How to Grow Hyacinths
Typically it’s observed that flowers that look beautiful and come in a variety of colors don’t usually have a fragrance. However, some flowers are exceptions to this phenomenon and a great example of this is hyacinths.
Hyacinths not only occur in an amazing range of colors from soft blue to bright pink, but also have a sweet fragrance that makes them a much sought-after flower.
Their racemes (clusters) also come in a variety of arrangements i.e. from loose to dense and from single or double flowers. No wonder, any gardener who wishes to make their garden look beautiful would want to grow hyacinths.
Published: January 2, 2021.
Hyacinths are native to the eastern Mediterranean region, Asia Minor, and some parts of the Middle East and grow around 6 to 12 inches tall and 4 to 9 inches wide. Each hyacinth bulb produces thick stalks with 4 to 6 narrow upright leaves and 1 to 3 spikes of star-shaped reflexed flowers in pink, blue, purple, white, peach, lavender, apricot, orange, yellow and red colors. Hyacinths come even in black color but very rarely.
Hyacinths belong to the Asparagaceae family and its botanical name is Hyacinthus orientalis. It was introduced to Europe in the 16th century and Dutch bulb growers were so attracted to the beauty and colors of the flowers that they started breeding them and bred over 2,000 cultivars by the 18th century. However, today in commercial cultivation, there are only around 60 cultivars to choose from, with only half of them available for home gardeners.
Apart from their amazing colors and fragrance, another nice quality of hyacinths is that it can be planted outdoors as well as indoors. This is a perennial bulb and can give the gardener an amazing vista as well as a superb lingering fragrance all through the spring.
Today’s hyacinths are some of the easiest to grow spring bulbs. They are even easy to plant or force in containers.
Being a perennial plant, hyacinth keeps blooming if given proper care. However, in a year they bloom only once i.e. in the spring. However, unfortunately, hyacinths are short-lived and tend to last only 3 to 4 years. Several growers treat them as tender perennials and tend to replace them yearly because of decline.
Unfortunately, flower quality usually declines after the initial planting year. The reason for this is that the fertile conditions under which the fresh bulbs are grown and post-harvest treatment induce dense spikes of large blooms. These factors decline in the following years.
Therefore, many gardeners consider this plant as a tender perennial and don’t expect more than 2-3 years of robust blooms.
Commercial growers produce accurately controlled, fertile environment and a specialized post-harvest heat treatment that produce dense spikes of gorgeous flowers. This is typically beyond the capability of home gardeners and doesn’t occur even in nature.
Therefore, to get constantly gorgeous blooms year after year, it’s best to replace the bulbs every year. Or as even smaller blooms look nice, growers can just enjoy them or they can add a few new bulbs every fall to keep the display looking good.
Singles: These contain full heads of reflexed flowers on a thick stalk.
Doubles: These contain dense swirls of double-petaled flowers on a stout stalk.
Multifloras: Each bulb of this variety produces several flowering stalks. However, flowers are loosely arranged. This variety can be planted in single colors, two tones, or multicolored arrangements on borders, lawns or under trees, or in containers.
Miss Saigon: This has tightly-packed blooms. The color of the florets is an attractive deep purple-pink.
Blue Jacket: Bluish-purple florets
Carnegie: Pure white
Jan Bos: Fuchsia
Delft Blue: Soft blue
City of Haarlem: This is a Dutch heirloom cultivar. It was first introduced in 1898. It starts blooming in the mid-spring in a primrose yellow color and slowly turns into a beautiful ivory. It has a strong fragrance.
Pink Pearl: This is a superb show flower in pink color. The flowers are formed of tiny florets that curve back and merge together to form a lovely mass of color.
Muscari Armeniacum: Also known as ‘grape hyacinth’, Muscari Armeniacum actually is not a hyacinth variety. But it has beautiful, tiny, delicate flowers in cobalt-blue color that resemble hyacinths. These look superb when planted in groups. Growers can plant these in similar ways as that of hyacinths.
What does “Forcing a Hyacinth” Mean?
Forcing a hyacinth means to pot the hyacinth bulbs in soil or place them in hyacinth glasses in water, replicate winter conditions and cause them to bloom earlier than their normal spring blooming time. The grower can force a hyacinth to bloom earlier, but after that, they cannot force it to bloom later in the year.
For forcing hyacinths at Christmas time or just after that, growers can even buy specially prepared bulbs. These are specially treated with heat so as to initiate an earlier display. These are a little more expensive.
Note: What is a hyacinth glass?
The Dutch invented specially-made glasses or glass vases for forcing hyacinth bulbs. These look like hour-glasses. Hyacinth glasses had become common by the mid-18th century. In a hyacinth glass bulb vase, hyacinth bulbs can be grown without soil.
When to Plant?
Hyacinths should be ideally planted in the fall 6 to 8 weeks before the first fall frost and they will bloom in the spring i.e. in March and April.
Growers should plant specially treated bulbs in September if they want the blooms for Christmas display since they need 10-12 weeks for proper root and shoot development.
Choosing the Planting Site
The site where the grower will plant hyacinths should be well-drained and should receive full sun or partial shade. Since, like all spring bulbs, hyacinths sprout, bloom, and start fading to dormancy before deciduous trees completely leaf out, growers don’t need to worry about too much shade from adjacent trees. Hyacinths are early bloomers that flower in late winter to early spring, depending on growers’ hardiness zone.
However, growers should note that full sun is more ideal for hyacinths if growers are going to keep them in one place (that receives full sun) for a few years. Partial shade is fine for a one-off display as they will bloom less well in the consecutive years if left there.
Soil should be loose, well-drained, and moderately fertile and its pH should be from 6 to 7. Hyacinths don’t like wet soils.
Before planting hyacinth bulbs, the grower should loosen the soil and add compost or bonemeal to it for fertility. However, too rich soil can cause floppy stalks; so, growers should be careful about organic matter while amending the soil.
Humidity and Temperature
Hyacinths normally survive in winter in USDA hardiness zones 4 to 8. In zones lower than 4, they may need some winter protection, and in zones above 8, they may need some pre-chilling, depending on the variety.
If the temperature is above 60°F, growers should dig out the bulbs and chill them for 6 to 10 weeks.
It’s a good idea to toss some bulb food in the planting hole right at the planting time. Several bulb foods are available or growers can even use an ordinary bone meal.
Growers should feed the bulbs while planting and again in the spring when new growth starts appearing, by scraping some fertilizer into the adjacent soil and watering well. They can use a slow-release bulb fertilizer with a 5-10-5 formula.
Mixing Up with Other Plants
If grown in large blocks, hyacinths develop the farthest-reaching fragrance. Hyacinths also blend well with any other spring-blooming bulbs as they have so many colors and sizes.
Being spiky, their flower stalks go well with ruffled daffodils and cup-shaped tulips. Growers can even choose the smaller Roman (sometimes referred to as French) and Multiflora cultivars to plant along walkways or in woodland settings.
Hyacinth bulbs should be planted 4 inches deep and at least 3 inches apart from each other. The northern limit of hyacinth’s hardiness is USDA Zone 4 and here they should be planted 6 to 8 inches deep.
Growers should remember to plant the bulbs with their pointy ends up.
Then they should cover the bulb completely with soil and water thoroughly. If grower is transplanting, they should water thinly and then should not water again till flower buds start showing the following year.
Note: Hyacinth bulbs (and daffodil bulbs) contain a compound known as oxalic acid which can cause itching to bare skin. Therefore growers should use gloves while working with these bulbs for prolonged periods.
How to Grow Hyacinths in Containers?
Growers should select containers with drainage holes for planting hyacinth bulbs. However, if there are no drainage holes in the container, they can use bulb fiber as it’s designed to hold water but doesn’t get too soggy. They can use any peat-free multipurpose potting compost to plant the bulbs or can prepare their own mixture by mixing two parts of compost and one part of perlite or grit as it will improve drainage.
There are two ways growers can grow hyacinths in containers:
1. They can grow multiple (minimum 3 to 5) bulbs in a container to achieve bright displays. They should plant bulbs 4 inches (10cm) deep and around 3 inches (7.5cm) apart. They should keep the container on ‘pot feet’ or bricks to improve drainage. To protect the container from frost damage in winter, they should wrap them in bubble wraps.
2. Alternatively, growers can plant bulbs individually in 3 ½ inch (9cm) pots for growing in a sheltered spot like a cold frame. Then in the spring, they can select the ones about to bloom at the same time and pot them up together to enjoy beautiful displays indoors.
After the bulbs bloom indoors, growers can move the containers to a sheltered place in the garden and feed them to induce blooming next year. Or they can even dig them out and plant them in a sunny spot in the garden.
Forcing Hyacinth Bulbs Indoors
As mentioned earlier, growers can grow hyacinths indoors too. For this, growers should use containers with drainage holes and fill them with soil-based potting mix, and plant the bulbs. They can even try a mixture of coconut coir, 1 part of sand, 1 part of compost, and a dash of bone meal. Peat-free coconut coir pellets are also available which growers can try. For containers without drainage holes, growers should use bulb fiber.
Before blooming, hyacinth bulbs need a cooling period. Sometimes pre-cooled bulbs, ready for forcing, are available at garden stores.
However, if growers don’t find them, they should just store the bulbs in a cold frame, garage, outdoor shed, or other dark areas for 8 to 12 weeks at temperatures from 35°F to 45°F. However, the bulbs should not be exposed to freezing temperatures. If growers keep them in the fridge, they should not keep the bulbs near apples as apples produce ethylene gas that can cause the bulbs to rot.
After the bulbs are precooled, growers can force them to bloom in almost any planting medium including potting soil, gravel, and water, the above-mentioned coconut coir mixture, or even plain water.
They can use the above-mentioned hyacinth glasses or “forcing jars” which they can find at garden stores, florists, and hobby suppliers. If planted in soil or other potting mixture in containers, the bulbs should be planted 4 inches deep but closer together than ground plantings, i.e. 1 to 3 inches apart, but they should not touch each other.
Once growers plant the bulbs, they should keep the containers in a dark place and the temperature should be above freezing point, but not higher than 45° F (7° C). They should continue this for a minimum of 10 weeks in order to allow roots to develop.
Grower should increase light and temperature slowly when shoots are around 1 inch long. Also, when leaves emerge, they should sprinkle a slow-release bulb food or a fertilizer in a 5-10-5 formula.
While watering, the grower should take care not to wet the shoots or waterlogging the soil. They should keep the soil moist, but not wet.
Once flowers fade and foliage starts dying back, the frequency of watering should be reduced.
Once flowering is over, the grower should return the pot to a sheltered place in the garden. They should promptly remove spent flower heads; however, they should leave the foliage to die back on its own.
Once the leaves die back, growers should lift the bulbs and store them in a dry, dark, and cool spot until fall planting. They should do the same with potted hyacinths received as gifts during the spring.
In Hyacinth Glasses
A hyacinth glass looks like an hourglass. However, the upper part of the glass can also be modified into a straight shape which helps in maintaining neat foliage. Also, the lower part can be given a round shape.
But the main characteristic of this glass is a constricted middle part. While planting in a hyacinth glass, growers should place the bulb in the upper part of the glass and add water up to but not touching the bottom of the bulb as bulbs sitting in water may rot. For this reason, hyacinth glasses come in handy as they are shrunk at the waist and the bulbs can be placed in the upper part nicely just above the water level.
Some growers place pieces of charcoal in the water in the lower part of the glass to keep the water sweet and stop slime formation. But this is not essential.
After this, the grower should place the glass in a dark, cool spot (at around 50°F) like an unheated garage, a cool cellar, or a regular fridge until the root system is properly developed and growth at the top appears. While storing in a refrigerator, growers should not store the glasses at this stage along with fruits, especially apples, as ripening fruits release ethylene gas which can damage or kill the flowers.
Growers should keep the glasses and bulbs cool for ten weeks and should add water regularly, but keeping the water level always below but close to the base of the bulb.
When shoots become around 2 inches tall and the roots extend towards the bottom of the glass, growers should move the jars to an intermediate spot where there would be low light and slightly warmer temperatures. During the next 3-4 days, growers should move the jars gradually into a sunny window.
When flowers appear, growers should keep the plants in bright, but indirect light. For the longest blooming time, the temperatures should be from 60°F to 65°F. Growers should keep the glass moving a little every day so that the flowers don’t lean to one side in search of sunlight.
Hyacinths grown in water cannot be planted in an outdoor garden. Therefore growers should compost them once blooming is over. However, if the grower wishes, they can try planting the bulb in their outdoor garden to see what happens next year.
Growers can enjoy blooms over the winter holidays by planting a series of bulbs every two weeks from the beginning of September to mid-October.
Taking Care of Hyacinths
After the hyacinths finish flowering in late spring for the year, growers should cut back the stalks. However, they should let the leaves die back naturally. The plants need the leaves to collect energy to bloom the next year.
Growers should not water hyacinth plants too often because hyacinth bulbs don’t like to have their feet wet. Too much watering can cause bulb rot.
But if the autumn is dry, growers should water hyacinths occasionally. If there is no regular rain, the grower should continue watering into winter. However, they should let the ground dry out between watering. If the bulbs are made to sit in wet, cool soil, they will rot.
Growers should remember to move their hyacinths to a sheltered spot or keep them covered with something like a bubble wrap to protect them from excessive winter moisture and frost damage. As the bulbs start swelling in a sheltered location over winter, growers should remove the cover and move bulbs to a sunny spot, either outdoors or indoors on a cool windowsill.
Some varieties of hyacinths are taller and may flop. Growers should stake them if they have only a few. Otherwise, they can plant them closer together so that they can support each other.
If growers want to propagate more hyacinth bulbs, they should wait until late summer. While propagating, they should lift the bulbs gently and remove the small offsets (baby bulbs) formed around the edges of the bulbs and then replant everything including the original bulbs. However, they should be patient as the offsets will take a few (3 to 4) years to bloom.
Propagation by Scooping
- Once the leaves die down, growers should lift the bulbs. They should only select large, healthy bulbs for propagation. They should remove the soil from the bulbs.
- For scooping, growers should scoop out all of the basal plate of a healthy dormant bulb with a sterilized, sharp scalpel or teaspoon. They should keep the outer rim intact.
- Then they should place the scooped bulbs, with their base upwards, on a layer of coarse but moist sand in a dark, warm place, such as an airing cupboard.
- Growers should regularly keep checking the bulbs for diseases and they should keep the sand moist.
- In due course (after around 3 months), the scooped section will develop bulblets.
- Growers should plant the mother bulbs (with bulblets attached) in late fall outside in a free bed and spread a 2-3 inch (5-7.5cm) thick layer of soil over them.
- Then in early summer, when the foliage of the mother bulb dies down, growers should carefully lift the new bulbs which will by then be the size of peas or small marbles (the mother bulb will be rotten away by then). Growers should line the new bulbs in beds. They should lift and replant them each year until they attain full size.
Harvest and Storage
If the grower has planted hyacinths outdoors, once the plants finish flowering, the grower should snip off the flower stalks. However, the foliage should not be removed because leaves gather the energy necessary for the bulbs to bloom the next year. The leaves will die back naturally at the end of the spring season and then the grower can remove them.
In most hardiness zones, hyacinth bulbs can remain in the ground all through the year. If the winter temperature in the grower’s area doesn’t get below 60° F (16° C), the grower should dig up the bulbs in the fall and refrigerate them for 6 to 8 weeks. Hyacinths need a colder climate to bloom.
If the grower has planted hyacinths indoors, once they finish flowering, the grower can transplant them to the garden. After blooming, the plants need time to gather energy to bloom the next year. Therefore, they should not place the plants directly into storage.
Once the leaves die back naturally outdoors, the grower can bring the hyacinth bulbs indoors and store them in a cool, dry, and dark place until the fall or winter.
Taking Care of Hyacinths After Flowering
Once the leaves die back, growers should lift the bulbs and store them in a dry, dark and cool spot until fall planting. After the bulbs are dug out, the grower should brush clean the soil from them and trim the roots and the loose, papery outer layer called “tunic”. Growers should keep only larger-sized healthy bulbs and discard damaged or diseased ones.
To prevent fungal rot in storage, growers should lay the bulbs on drying racks or trays for 24-48 hours to air dry. Then they should place the bulbs in mesh nets or paper bags and store them in a dry, dark and cool spot until replanting again in the fall.
However, if the bulbs are naturalized in grassy areas or under deciduous trees and shrubs, or if they have permanent homes in planters or beds, growers should leave them there.
Hyacinths are hardy to growing zones 4 to 8 and can remain in the ground all through the year in these zones. In areas with severe winter temperatures or harsh spring frosts, growers should apply a 2- to 4-inch thick layer of mulch until the risk of frost passes.
Pests and Diseases
Some diseases that can occur prominently in hyacinths are:
If growers water the plant too frequently, the excess water can cause a bulb rot.
Gray mold can occur in hyacinth bulbs.
This is a fungal disease that can occur if the soil temperature is around 65°-75°F. It causes leaves and roots to stunt and the bottom of the bulb to rot.
Growers should discard diseased bulbs. They should apply a fungicide to bulbs before planting. They should not replant a similar variety in the same spot for a minimum of 3 years if basal rot has occurred.
In late spring frosts, leaves and stems can be damaged with brown spots and blotches or split edges. To avoid frost damage, growers should apply a 2-4 inch thick layer of mulch over the bulbs after the ground freezes.
Pests include all types of rodents like chipmunks, groundhogs, voles, and squirrels, and skunks too, which like to munch on hyacinth bulbs. Growers should throw a handful of gravel in the planting hole or can try commercial rodent deterrents. A still easier way is to alternate hyacinths with daffodils which rodents normally avoid. Bulbs can also be protected from rodents with wire mesh.
Problem of Flowers Failing to Emerge
Sometimes growers growing hyacinths indoors may face a problem of their flowers not emerging from the leaves before flowers open. This happens if the room is too warm. This problem can be resolved by moving the container to a cooler room until the flower stalk becomes taller than the leaves. If growers find that the flower stalk is too weak to stand upright, it means that this room too is too warm and therefore they should move the container to a still cooler room.
Word of Caution
Growers should remember that hyacinth bulbs are toxic to pets. Several spring flowers, including hyacinths and daffodils, have a substance called calcium oxalate in them that can cause respiratory and stomach issues, and also skin irritation. Hyacinth bulbs have a maximum concentration of this compound, but leaves and flowers have it, too.
Hence, growers should keep hyacinths out of reach of pets and children. They should also wear gloves while handling the bulbs.
Growing hyacinths can be truly rewarding and hence every gardener should grow them and enjoy the rainbow of colors and amazing fragrance.