Typically, grape hyacinths don't need a lot of care after flowering, as no fertilizer is needed, pruning is not required when the plants are flowering and natural rainfall patterns provide adequate water. However, when the flowers die, it is best to trim the plant back to promote new growth.
To trim back grape hyacinth plants, trim back the flower spikes on plants that have wilted or have dead flowers by cutting the stem just below the lowest set of flowers on the spike. Plants that are yellowing and dying naturally should be cut back to ground level. While pruning is not needed during flowering, it does not harm the plant either. Always disinfect pruning shears with 1 part bleach to 9 parts water to avoid spreading any diseases to the garden area.
Grape hyacinths grow well in sun or mild shade but do not do well in extremely wet or dry environments. They also spread very easily, meaning it is best to be careful when planting because the plant can become invasive. To plant grape hyacinth bulbs, loosen the soil and remove any rocks or roots from the area. Plant the bulbs in groups of 10 or more, 2 inches apart and twice as deep as the bulbs are tall.