Q: Part of me is eager to get my fall garden cleanup started, while part of me is happy to avoid more work if it’s not necessary. I’ve heard seemingly conflicting advice about tidying perennial beds in autumn. What should I do?
A: You’ll be happy to hear that, in general, less is more: don’t do much, especially when gardening with native plants. The main exception would be the removal of plant debris from severe fungal or bacterial infections earlier this year. While this won’t necessarily eliminate the diseases for future years, it may reduce overwintering spores and lessen the chances for an outbreak of similar severity.
Wildlife benefits from our leaving shed foliage, plant stems, and other organic debris in the garden — the more intact, the better. They serve as shelter for overwintering insects and other small animals, and the vegetation’s gradual decay will add to soil organic matter content, promoting healthy microbe populations in soil that greatly benefits roots.
If you must collect leaves, see if you can use them for another purpose, such as covering bare soil, blanketing a cold-sensitive shrub like fig (loosely piled intact in a cage around the plant) or turning them into compost. Preferably, simply move them as-is into another part of the yard to decompose, just not up against the house. Keeping them on your property will also lessen the unintentional spread of invasive organisms, like weed seeds or jumping worm cocoons.
Similarly, if perennial stems need to be clipped, try to keep them as whole as possible and lay them in a part of the yard that won’t be disturbed until late spring so any tiny bees inside can emerge unscathed. One advantage to leaving them in place is the support they’ll provide to emerging stems of next year’s growth. Dead wood on trees and shrubs can always be removed whenever it’s found, lest it break and fall later, risking damage to healthy branches or plantings below.
Q: I’m starting to see mushrooms appearing in the yard. Can you identify them, and should I get rid of them?
A: Mushrooms for fungi are akin to flowers on a plant — they’re used for reproduction, and their removal won’t eliminate or have much impact on the whole organism. That’s OK, since mushroom-producing fungi don’t often cause disease in plants, and fungi are a healthy and necessary component of soil life. Identifying mushrooms relies on fine, sometimes microscopic detail best left to mycologists (fungi experts), especially since different species can have quite similar appearances. Because of the risk of toxicity, don’t consume any wild mushroom, and if curious children or pets might sample them, either keep them out of that area or clear away those you can find. Otherwise, leave mushrooms alone and they’ll disappear soon enough on their own.
Moist conditions promote the formation of mushrooms, which is why we tend to see more after rains or in autumn (as sources of nourishment increase, plus cooling temperatures slow drying). Many of these fungi recycle organic matter, either decaying dead roots and leaves in lawn, wood mulches in garden beds, or old tree roots. Mushrooms that appear growing out of a living tree trunk are more concerning, so consulting a certified arborist in those cases would be prudent.
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.