Hyacinth

About Hyacinth

Hyacinths are spring bulbs with one thick spike of very fragrant, starry flowers per bulb. They are grown in beds and pots and are a favorite bulb for forcing indoors in winter (NC State, Missouri). The bulbs can make skin itch, so wear gloves when planting, and every part is poisonous if eaten (NC State, Oklahoma State).

NC State lists zones 4-8 and suggests winter mulch in zone 4. In coastal South Carolina, chill the bulbs in the refrigerator 6-8 weeks before planting (Clemson).

When to plant

Timing is counted from your average last spring frost (and first fall frost). Sow & Tell works out the actual dates for your ZIP code.

Plant bulbs in fall: mid-September to mid-October in Minnesota (UMN), and in South Carolina once the soil at planting depth stays below 60 F (late October-November in the upper Piedmont, late December-early January on the coast). Set them 4-6 inches deep and 3-6 inches apart, and wear gloves (Clemson, Oklahoma State).

Soil

Well-drained soil rich in organic matter; bulbs rot in soggy ground. Keep the soil moist after planting, then water less after bloom as the bulbs go dormant (NC State, Clemson).

Plant in well-drained soil; for long-term beds without a soil test, mix a slow-release complete fertilizer or bone meal into the rooting area, and keep the pH about 6-7 (Clemson).

Feeding

• Fall, at planting (permanent beds): bone meal plus balanced fertilizer such as 10-10-10, or slow-release complete fertilizer. Mix into the root zone: bone meal plus 1-2 lb of 10-10-10 per 100 sq ft, or slow-release fertilizer at the label rate (Clemson). Follow a soil test.
• Late winter or early spring, as shoots come up: balanced fertilizer such as 10-10-10. Scatter 1-2 lb per 100 sq ft and water it in (Clemson).

Avoid high-nitrogen fertilizer and fresh manure, which can lead to bulb rot (UMN). Don't cut the leaves until they brown, at least six weeks after bloom (Clemson).

Harvest

Hyacinths bloom in early to mid-spring (April-May) for 2-3 weeks (NC State). Cut off the flower spike as soon as it fades so the bulb saves its energy, but leave the leaves at least six weeks or until they brown (Oklahoma State, Clemson).

Varieties (14)

Extension sources we could open document 14 hyacinth cultivars and forms; the Missouri list groups them by how early they force indoors.

Pests to watch for

Narcissus bulb fly

Diseases and problems

Bulb rot

In the kitchen

Safety: Poisonous if eaten, the bulbs most of all; it can cause stomach cramps, drooling, vomiting and diarrhea (NC State: medium severity). Handling bulbs can irritate skin, so wear gloves or wash hands after planting (NC State, Oklahoma State).

Pets: Toxic to dogs, cats and horses (ASPCA): can cause severe vomiting and diarrhea, sometimes with blood, plus depression and tremors. Bulbs are the most toxic part (NC State).