Holes in basil leaves

Q: The leaves on my basil plant have been eaten by something. There are holes in the middle of most leaves. Rona Balser, email

A: The holes could be caused by slugs, snails or caterpillars. To differentiate, put a saucerful of beer near the plant base one evening and check on it the next morning. If slugs or snails are drowned in the beer, repeat the process for several nights until you capture no more. If slugs or snails are not present, caterpillars must be the culprit. Spray the leaves with organic Bacillus thuringiensis insecticide.

Q: Our one-acre pond is becoming clogged with masses of parrot feather. Although it's an attractive plant, it's beginning to take over. How can we get rid of it without harming our fish? Jeanie Marx, email

A: Aquatic plants are divided into four groups: algae, floating plants, submerged plants, and emergent plants. Each type is controlled differently. Parrotfeather is a rooted, submerged perennial plant that usually grows in shallow water. It can be controlled by regular raking out or by chemical methods. I have a pond weed identification link plus the latest UGA weed-control recommendations at bit.ly/GApondweed.

Q: I am starting a community garden with raised beds. I need tips on how to manage it. Mary Ann Fisher, Cobb County

A: Becky Griffin is a UGA garden expert who blogs about community gardening at bit.ly/UGAcommunity. There you'll find timely tips plus excellent notes on how to start a community garden.

Q: Our 'Erie' viburnum failed to bloom in May. Should it be pruned heavily? When? Chuck Elkins, Conyers

A: Like mophead hydrangea, 'Erie' viburnum blooms on twigs that form the previous season. Your shrub's flower buds must have been frozen off in winter. Don't prune now. Wait until after spring flowering if the shrub needs pruning.

Q: I have tall crocosmia flowers. Can the seeds be saved for starting next spring? When should they be thinned out? Ellen Richards, email

A: Plant crocosmia seeds now, mimicking the natural cycle of the plant. In a good location, your spring sprouts may produce flowers next summer. You can dig the bed and thin out plants in winter.

Q: Something is eating holes in the buds of my hybrid tea roses, and there is a brown, sticky substance leaking from the holes. Gerri Dunne, email

A: Various caterpillars bore into rose buds at this time of year. Sticky sap oozes from the wounds. They can be controlled with organic sprays that contain Bacillus thuringiensis or spinosad.