When you see a lichen in your flower bed, you are not looking at a single organism, but two organisms in a symbiotic relationship. Lichen is a combination of algae and filament fungus. It resembles a ruffled, blue-green slab-like structure. Although it is not harmful, lichen may be considered unsightly by some gardeners. But getting rid of lichen in the flower bed is simple.
Slide your fingers into the soil beneath the lichen, and lift it away from your garden. Discard lichen in a trash can along with weed seeds and other organic wastes that you do not wish to compost.
Add plants your flower bed so that sunlight is blocked from the location where the lichen is growing. Since lichen grows best in partial sunlight conditions, decreasing the sun that reaches this location will kill lichen growing there and keep it from returning. Conversely, taking away vegetation so that lichen is in full sun and gets more air flow will dry it out and kill it as well.
Scratch the soil lightly with a cultivating fork. Lichen will not be attached deeply, and raking the soil will dislodge it, as well as aerating the soil to prevent future growth.
Mix powdered sulfur into the ground. Powdered sulfur is a garden amendment used to lower the pH level of alkaline soil. But it is also one of the ingredients used in fungicide. A soil with traces of powdered sulfur will become a hostile environment for lichen.