It is natural to assume that all plants develop in the same way. That each plant has the same fleshy underground storage structure at the point where the root system meets the base of the stem. This storage structure is known as a bulb, and while many plants do develop a distinct storage system not all plants do. Additionally not all storage systems are the same.
As well as explaining what a bulb is, and why it is so important to the life cycle of some plants, this article will also highlight some of the most commonly grown bulb flower types.
There are many different bulb flower types.
- 1 What is a Bulb?
- 2 True Bulbs
- 3 Corms
- 4 Tubers
- 5 Tuberous Roots
- 6 Rhizomes
What is a Bulb?
A bulb is a plant with an underground storage structure. This storage structure enables the plant to not only bloom but to complete its entire life cycle. The storage system also contains all the nutrients and moisture that the plant should need. If the storage system is removed or damaged the plant will not survive.
Most bulb flower types are perennials, as long as they are planted in the correct USDA Zone. While the different bulb flower types can all flourish at different times of the year and for different lengths of time, the life cycle is largely the same. After a sustained period of growth, blooms emerge. As these fade, marking the end of the growing season, the foliage continues to store energy before yellowing and dying back to ground level. At this point, the plant enters a period of dormancy. Once dormancy has ended the life cycle begins again.
For example, spring blooming bulb flower types set bud in the spring. During the summer months the blooms fade but the foliage remains in place, harvesting enough light and moisture, which the plant converts into energy and stores, to survive the winter months. Once the plant has stored as much energy as it can, it enters a dormant period, typically during the fall or winter months. As winter fades and spring returns, the plant re-awakens, sending up shoots and starting the cycle all over again.
There are five main bulb flower types. While they all operate in largely the same way, for example they all have a form of storage structure, each of the bulb flower types has some key differences. During the course of the article we will explore these differences as well as highlighting some of the most commonly grown plants of each of the different bulb flower types.
The five main bulb flower types are:
- True bulbs,
- Tuberous roots,
True bulb flower types have five main sections:
- Basal plate, from which roots emerge.
- Fleshy scales, this is where the storage tissue develops.
- Tunic, a skin-like covering which protects the storage tissue.
- Shoot, this comprises the leaf buds as well as the developing floral bud or buds.
- Lateral buds which develop into offsets. Once separated from the main storage system they can be planted on and grown as new plants.
This category can be further split into two distinct groups: tunicate and imbricate.
Tunicate bulb flower types have a tunic or skin that feels like paper. The purpose of this papery layer is to protect the scales from injury. The tunicate enables the plant’s storage system to be safely handled. This protection also enables you to use them in areas dedicated to cultivating cut flowers.
Imbricate bulb flower types do not have a protective tunic. This means that they require more careful handling than tunicate bulb flower types.
Hyacinths are one of the most popular tunicate bulb flower types thanks to their vibrantly colored blooms. Native to the Mediterranean, Hyacinth blooms develop in clusters on the stalk. A popular ornamental plant, Hyacinths are commonly grown as houseplants. If you want to try something a little different, you can also grow Hyacinths in water.
A popular houseplant, some people like to leave the top of the Hyacinth’s storage system exposed.
Spring blooming perennials, Tulips are bulbiferous plants, popular for their large, colorful showy spring blooms. Popular in mixed beds, containers and floral displays, Tulips come in a range of colors including white, yellow and red.
Native to many parts of Europe as well as central Asia, today Tulips are naturalized in a number of countries around the world. Despite its delicate appearance, the shoot of the Tulip’s tunicate bulb securely holds one large bloom.
Blooming in the spring before slowly dying back, Tulips are a reliable way to add color and height to spring beds.
Tulips are one of the easiest bulb flower types to grow.
Another bulbous perennial, there are many different cultivars grouped under the Muscari genus.
Native to Eurasia, Muscari plants are identified by their dense, blue urn-shaped blooms. When fully open the blooms cover the stem, resembling a bunch of grapes. Hence the common name Grape Hyacinths. Despite the name, and while they are both tunicates, Muscari plants are not related to Hyacinth bulb flower types. Muscari is a popular inclusion in rock gardens, the plants can also be grown as houseplants.
The densely packed Muscari blooms.
Like Tulips, Daffodils are spring blooming, tunicate bulb flower types. A member of the Narcissus genus, the Daffodil is a spring perennial in the Amaryllis family. Typically yellow in color, you can also find white or orange varieties.
Daffodils are identified by their distinctive trumpet or cup shaped blooms which have 6 petals. Naturalized throughout the world, Daffodils are native to southern Europe, North Africa and the western Mediterranean. They are a popular inclusion in mixed beds and borders. Despite their delicate appearance, Daffodil’s are surprisingly resilient plants which are easy to cultivate, as our growing guide shows.
The protective skin of the Daffodil is clearly visible.
The Allium genus is one of the most common tunicate bulb flower types in the garden. Onions, Scallions, Leeks, Chives and Garlic all belong to the Allium family. Alliums is also the name given to attractive ornamental plants. These add height and long lasting color to containers and mixed beds. Easy to grow, Alliums can be found in many parts of the northern Hemisphere; some cultivars are also native to Chile, Brazil and parts of tropical Africa.
Adding height and structure to mixed planting schemes, like many members of the Allium family, Alliums are a reliable companion plant.
Belonging to the same family, Alliums can resemble onions.
One of the few herbs on our list of bulb flower types, Scilla is a perennial herb that thrives in coastal areas as well as meadows and woodlands. Native to Europe, Africa and the Middle East, Scilla is also naturalized in parts of North America, New Zealand and Australia.
Belonging to the same family as Hyacinth plants, during the spring pink, blue and white blooms emerge. Some varieties can be encouraged to bloom in the fall, adding late season color to the garden.
Be careful when handling Scilla plants, they are poisonous. Wear gloves and a long shirt to protect your hands from potential skin irritation.
Lilies are imbricate bulb flower types. Available in a myriad of attractive varieties, the Lily is a herbaceous plant, popular for its large, fragrant blooms.
Many types, such as the Calla Lily, are grown specifically for their appearance. Native to temperate parts of the Northern Hemisphere many Lily plants aren’t true lilies.
The Asiatic Lily is a particularly elegant cultivar. Stately and elegant, with long lasting, colorful blooms, in cooler climates the plants are best grown in containers. This makes protecting them from cold winter temperatures a lot easier.
Floral spikes and foliage emerge from the top of the storage system.
Corm bulb flower types have a noticeable swollen area at the base of the stem. This is the area where the storage tissue lives. Unlike True Bulbs which have visible storage rings when cut in half (think about slicing an onion in half) Corms have no visible storage rings. Corm roots typically develop from the basal plate. Thin tunics are often present, protecting the storage system’s scales.
Perennial plants that are sometimes called Sword Lilies, Gladiolus are attractive ornamentals. Native to Mediterranean Europe, tropical Africa, South Africa and Asia, in cooler regions Gladiolus corms have to be dug up and stored in the fall, once the growing season has ended. This helps to protect them from the harsh winter weather.
After lifting your Gladiolus plant, the corms can be separated and replanted the following spring. Typically pea-sized, any corms that are poorly formed, underdeveloped or visibly diseased should be discarded. Separating the corms is not only a great source of free plants, it also helps to keep many bulb flower types of plants healthy and productive.
Round Gladiolus corms.
One of the more popular blooming bulb flower types, the Crocus, is a popular choice in meadows, mixed beds and woodland planting schemes. An early sign of spring, alongside Tulips, Daffodils and Snowdrops, the Crocus is also a reliable bedding plant.
Native to Southern and Central Europe, the Middle East, North Africa and Central Asia the Crocus is one of the most reliable bulb flower types.
Equally attractive, the Saffron plant, from which we get the herb is the product of the stigma of the Crocus sativus plant.
Crocus plants emerging from the ground are one of the earliest signs of spring.
Another one of our herbaceous, perennial bulb flower types, bright and colorful Freesias are native to parts of Africa. Popular for their fragrant, funnel-shaped blooms, today a number of hybrid varieties are available. This has only helped to increase the popularity of these attractive, ornamental plants. Like many plants, Freesias can be planted in container gardens or grown as houseplants. Easy to cultivate, Freesias look particularly effective if planted in a group.
Fragrant Freesia blooms.
Unlike other bulb flower types, Tubers do not have a basal plate. The basal plate is the section from which roots usually emerge. Tubers also do not have a protective tunic. As they develop, Tubers tend to scatter buds. From these buds the roots develop. The buds can also send shoots upwards out of the ground.
Like other bulb flower types, Tubers have a storage organ which needs to gather and store enough nutrients during the spring, summer and fall to survive the dry winter months and enable fresh growth to emerge the following year.
A popular part of the vegetable garden, potatoes are one of the most commonly grown root vegetables. As the stem of the Potato develops above ground, producing foliage and blooms, below ground small buds develop on the root system. These eventually develop into potatoes, sometimes known as tubers.
Easy to grow in fresh soil or planters, in many areas Potatoes also grow in the wild. If you are short on space you can also grow Potatoes in containers.
One of the most reliable plants in the vegetable garden, Potatoes are a low maintenance, resilient crop. Just make sure that your soil is healthy. These versatile plants can also be used to provide ground cover in certain situations.
Potatoes form on the root system of the plant.
A member of the Ranunculaceae family, Anemones are attractive, ornamental plants popular for their spring blooms. The poppy anemone is a particularly attractive variety thanks to its parsley-like foliage and large, showy blooms.
Anemone tubers do best in loamy soil. To encourage healthy growth and lots of large blooms, work in enrichments such as well-rotted manure before planting. Easy to grow and pleasingly hardy, Anemones are a great choice for novice or nervous gardeners. They are also a popular inclusion in cut plant gardens and displays.
The large open blooms of the anemone are a popular inclusion in mixed beds and borders.
Caladium plants are members of the Araceae family. Often called Elephant Ear, Heart of Jesus or Angel Wings, Caladiums are native to Central and South America. Today the plants are also naturalized in some parts of India and Africa. In the wild they can often be found growing along river banks.
Thriving in shady areas, where the tropical looking foliage adds interest, during dry spells Caladium plants can become dormant. A Sunblock Shade is an easy way to shade sensitive plants in bright, sunny gardens, protecting them from burning or wilting. In ideal conditions Caladiums may sometimes bloom.
Caladium’s tuber root.
Bulb flower types with Tuberous Roots can be identified by their root structure. This is visibly different to the storage system of other plants. Plants with Tuberous Roots store nutrients in the root rather than in a swollen or enlarged stem section. These bulb flower types commonly have fleshy or enlarged root tissue.
Small tubers, which can be separated from the larger, mature Tuberous Root, typically form at the crown, or the top of the root system.
Another of the herbaceous perennial bulb flower types on our list, there are numerous different types of Dahlias. Despite their differences, each Dahlia variety produces only one bloom, in a range of colors, including pink, yellow and red, on each stem. The tuberous roots of the Dahlia reproduce from buds which form at the top of the root, at the point where it meets the stem.
Native to Mexico, where it is the national plant, the Aztecs grew Dahlias as food, the tuberous root is edible. Dahlias have to be dug up in the fall for winter storage. When storing your Dahlias, be careful not to damage the tuberous roots. Unlike other bulb flower types you should not divide tuberous roots at the point of lifting. Instead divide in the spring, when re-planting. Each divided section should have an eye bearing portion, it is from this that the plant develops.
15 Sweet Potato
Popular in the southern states, the Sweet Potatoes’ large, starchy tuberous roots are surprisingly easy to cultivate, making them a valuable addition to the vegetable garden.
Sweet Potatoes are members of the same family, convolvulaceae family as Morning Glory. As well as the roots, Sweet Potato shoots and foliage are also edible. Also known as Yams, botanically Sweet Potatoes differ from Yams. A true Yam is a perennial plant with a long, tapered root. The tuberous root of the Sweet Potato has a smooth skin which can be yellow, brown, red or orange.
Sweet potatoes are popular for their starchy, tuberous roots.
Cassava or Manihot esculenta is native to South America where it is typically cultivated as an annual plant. The starchy, tuberous roots have a nutty, bittersweet taste and are a staple of many dishes. The roots can also be grated to make edible coarse flour, Brazilian Farinha.
Thriving in tropical climates, Cassava plants require an extended period of warm weather in order to thrive. Best planted in well draining soil and full sun, Cassava plants tend to struggle in cold conditions.
Cassava roots are popular for their bittersweet flavor.
A popular bedding plant, the tuberous roots of the Begonia differ from other flowering plants. Happiest in cool conditions and high humidity, Begonias struggle in hot, arid environments.
There are many different cultivars of Begonia that are commonly grown in gardens and as houseplants. Many of these are popular for their colorful, long lasting blooms and interesting, variegated foliage. A tender perennial, many cultivars such as Rex Begonias are also grown as houseplants.
Colorful Begonias thrive in cool conditions.
Our final category of different bulb flower types, the name Rhizome is derived from the Ancient Greek ‘rhizoma’, meaning a mass of roots. Compared to other bulb flower types, Rhizomes have unique storage structures. This gives them an often knobbly appearance.
Rhizomes are sometimes called creeping rootstalk due to the unusual way that the roots spread. Unlike other bulb flower types that send roots vertically down into the soil, most Rhizome roots tend to spread horizontally below soil level. Many types of Rhizome have a strong growth habit. Some varieties are considered invasive.
Ginger is one of the most popular rhizomes. Commonly used as a spice or herbal remedy, the Ginger plant is a herbaceous perennial. Native to southeast Asia, Ginger was one of the first spices exported from Asia to Europe in the spice trade.
Surprisingly easy to grow, particularly in warm climates. Growers in cooler areas will have more success cultivating their ginger plants undercover in a greenhouse.When grown for its ornamental value, Ginger’s knobbly rhizomes send up flowering stalks adorned with pale yellow and purple blooms.
Knobly Ginger rhizomes have a range of uses.
A member of the Zingiberaceae ginger family, Turmeric root is used in cooking and herbal remedies. Native to Southeast Asia and the Indian subcontinent, Turmeric is a tropical plant. Growing turmeric requires temperatures between 68 and 86 ℉ and regular water in order to survive. A moisture meter, such as the SONKIR Soil Moisture Meter provides an easy way to monitor the moisture content of your soil. It is a particularly useful gadget when cultivating plants that prefer damp conditions or if you are growing in a warm area, where the soil and plants may quickly dry out.
As well as being a beneficial superfood, Turmeric rhizomes can also be ground up as a dye
Commonly grown as a herb, Turmeric is also an attractive ornamental blooming plant.
20 Lily of the Valley
Popular for its distinctive sweet fragrance and bell-shaped white blooms, these spring flowering plants are native to cooler parts of the Northern Hemisphere. A staple of the ornamental garden, Lily of the Valley has a vigorous spreading habit. In some areas these attractive little plants are considered invasive.
A reliable perennial, in cooler climates Lily of the Valley can continue to bloom well into winter. For more on growing these delicate little plants, check out our growing guide.
Warning, Lily of the valley is poisonous. Keep the plants away from pets and small children and always wear gloves when handling.
Fragrant and attractive, Lily of the Valley has an intense spreading habit.
As you can see bulb flower types come in a range of shapes, sizes and habits. These differences are key to helping the different bulb flower types to develop and thrive, returning to your garden year after year.