Dedicated rosarians and casual gardeners alike are looking for safer ways to take care of their gardens but still keep them disease free. In the last couple of years several experienced rosarians have been experimenting with various formulas using common household ingredients. If these experiments are successful, they soon find their way into American Rose Society newsletters and then into more widespread media.

Several years ago, rosarians started experimenting with using aspirin as a type of plant growth booster. Most had very good success with it. I've used it and like the results. It's an easy and inexpensive way to keep gardens disease free.

About five years ago, Tom Miles, a Rose Society member in Washington, also began experimenting with aspirin and, over time, added other ingredients he found to be a safer alternative to fungicides. He began to spread the word and this spring the information found its way into the Portland Rose Society newsletter. The following is Tom Miles' comments on the eco-friendly rose spray.

“This spray invigorates the plant's immune system and promotes the natural growth of roses. It is eco-friendly to humans and garden helpers like ladybugs, honey bees, birds, wasps and hornets. It is an effective deterrent to significant damage by black spot, powdery mildew and rust and harmful insects like aphids, root weevils, earwigs and thrips.

This treatment was tested for one year in Lawrence Scott Park public rose garden, Kennewick, Wash., on 300 roses. It also has been tested and found effective for three years in my home flower garden in Richland on a variety of annual and perennial flowers and shrubs. Both of these sites are located in an elevated desert region in southeastern Washington State with a weather classification of Zone 6.

This spray is compatible with large populations of earthworms and night crawlers that aerate the soil and convert soil organics to valuable nutrients that enhance plant growth and health.

Spray ingredients

Four gallons of water (rain water preferred), four 325 mg. aspirin tablets, one cup apple cider vinegar (5 percent acidity), four tablespoons of Miracle Gro soluble plant fertilizer and four tablespoons of liquid dishwashing soap.

Spray prep

Add four aspirin to one cup of apple cider vinegar and let aspirin dissolve. Stir to mix and then pour aspirin and vinegar into four gallons of water in a sprayer. Add Miracle Gro and soap. Cap sprayer and shake well to thoroughly mix solution.

Spray application

A backpack sprayer with 4-gallon capacity, manual pump and a float mixing agitator was used in the large garden to minimize labor.

Less expensive small sprayers are adequate for small home gardens. It is important to have a 2-3 foot wand on sprayer hose so nozzle can be inserted in center of dense growth of roses to get good spray coverage. Use a sprayer with sufficient spray force to thoroughly wet all of the foliage including tops and bottoms of leaves.”

The recommended starting time for application of the spring cycle in our area is after last winter hard freeze around the first of May when new canes and branch buds on old canes pruned in late March start to develop. Spray should be applied as necessary to prevent disease and keep roses healthy until the first light frost occurs by mid-October and the rose plant enters the quiescent cycle.

A spray cycle of twice a month was sufficient to prevent significant fungal or insect damage when the spray was allowed to remain on the plants for 24 hours without rain or overhead irrigation. Watch for early signs of mildew during spring and fall during cold night-warm day periods and spray immediately before mildew spreads.

If you want to defeat black spot but want a safer spray, try using this mixture. You may have more limited success than Tom Miles did because our climate is cooler and more conducive to black spot but it is sure worth a try.

(Corinne Clifton lives near Bandon and grows more than 200 kinds of roses.)