Fertilising a Hibiscus syriacus 'Oiseau Bleu'
For optimal blooming and growth, Hibiscus syriacus 'Oiseau Bleu' benefits from a regular fertilizing schedule. Begin feeding in early spring, as new growth appears, using a slow-release fertilizer formulated for flowering shrubs. This initial application will support the shrub's needs throughout the vigorous growth period leading into summer.
A second application of fertilizer should be made in midsummer to sustain the plant's energy as it enters its peak flowering months from July to September. When applying fertilizer, ensure it is evenly distributed around the base of the shrub, avoiding direct contact with the stems and foliage to prevent burn.
Watering the shrub after fertilizing helps to integrate the nutrients into the soil, promoting their uptake by the root system. Adhering to this fertilizing regimen will contribute to the vibrant display of blue, purple, and pink blooms characteristic of this species.