How to Grow Grape Hyacinth

In early spring, it's a cheerful and heartening sight when flowering bulbs signal the end of winter. Small plants collectively called grape hyacinths (Muscari spp.) are among the earliest of these spring bloomers, getting their name from the erect clusters of tiny, purple flowers that resemble bunches of grapes. Grape hyacinths are easy to grow, needing little care once they're established. Most grow in U.S. Department of Agriculture plant hardiness zones 4 or 5 through 8 or 9, depending on the variety.

Grape hyacinths bloom in spring but then become dormant during summer until early fall, when they send up fleshy, thin new leaves that help store nutrients for the next season. Because of this two-phase growth habit, it's best to plant the bulbs in the fall so that they have time to grow and prepare for the next spring's bloom.

Several species of grape hyacinths are commonly cultivated. These include the Armenian grape hyacinth (_Muscari armeniacum_, which grows in USDA zones 4 through 8), with royal blue flowers on an 8-inch-tall plant, and the azure grape hyacinth (Muscari azureum, which grows in USDA zones 5 through 8), an extra-early bloomer that's only about 4 to 6 inches tall and has bluish purple flowers. Plant these and other varieties 2 to 3 inches deep, and allow about 3 inches between bulbs.

Grape hyacinths grow best in a spot that gets full sun and do well in any type of garden soil that drains well. If your soil contains clay and tends to stay soggy after a rain or watering, mix about 2 inches of coarse sand into the planting area before setting the bulbs in place. The plant prefers organically rich soil, so amend your area with about 2 inches of compost before you plant, mixing it in with a garden fork or spade.

Once new leaves emerge in the planted area, keep the soil evenly moist, watering whenever the top inch or two of soil feels dry to your fingertip. When winter approaches and leaves start to die back, the bulb enters a dormant period until spring, so withhold extra water during this time. When spring arrives and you see new leaves and flower spikes emerge, resume watering to keep the soil lightly moist. As flowers and leaves die back at the end of spring and the bulbs enter another dormant period, again allow the soil to dry out to give the plants a needed rest.

When foliage disappears in summer, mark the area where you planted grape hyacinths with labeled sticks to avoid disturbing the bulbs.

Pruning grape hyacinths isn't necessary, but you can trim away faded flower spikes or leaves when the bulbs enter dormancy. Use small, sharp shears, wiping the blades with rubbing alcohol between cuts to prevent the spread of plant diseases.

Grape hyacinths don't require fertilization if they are planted in organically rich soil, but you can give the plants a boost by fertilizing them with an organic formula such as 3-5-3 that's intended for bulbs. Mix about 1 pound into the top few inches of soil for each 15 square feet of planted area, doing this in the fall when new growth begins.