Dutch hyacinths are some of the world’s most fragrant flowers. They are a wonderful addition to any spring garden and are also one of the best bulbs for “forcing”. Forcing is a planting technique that lets you bring plants into bloom weeks or even months before they would normally flower in your garden. Read on for easy, step-by-step instructions.
HYACINTH BULBS NEED TO BE PRE-CHILLED
As with most other spring-blooming bulbs, hyacinths need to go through a period of cold weather (35-48°F) in order to bloom properly. Being exposed to wintery temperatures tells the embryonic flower inside the bulb that spring is coming and flower development should begin. If the bulbs are not exposed to the right amount of cold for the right amount of time, the flowers will not form properly and may not emerge at all.
HOW TO CHILL YOUR BULBS
It’s possible to purchase pre-chilled hyacinth bulbs, but they’re not always easy to find. Chilling your own bulbs gives you more control over bloom time and also gives you many more choices for varieties.You can chill your hyacinth bulbs either before or after you plant them. In both cases, the chilling period needs to last at least 13 weeks. During this time the bulbs need:
Moist soil or humid air
Consistent temperatures of 35 to 48°F
WHERE TO CHILL YOUR BULBS
In growing zones 7 and 8, winter temperatures may be cold enough to chill the bulbs outdoors. In zones 3-6, you need to protect the bulbs from the extreme cold so they don’t freeze. Consider using an unheated basement, an attached garage or porch, or a greenhouse or cold frame.Another option is to chill the bulbs (planted or unplanted) in a refrigerator. Just make sure not to store any fruit in there at the same time. The ethylene gas given off by ripening fruit will damage the embryonic flowers inside the bulbs.
WHEN TO PLANT HYACINTH BULBS
It’s difficult to know exactly when forced bulbs will bloom. For a continuous parade of spring color, choose several different varieties of hyacinths and plant a few bulbs each week between mid-October and mid-November. Bulbs planted in mid-October will bloom in February. Bulbs planted in mid-November will typically bloom in March and April.
When planted in a garden, hyacinth bulbs will usually rebloom for 2 or 3 years. Forced bulbs are usually treated as annuals and discarded after they flower.To learn about planting spring-blooming bulbs in containers for outdoor display, read: How to Grow Spring Bulbs in Containers.