Fertilising a Spiraea × vanhouttei
To ensure the Spiraea × vanhouttei thrives, it is important to provide it with the necessary nutrients. Fertilize this shrub in early spring before the onset of new growth. Apply a balanced, slow-release fertilizer that will provide a steady supply of nutrients throughout the growing season. This is particularly important as this species develops flowers on the previous year's growth.
If the soil is not particularly fertile, consider a second application of fertilizer in mid-summer to support the lush green foliage and robust structure. However, be cautious not to over-fertilize, as this can lead to excessive leaf growth at the expense of blooms. Always follow the manufacturer's instructions regarding the quantity and frequency of fertilizer application to prevent nutrient burn and promote the overall health of the shrub.