Dormant oil application to my roses is the most important pest prevention task for me as an organic rose gardener. The dormant oil is horticultural oil diluted in water. Horticultural oil is available at most nurseries. As a dormant spray, the horticultural oil is less diluted than it is when its used after plants have leafed out.
The importance of the horticultural oil for the organic rose gardener is that it suffocates many pest and their eggs before they become active as the weather warms up. It's good as a control for aphids, spider mites, scale, sawfly, and thrips.
The dormant oil should be applied all over the canes of the roses. The easiest time to do it is after pruning because all the unnecessary wood has been removed; but, if you will not complete your rose pruning until the leaves have already begun to emerge, do it now.
The only brand that I know of is Bonide All Seasons Horticultural & Dormant Spray Oil (see photo below).
For related posts on Rose Pruning, see:
http://heirloomgardener.blogspot.com/2008/02/how-to-prune-roses-part-i-introduction.html
http://heirloomgardener.blogspot.com/2008/03/how-to-prune-roses-part-ii-old-rose.html
1 comment:
Yes, and it works well on cherry trees too. I'm glad you reminded us.
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