How to Plant, Grow, and Care for ‘Delft Blue’ Hyacinths

Hyacinths surprise and delight in spring with their colorful, fragrant blooms. Dense along the stem, the tufted florets of ‘Delft Blue’ hyacinth in rich lilac-blue rise above bladed foliage. The pigment-saturated blooms carry a wonderfully sweet scent to enchant the senses.

‘Delft Blue’ hyacinth is a 1944 heirloom and reliable performer with frothy, loaded stems that float amongst the bladed leaves. The Dutch cultivar is a Royal Horticultural Society Award of Garden Merit recipient and flowers for several recurrent seasons of color.

Carefree, ’Delft Blue’ hyacinth grows with little tending. They’ll form waves of blue in large drifts or soften the front of the border in pockets. They make exceptional container and window box features and are excellent specimens to force indoors for even earlier winter flowers. Pair them with tulips and daffodils for a cheerful mid-spring show.

What are ‘Delft Blue’ Hyacinths?

Hyacinths are ancient bulbs, appearing in the writings of Homer and Virgil, and whose cultivation spans more than 400 years. They were among the most sought-after bulbs of the 18th century, rising in popularity in Victorian-era gardens and greenhouses with hundreds of cultivars in circulation.

Hyacinthus orientalis is a bulbous herb in the Asparagaceae family. The once-vast selection has winnowed to about 50 cultivars available today. They flower most vigorously in their first growing season, offering a burst of color and fragrance in spring’s warming temperatures.

Renowned Dutch flower breeder J.W.A. Lefeber introduced the cultivar ‘Delft Blue’ at the end of World War I. With its rich blue pigment, the long-time favorite takes its name from heritage Dutch porcelain, Delftware, in crisp blue and white.

Situate hyacinths where you’ll enjoy their fragrance in addition to the colorful florets. Along a walkway, in porch or patio planters, or at the front of the border creates a sensory experience.

Hyacinths make lovely woodland edge plantings, naturalizing under tree canopies in dappled sun. Plant them en masse for a sweep of color and perfume. They also perform well in pots with other bulbs and underplanted among cool-season annuals for a pop-up surprise when conditions suit in spring.

Characteristics

‘Deflt Blue’ hyacinth has dozens of florets clustered along a central flower stalk. Dense on compact stems, the tubular florets reflex slightly for a graceful but stiff, structural look. Three to four strappy leaves in glossy green form an attractive base.

‘Delft Blue’ hyacinth is an excellent variety for forcing indoors for early winter blooms. In the landscape, it flowers for two to three weeks in mid-spring. Hyacinths show the fullest blooms in their first growing season. ‘Delft Blue’ hyacinth often flowers for four or five years, with the second year and beyond showing sparser, more spaced-out florets along the stem. Replant every two or three years, or enjoy a less rigid look to the pretty blooms.

Whether forcing blooms in pots or growing them in the landscape, hyacinth bulbs require cold exposure for at least 10 weeks. This chill time with consistent temperatures at 40 to 45°F (4-7°C) for these weeks triggers growth when temperatures warm.

With few pest and disease problems and drought tolerance, the low-maintenance bulbs have few demands. The intensely fragrant flowers attract bees for their nectar, and a single bloom fills a room with fragrance.

Hyacinths, especially the bulbs, contain toxic alkaloids if ingested and can cause minor skin irritation. Wear gloves when handling and planting the bulbs to prevent an allergic reaction. The toxins repel foraging mammals like deer, rabbits, and squirrels.

Native Area

Hyacinths are native to Europe and Asia, particularly southern Turkey, Syria, and the Mediterranean. They thrive where summers are arid and warm, and winters are cool and wet. They enter dormancy after spring flowering as temperatures rise.

Planting

Spring-flowering bulbs are easy to plant, making quick work toward the rewarding show. Plant hyacinth bulbs in fall when soil temperatures begin to cool and nighttime temperatures are in the 40s and 50s℉. This is the best time to plant Hyacinthus and other favorite spring bulbs.

Whether planting them in the ground, in containers outdoors, or to “force” them for indoor flowering, October is prime time for many areas. The warm start gives roots time to develop before soils freeze. The cool temperatures that follow allow the necessary chill period.

When sourcing bulbs, opt for large ones for the strongest overwintering and flowering. Plant them in groups, whether in high numbers in drifts or several bulbs in a pocket (at least 6 to 15). Space the bulbs about five inches apart and four to five inches deep. Situate the bulb on its broad base with the stem-end pointed up.

The compact bloomers grow well as container features and like to be crowded in a pot. Situate them shoulder to shoulder. A high-quality potting mix offers loose, lightweight, well-draining soils suited to container culture.

Transplanting 

Fall is optimal for dividing and moving hyacinths, though you can also do so in spring after they flower. Water the bulbs after transplanting, but avoid regular irrigation. Natural seasonal moisture is sufficient for dormant bulbs.

Forcing Early Blooms

Like daffodils and tulips, hyacinths forced in containers initiate early flowering. You can force them in pots indoors with pre-chilled bulbs from a grower, or outdoors to achieve their chill period.

Pre-cooled ‘Delft Blue’ hyacinth bulbs planted in fall bloom early, usually around holiday time. Those started in pots outdoors are brought inside after their chill requirement and flower around Valentine’s Day.

To force bulbs, partially fill a container with well-draining potting media, and place the bulbs about two inches apart in the pot. Plan to leave one or two inches of headroom beneath the rim. Situate the top of the bulb about an inch below the soil surface. Water well until it pours through the pot’s drainage holes.

For pre-chilled bulbs indoors, keep them in a cool space (about 60°F or 16°C) with bright light out of direct sunlight. Move them to their display area when they’re almost ready to flower. Keep the blooms cool at night to prolong flowering, keeping them away from sunlight and heated drafts to extend flowering.

For hyacinths to achieve their chill time (which aren’t pre-cooled from a grower), plant them in early fall and place the pots outside a few weeks before the first anticipated frost. An unheated garage, basement, cold frame, or greenhouse works well, too.

If outdoors, nestle them close to a building or wall under a layer of leaves. They’ll receive adequate seasonal moisture. If indoors or undercover, keep the soil moist, but with minimal watering sessions to avoid soggy conditions.

Move the containers indoors by mid to late January to continue developing for blooms in a few weeks.

How to Grow

Hyacinths are unfussy perennial bulbs. In the proper growing conditions, the easy-care blooms need only minimal maintenance and don’t require extra resources to form small colonies.

Light

‘Delft Blue’ hyacinth performs best in full sun with six or more hours daily. They also flower in partial shade, with four or more hours of sunlight. Winter sun promotes the best growth and flowering, with too much shade showing fewer blooms.

H. orientalis grows well in open expanses and also under deciduous trees, which provide winter sun during the active growing season and cooling, dappled shade with leafy growth as temperatures warm.

Water

Provide regular moisture immediately after planting and during the growing season. Take care to avoid prolonged saturation, which can lead to bulb rot. Hyacinths usually don’t need supplemental irrigation with average seasonal moisture.

Hyacinths don’t need extra moisture during dormancy in summer, fall, and winter, and are drought-tolerant once established (their naturally arid habitats experience dry summers). Reduce watering after the bulbs bloom and as foliage fades, stopping supplemental watering a few weeks after flowering.

Soil

Good soil drainage is essential to avoid bulb rot. Evenly moist, well-draining soils provide the best support during the growing season, erring on the drier side during dormancy.

To amend lean or heavy soils, topdress the entire planting area with compost. Incorporate it as you nestle the bulbs, or turn it in lightly before planting. In poor soils like clay, add a generous amount of organic matter to increase aeration and drainage while providing nutrients. For potted specimens, use a high-quality, well-draining potting mix.

Temperature and Humidity

The Mediterranean-climate dwellers are hardy in USDA zones 4 through 8. They thrive in cooler zones, but mulch for winter protection in zone 4 adds insulation against frigid conditions.

Fertilizing

Organically rich soils with fresh compost in fall may need no additional fertilizer. For perennial bulbs, a boost in spring helps bulbs uptake and store energy for additional seasons. 

Apply a balanced, low-grade fertilizer (like a 5-5-5) as the growth tips emerge in spring. Avoid getting fertilizer on the tender, new foliage, and give a cleansing rinse after applying.

Maintenance

Hyacinths bloom for several years if left in the landscape, though their vigor declines. They revert to species characteristics over time, with smaller, less dense blooms in subsequent seasons. To foster blooms for the next year, cut off flower stalks as soon as they fade. Removing the spent flowers prevents the plant from directing energy into seed production. Energy reserves build in the bulb instead.

Let foliage naturally decline after flowering. Leaves continue to photosynthesize and direct nutrients to the bulbs for storage. The stores promote successful overwintering and future growth. Clip the leaves or leave them as natural mulch when they’re completely yellow or brown.

Weeds become competitors for nutrients during early, active growth, and hand weeding often benefits the bulbs.

Propagation

Hyacinths propagate most easily by division. If colonies become crowded, dividing increases growing space while expanding the collection.

Division

To move and divide ‘Deflt Blue’ hyacinth, dig about six inches away from the bulb or cluster of bulbs. Dig the shovel, spade, or fork deep enough to lift the bulbs with a push. Separate any bulbs into singles or smaller clusters for transplanting.

Small baby bulbs are attached to the mother bulb; if they’re ready to grow independently, they’ll separate easily with a tug. If not, leave them attached to continue growing and plant the group together.

Common Problems

‘Delft Blue’ hyacinth is generally free of serious problems like pests and diseases. Acquiring bulbs from reputable growers and inspecting them before planting helps limit pest and disease problems.

Pests

Slugs and snails may feed on tender new growth, buds, and blooms. Hand-pick them early in the day or evening when they’re most active. In the middle of the day, they’ll tuck in under leaves or on the soil around the base of the plants.

If numbers increase, bait them with beer or soda traps by filling a shallow dish and placing it at soil level.

Frequently Asked Questions