We visited the Portland Rose Garden this weekend, and I had a chance to chat with the head botanist. He was cleaning out the rose beds and raking in mulch. I asked him when they begin fertilizing their roses.

He told me that they usually begin about mid April, but because this has been such a cold and wet spring the roses are behind in their normal growth. His guideline is to wait until there are 3-4 inches of growth on the roses.

I've heard the "six weeks until bloom" guideline, but not the "3-4 inches of growth" guideline. Maybe 3-4 inches of growth means that there will be roses in six weeks.

What benchmark do you use to begin your fertilizing?

Do any of you all use soil temperatures as a guideline?

When using all organics it probably doesn't really matter so much; it converts to nitrates over time. But using synthetics is a little different. I'm curious as to what you all out there do.

thanks for any input.