooms spread by spores, and collecting the mushrooms helps prevent the spores from continuing to spread. Over time, the mushrooms' presence should decrease dramatically.
Apply a fungicide formulated with iron sulfate and intended for mushroom and lichen growth. Administer according to the label's guidelines, as toxicity varies by product. Fungicides will have little effect on mushrooms that are already growing, but will help kill any surface spores.
Remove the top 3 to 4 inches of topsoil in your flower bed, using a spade. This helps get rid of any dormant mushroom spores lying in the soil. Reserve this step when all other methods of mushroom minimization and removal fail.