The perennial hyacinths that produce such vividly bright and intensely fragrant flowers in outdoor spring gardens are also well-suited for growing indoors. Hyacinthus is a small genus comprising several species of bulbous plants, but virtually all garden varieties are cultivars of Hyacinthus orientalis. The species is also commonly known as Dutch hyacinth or simply garden hyacinth.
The pure species plant produces piercingly bright purple flowers clusters on racemes that emerge from a small, arching cluster of strap-like leaves, but there are also cultivars that produce pink, red, blue, yellow, coral, or white flowers. Outdoors, hyacinth is an early spring bloomer, but when grown indoors it is often forced into seasonal bloom by chilling the bulbs before planting.
Hyacinths contain alkaloid compounds that are toxic to humans and animals. The toxins are most concentrated in the bulbs, with the flowers and leaves containing only small amounts. Consuming the bulbs is potentially fatal, and some people experience skin irritation from handling them. Dogs and cats ingesting leaves and blooms sometimes experience stomach upset and other symptoms. There are cases of dogs dying after eating several hyacinth bulbs, but pet fatalities are not common.
|Common Name||Hyacinth, garden hyacinth, Dutch hyacinth|
|Botanical Name||Hyacinthus orientalis|
|Plant Type||Perennial flowering bulb|
|Toxicity||Toxic to humans, animals|
Can You Grow Hyacinth Indoors?
Hyacinths are not typically grown as a perennial houseplant, but they are easy to grow indoors provided you can tolerate their intense fragrance, which some people find overpowering. After flowering, the foliage is nondescript, and most gardeners treat hyacinths as seasonal annuals. Many gardeners buy new bulbs each year, chilling the bulbs and potting them on a timeline that ensures winter or early spring blooming, then discard the bulbs after the flowers have faded.
How to Grow Hyacinth Bulbs Indoors
To bloom properly at the time you wish, hyacinth bulbs must be chilled in a dark place at a temperature of 35 to 48 degrees Fahrenheit for at least 13 weeks. You can chill the bulbs either before or after you plant them in pots. In certain climates (USDA hardiness zones 7 to 8), you can store the bulbs outdoors for this chilling period. In zones 3 to 6, it works to store them in an unheated garage or porch or in a refrigerator. But for refrigerator chilling, be sure not to store the bulbs alongside fruit, which gives off ethylene gas that will ruin the flower embryos inside the bulbs.
Determining the right chilling and planting time can be tricky if you're intent on blooms at a specific time. If you start chilling bulbs in early November, you can expect blooms in the first half of March, but for Christmas blooms, you'll need to start the chilling considerably earlier, in late summer.
After the bulbs have been chilled and planted, place the potted hyacinth bulbs in a relatively cool, dark location until the sprouting leaves are about 2 inches tall, then move the container near a window that receives indirect light. When the bulbs begin to show color, move them to a full sun location for the entire bloom period.
Temperature and Humidity
Hyacinths generally prefer cool temperatures, such as those found outdoors in early spring. Keeping them in a cool location will prolong the bloom time.
Keep soil moist as the bulbs are sprouting and establishing roots, but taper off watering when blooming starts, especially if you plan to replant the bulbs outdoors.
Bulbs already have the embryo of next year's flowers inside them, so it's not necessary to fertilize them at planting time, However, a small dose of bone meal or bulb food will help bulbs form next year’s embryo when flowering is finished. Do not overfeed hyacinths; in general, bulbs are not heavy feeders.
Pruning and Maintenance
If you are treating hyacinths as annuals, simply discard the bulbs and soil when the flowers have faded. If you want to plant the bulbs outdoors, set the pots in a cool, dark location and allow the foliage to dry and die back. Then remove the bulbs and plant them outdoors when the soil warms. The bulbs will not bloom in the first outdoor season, but once they go through their next winter chilling period, you can expect the bulbs to bloom for at least two or three years.
Container and Size
Hyacinths are well suited for bulb pots, ideally made of terra cotta. With their broader base and shorter height than standard pots, bulb pots are specifically designed with top-heavy forced bulbs in mind. A four-inch diameter pot is large enough for a single bulb, and you can usually fit three bulbs in a six-inch diameter pot.
Potting Soil and Drainage
Use standard good-quality sterile potting soil. Make sure the pot has drainage holes, but there's no need for a layer of gravel in the bottom, nor is it necessary to set the pot in a tray of pebbles to assist with drainage. Ordinary potting soil is usually porous enough to prevent the bulbs from rotting, provided the pot has drainage holes.
Potting and Repotting Hyacinth Bulbs
Fill the bulb pot about halfway with potting soil, and place each bulb with the pointy side up and root side down in the soil. Add potting soil until the tips of the bulbs are exposed. Make sure the bulbs are not totally buried. Then gently push down the soil, so it is at least 1/2 inch below the rim of the pot. This prevents the soil from washing out during watering. Finally, water the pots thoroughly. Once the leaves start growing, you can expect flowers in about three weeks.
Moving Hyacinths Outdoors for the Summer
Forced hyacinths are usually treated as annuals and discarded after the bloom period. However, you can dig up the potted bulbs and replant them outdoors if you live in a climate where they will receive the required winter chilling period (USDA hardiness zones 4 to 8). But it does not work very well to bring them back indoors for another indoor growing season.
Bulbs planted outdoors after indoor forcing will normally not flower for a full year until they've gone through another winter chilling period.
Growing Hyacinths Without Soil
Hyacinths can also be grown in water in specially-designed hyacinth glasses. Hyacinth glasses are shaped like an hourglass which allows the bottom of the bulb to stay dry and the roots to be in water.
Another soilless way to grow hyacinths is to fill a shallow dish or bowl with two to three inches of pebbles. Place the bulbs on top of the pebbles, pointy side up and root side down. Then, fill the dish or bowl with more pebbles, just like you would with soil, until only the top third of the bulb is visible. Pour in enough water so the bottom of the bulb sits just above the water; roots will form and grow down into the water. Make sure the bottom of the bulb is not sitting in water or it will rot. Keep the water constant at that level, refilling as needed.
The temperature and light requirements are the same as for hyacinths grown in potting soil.
Where do hyacinths originate?
Hyacinthus orientalis is native to cooler regions of central and southern Turkey, northwestern Syria, and Lebanon.
Are there recommended cultivars?
Although there were once almost 2,000 cultivars in production, today there are about 50 that are commonly available. Some favorite varieties include "Anna Marie', 'Blue Festival', 'Blue Star', 'Carnegie', 'City of Haarlem' (a yellow variety), 'Gipsy Queen' (coral), 'Miss Saigon', 'Purple Sensation', "Woodstock', and 'White Festival'.
Can you grow hyacinths from collected flower seed?
It is a practice best attempted by serious gardeners, but yes, it is possible to collect the tiny seeds from hyacinth flowers and grow them yourself. But be patient, as it can take several years of careful tending in an outdoor location before the plant produces a sizable, viable bulb. Remember that they must receive a long chilling period each year.
Do hyacinths produce offset bulbs?
Hyacinths produce tiny offset bulbs that you might find attached to the base of the plant once the foliage dies back. These offset bulbs can be carefully split off and replanted, though it often takes a few growing seasons for the bulbs to grow to a size capable of producing notable flower stalks. This is the method by which commercial growers propagate hyacinths.