Homemade remedies treat black spot on roses

By Audrey Post
MS. GROW-IT-ALL

Q: What can I do about black spot on my roses? I would prefer to avoid chemicals and go with something more organic, even if it means I have to treat the rose bushes more often?

A: Black spot is a fungus, Marssonina rosae, that causes dark-colored spots to appear on the leaves, hence its name, and then the leaves turn yellow and die. It’s a common problem in areas of high humidity and frequent summer rainfall.

Some cultivars are more resistant to black spot than others, and you can keep the fungus in check by removing fallen leaves and pruning the canes in late winter (mid-February in North Florida). Avoid overhead irrigation, if possible, and water early in the day.

There are a number of fungicide products on the market, but since you want to avoid using chemicals, here are two potions that friends recommend: Mix fat-free milk and water in equal parts and spray it on the foliage; or dissolve a tablespoon of baking soda in a quart of water, add a squirt of dish soap and spray the mixture on the leaves. The soap makes it a little sticky so it adheres to the leaves. Whichever one you choose, you’ll have to apply it regularly, at least once a week, if not more often.

If readers have other suggestions, send them to the e-mail address at the bottom of the column and I’ll share them.

Plant giveaway: Jerry Patton, the Tallahassee gardener who gave away numerous plants last year, including daylilies, crape myrtles, hollies and night-blooming cereus, has another “crop” ready to share.

“I just can’t throw any plant away,” he said. “I trim them and plant the cuttings.”

This year, he has lots of night-blooming cereus, which he ran out of last year, as well as century plants (Agave), passion vine (Passiflora) and butterfly milkweed (Asclepias). He also has what he calls a “mystery plant” or two, nice potted plants but he doesn’t know their names.

Call him at 850-878-1321 for directions to his home.

Internet Radio Show: Ms. Grow-It-All’s Internet radio show on the Free World Radio Network will broadcast live at 6:30 tonight. Leon County Forester Stan Rosenthal and I will discuss lightning and gardening. Go to http://www.blogtalkradio.com/Ms_Grow-It-All and click on the link to listen live; you can call the number on the site to join the conversation. If you can’t join us, all shows are archived and available for download from my Web site.