The usual way to plant grape hyacinths (Muscari spp.) is by planting bulbs in fall. Those plants will bloom the season after planting. Grape hyacinths can also grow from seeds, and often self-seed themselves in the garden. If you don't mind waiting a few years for the plants to mature, growing from seed can be a more cost-effective way than bulbs to cover large areas or introduce these plants to your garden.
If you don't deadhead the plants after blooming grape hyacinths will reseed themselves and spread on their own. Some species self-seed so rapidly that some people remove the spent blooms after flowering to prevent them from spreading.
Certain species self-seed more readily than others:
- American grape hyacinth (Muscari armeniacum) and broad-leaved grape hyacinth (Muscari latifolium) self-seed freely and they also spread as the bulbs multiply. Both of these plants have purple flowers and grow in U.S. Department of Agriculture plant hardiness zones 4 through 8.
- White grape hyacinth (Muscari botryoides 'Album') grows slowly and is much less likely to self-seed. This cultivar has white flowers and grows in USDA zones 2 through 8.
When grape hyacinths self-seed, or you plant seeds to start grape hyacinths, it takes several years for the plants to mature. Grape hyacinths grown from seed generally flower in their fourth year.
Growing From Seed
Most species of grape hyacinths need a period of cold to grow, so starting the seeds in a cold frame instead of indoors is one way to provide a chilling period. This works in any zone where the grape hyacinths you're growing are hardy.
Plant the seeds in spring right after they ripen on the plants, or in fall if you purchased seed at the end of the growing period. Fill 6-inch pots with a rich, well-drained sterile potting soil mix. Scatter the seeds over the soil surface and run your fingers lightly over the potting mix to settle the seed. Use a pot that has drainage holes.
Prop the cold frame open on warm days, and water the pots frequently enough to keep the soil evenly moist but not soggy. Close the cold frame over winter, and only water enough to keep the soil from completely drying out. Next year, prop the cold frame open in spring so the plants can get used to outside temperatures.
After the hyacinths go dormant in midsummer, pot-up the tiny bulbs so each 6-inch pot has two or three plants. Plant the bulbs 1 inch deep in the new pots. Let the grape hyacinths grow in the cold frame for another two or three years before moving them to the garden during their summer dormant period.