I brought my peace lilies indoors last week for the winter, and now their young leaves have holes in them. I see webbing in the plant base and slime stuff as well, but I can't find what is doing the munching.

Examine houseplants carefully before bringing them indoors. A sharp water spray helps dislodge many potential pests, such as spider mites. Your peace lilies, however, likely harbor slugs, which chew substantial holes in foliage. Slugs hide in soil and leaf litter and come out at night to feed, leaving slime behind. You can try the usual slug control methods (a small dish of beer to drown them or an empty grapefruit half which provides a dark moist hiding place to lure them so you can catch them). It might be easier to pull the entire plant ball out of the container and conduct a slug hunt.

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I have a perennial called butterfly weed with yellow clusters of flowers. When the seed pods break, like native milkweed, lots of floating white “fairies” come out and blow around the yard. How can I grow these seeds for more plants next year?

Butterfly weed, Asclepias tuberosa, is a member of the milkweed family, big favorites of butterflies. This native flower, whose colors include orange and red, is easy to raise from seed. Seeds need no special treatment before germination. You can plant seed in-ground now as soon as the pods break open or in spring. Alternatively, start seed indoors next spring. They prefer full sun and average soil. Until planting, store them in a glass jar in a cool, dry area where temperatures don't fluctuate too much, because heat and moisture urges the seeds into activity. Don't be surprised if you get other colors than yellow.

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

Digging deeper

White turtlehead & Baltimore Checkerspot

One plant is the linchpin to survival for Maryland's official butterfly, the Baltimore Checkerspot. The young caterpillars must feed on white turtlehead. It's not that they're fussy or inflexible, but their stomach enzymes can't decide to digest something else — any more than humans can decide to exist on Astroturf. Growing into beautiful orange and black striped caterpillars with tiny black “Christmas tree” bristles, the checkerspot menu enlarges to include viburnum, English plantain (a weed), penstemon and honeysuckle. As gorgeous black and orange butterflies, they sip nectar from milkweed, mountain mint and blackberry. Checkerspot habitat is wet meadow--in short supply these days, reduced by development and deer over-browse. Eleven isolated colonies of our endangered Baltimore checkerspot exist in Maryland, needing more connective habitats in order to increase. Checkerspots overwinter in leaf litter and make messy webs, challenging us to widen our vision of beautiful gardens.

— Ellen Nibali