Many thanks to Joanne Messer from Tisdale for calling me up and asking for some alternative methods for troubles she is having with her roses as that conversation enticed me to write this column.
This is a challenging summer for gardeners everywhere with monsoon rains, flooding, cool temperatures and most likely sweltering heat to come.
Roses seem to be one plant in the garden that attracts a great variety of pest and disease problems. Sometimes these problems can easily be managed by just pruning off the infected parts or by physically removing the pest itself, but here are some hints to help you more sustainably have roses that are beautiful.
If you are having trouble with aphids, mites, scale or whiteflies on your roses, here are some options for making those problems go away in a safe manner.
A solution of a half teaspoon of any type of dish soap with a teaspoon of cooking oil in one quart of water is a great spray for a variety of pests. It is important to spray when the problem is small to get good control. Also, it is beneficial to spray off the plant with plain water about 30 minutes after applying to ensure the plant does not desiccate as much.
This year powdery mildew is a big problem. I suspect blackspot and rusts will also rear their ugly heads. Mixing a solution of one tablespoon baking soda with one teaspoon of cooling oil in one gallon of water will help immensely with these troubles. Spray your plant liberally with this spray and repeat as needed. It also helps if you remove any infected leaves and destroy them while at the same time keeping the ground underneath the rose free of debris and weeds. If you are just having a problem with powdery mildew, spray the leaves each morning with cool water and allow the sun to dry things off.
There have been a number of calls to try to deal with slug problems. They cause so much damage when conditions are right. One of the best ways to control slugs is diatomaceous earth. It is the jagged skeletal remains of microscopic creatures that effectively lacerates soft-bodied pests like slugs thus causing their demise. It is a powdery granular material that can be sprinkled around the garden beds or individual plants and can even be mixed with water to make a foliar spray. Be careful when using this product as it can irritate your eyes and lungs. Purchase the natural or agricultural grade to ensure the best control.
Remember slugs are most active at night so adjusting when you water may be an effective fix. Avoid watering in the afternoon and evening and instead water early in the day. If you do this and we do not get rain, then the soil surface will be dry by evening and the slug damage is greatly reduced.
If you eat grapefruit, then another easy way to get rid of the slug population is to place your half grapefruit rinds upside down where the slugs like to be. They will congregate in the masses in the rind and you can simply pick up the rind and toss it in the garbage each morning.
One last remedy is a bit gruesome so beware readers! Mix up a 10 per cent solution of isopropyl alcohol and water in a spray bottle. Lay some boards down on the ground where slugs are a problem so they are there overnight. The slugs will congregate on the bottom of the boards overnight. In the morning simply flip over the boards and spray the slugs liberally with your alcohol solution and they will shrivel and die before your eyes.
- Hanbidge is a horticulturist with the Saskatoon School of Horticulture and can be reached at 306-931-GROW(4769); by email [email protected] or check out our website atsaskhort.com
