Spirea offers spring blooming as well as summer blooming varieties. Spring blooming varieties flower from May to June, while summer blooming varieties develop flower buds in the spring and flower from July to September. Spring flowering blooms on old wood from the growth of the previous year. If you are not getting blooms, consider these possibilities:
• it is not getting enough daily sunlight. This plant requires full sun each day or more than 6 hours of direct sunlight. The shrub will continue to grow in partial shade, but you will get more foliage growth and not as much blooming.
• Improper timing of plant pruning: pruning should be done just after the first set of blooms are spent. For example, since the dormant spring bloom developed last year, pruning before it blooms would accidentally remove the flower buds, especially if it is during spring time. Or, if you prune a summer blooming variety in the spring, you may cutting off the flower buds before they open.
• A harsh winter could damage the previous season’s buds, causing them to not flower.
• Spireas may reduce or eliminate blooms if the soil is over-fertilized so do not use high-nitrogen fertilizers or apply fertilizers earlier than the product requires.
• The soil is extremely acidic or very alkaline. Consider amending the soil to see if the soil pH is preventing the uptake of nutrients.
For a spring blooming spirea, you can prune about 1/3 of the plant after blooming. If you have a summer-blooming spirea, give it a light trim after blooming to remove the old blooms and do any hard pruning in late winter.
