Q: I see little things growing in my mulch that remind me of mushrooms, only they have a hollow on the top instead. They’re near my vegetable bed, so should I be worried about infection or something unsafe to eat?

A: Fortunately not — you can ignore these. Their cuplike shape gives these wee fungal mushrooms (about a quarter-inch wide) the name bird’s nest fungus, and they can be quite common on mulch. They are only breaking down the wood (and leaf litter) and won’t infect plants — nature’s recycling crew, doing their job to the benefit of plant roots that can then access those nutrients.

When rain hits those cups, the spore packets (the objects that look like eggs in the bird’s nest) are splashed out. Spores on these and similar fungi that also colonize mulch, like artillery fungi, stick to surfaces as the fungus catapults the spore packet globs away from itself, so you might see a few dark dots decorating nearby leaves or plant tags, but they’re harmless to the plants.

Q: There are dark spots on my black-eyed Susan foliage. I think this happens every year, regardless of weather. What can I treat them with?

A: The spots are probably a septoria leaf spot infection, a very common fungal disease that certain cultivars of black-eyed Susan (Rudbeckia) are more susceptible to than others. The ever-popular ‘goldsturm’ seems to be a common victim. Varieties American gold rush and little goldstar are purportedly quite resistant. Different species of septoria also infect the foliage of echinacea, tomatoes, dogwoods, heuchera, azaleas, and a wide variety of other plants. They are fairly host-specific fungi, so one plant’s infection won’t start disease on an unrelated plant; rather, they appear simultaneously due to weather conditions that allow the fungus to thrive.

Avoid wetting foliage if you need to irrigate due to dry weather. If you can’t keep the leaves dry during watering, then irrigate early enough in the day so the foliage has a chance to dry by nightfall. Prolonged periods of wet leaf surfaces are what makes plants more vulnerable to infection. You can’t do much about rain or dew of course, but plants that aren’t too crowded or planted in a spot with reduced air circulation (such as next to a house wall or solid fence) should dry sufficiently on their own.

Pick off the worst of the infected leaves and cleanup and discard (do not compost) debris from infected plants once it’s killed by frost in autumn. Occasional division will keep plants from becoming overgrown and too dense. Grow sun-loving species in full sun to support plant vigor and faster leaf drying, and select species or cultivars with good disease resistance, bearing in mind that nothing will be completely immune.

All of these approaches will reduce the need to rely on pesticides to let you grow black-eyed Susan without foliage damage, which can be significant when septoria runs rampant. For repeated severe outbreaks, it would be worth just replacing the plant with something less susceptible, like a more resistant cultivar or different species. In the rare case a fungicide would be warranted, treatments must start early (before symptoms manifest, because they cannot cure existing infections), be reapplied regularly, and be applied with thorough coverage of all leaf surfaces. Always follow label directions, and be aware that any plant visited by pollinators should not be treated since any pesticide risks harming other organisms. If treating a flowering plant, remove the flowers so pollinators won’t visit while they could be exposed to spray residues.

University of Maryland Extension’s Home and Garden Information Center offers free gardening and pest information at extension.umd.edu/hgic. Click “Ask Extension” to send questions and photos.