Fertilize More Often For High-Quality Roses

Q. I'd like to continue fertilizing my rose bushes right through the spring since the past year's bloom was not too impressive. Is there any advantage or harm with that strategy?

A. High quality roses are typically fertilized about every 6 to 8 weeks through the winter, spring and early summer in our climate. Fertilizer applications are usually stopped during the summer months when flowering is the worst and resumes about a week before good flowering resumes.

SulPoMag conttains magnesium and can
be substituted for epsom salts

Fertilizer applications are made to support healthy, vigorous growth and flower production. The timing of these applications varies with the type of rose and variety as well as the microclimate.

Generally speaking, roses perform very well in our climate for about 8 to 9 months of the year. Microclimates that are warm and protected in the winter may support the flowering of roses through the entire winter. In these microclimates you would fertilize all winter long.

In cooler microclimates you may see an interruption in flowering during the winter but have a longer flowering period in spring and fall. Fertilizer applications would support roses during their flowering periods.

If you are fertilizing roses more often, then use smaller amounts of fertilizer or use fertilizers that release nitrogen more slowly. Make sure that your roses receive an annual application of iron that is applied just prior to new growth.

Many rosarians like to apply Epsom salts as part of their fertilizer regime for the magnesium contained in it. Other fertilizers like SulPoMag and some palm fertilizers also contain magnesium and may be an appropriate substitute.