Eazy Gardening

Jubilee Gem: The Stunning Blue Cornflower for Every Garden

Centaurea cyanus, also known as the cornflower, is a captivating wildflower that has been cultivated for its beauty and medicinal properties for centuries. One particular variety, Jubilee Gem, is known for its stunning blue color and compact size.

In this article, we will take a closer look at Jubilee Gem and its characteristics, as well as explore tips for cultivating and caring for this lovely plant.

1) Overview of the plant

Common Names and Vernacular Names

Centaurea cyanus is commonly known as the cornflower, bachelor’s button, bluebottle, and thimbles. The name bachelor’s button is derived from the tradition of wearing the flower in the buttonhole of young men to declare their single status.

Bluebottle and thimbles refer to the shape of the flower, which resembles a small bottle or thimble.

Description of the Plant

Jubilee Gem is a compact and dwarf variety of Centaurea cyanus that grows to around 12-16 inches tall. The flowers are small, typically measuring around 1-2 inches in diameter, and are a stunning electric blue color.

The leaves are narrow and lance-shaped, with a gray-green hue. Jubilee Gem blooms in mid-summer and continues to bloom well into the fall, making it a popular choice for cut flower arrangements.


Centaurea cyanus, including Jubilee Gem, is an excellent addition to any garden or landscape. Its stunning blue color adds a pop of vibrancy and life to any space.

Additionally, the flowers are incredibly beneficial to wildlife, particularly bees and butterflies. The nectar and pollen from the flowers provide an essential food source for these pollinators, helping to support and maintain their populations.

2) Plant Cultivation and Care

Preferred Growing Conditions

Jubilee Gem thrives in full sun and well-draining soil. It can grow in a wide range of soil types, but prefers soils that are rich in organic matter.

This plant is also highly tolerant of drought, making it ideal for regions with low rainfall or in areas where water is scarce.

Potential Pest and Disease Issues

One of the most significant threats to Jubilee Gem is powdery mildew, a fungal disease that spreads easily in humid or damp conditions. To prevent this disease, ensure that the plant is grown in a well-ventilated area, with plenty of air circulation.

Other pests, such as aphids and spider mites, can also infest this plant. These pests can be controlled by spraying the plant with insecticidal soap or neem oil.

Planting and Maintenance Tips

Plant Jubilee Gem in early spring or late fall, when the soil is still cool, to give the plant the best chance of establishing roots before the hot summer months. Water regularly during the first few weeks after planting to help the plant establish, but reduce watering once the plant is established.

Jubilee Gem does not require frequent fertilization; however, a slow-release fertilizer can be added to the soil in early spring to promote healthy growth.


Centaurea cyanus ‘Jubilee Gem’ is a beautiful and well-loved variety of the cornflower. Its compact size and electric blue flowers make it an excellent addition to any garden or landscape.

By following these simple cultivation and care tips, you can ensure that your Jubilee Gem plant is healthy and thriving. Enjoy the beauty of this stunning flower and support the vital work of pollinators!

3) Plant Propagation Methods, Including Sexual and

Asexual Reproduction

Like many other plants, Centaurea cyanus ‘Jubilee Gem’ can be propagated through both sexual and asexual reproduction.

Sexual reproduction involves the use of seeds, while asexual propagation involves the use of vegetative means.

Sexual Reproduction

Jubilee Gem produces seeds after blooming. To harvest the seeds, allow the flowers to dry on the plant, then cut them off and hang them in a dry, well-ventilated area to finish drying.

Once the seeds have dried, they can be stored in an airtight container until it is time to plant them. To grow Jubilee Gem from seeds, plant them in well-draining soil in either the spring or fall.

Sow the seeds at a depth of around 1/4 inch and water them thoroughly. Keep the soil evenly moist until the seedlings emerge, then reduce watering to encourage the seedlings to develop a strong root system.

Seedlings can be transplanted into their permanent location once they are around 2-3 inches tall.

Asexual Reproduction

Asexual propagation of Jubilee Gem can be done through methods such as division and stem cuttings. Division involves dividing the parent plant into smaller sections, while stem cuttings involve taking a cutting of a stem and using it to grow a new plant.

To divide a Jubilee Gem plant, dig up the parent plant and carefully separate the roots into smaller sections. Each section should have its own set of leaves and a root system.

Replant each section in well-draining soil, water thoroughly, and keep the soil evenly moist until the plants establish themselves. Stem cuttings should be taken in the spring or summer, when the plant is actively growing.

Select a healthy stem and cut a 4-6 inch section from it, making sure there are at least two sets of leaves on the stem. Remove the lower leaves and any flowers or buds, then dip the cut end of the stem in rooting hormone powder.

Plant the stem in well-draining soil, water thoroughly, and keep the soil moist until the cutting develops roots.

4) Plant Adaptations to Different Environments

Centaurea cyanus ‘Jubilee Gem’ has adapted to grow in a wide range of environments, from dry and arid to moist and humid. These adaptations allow the plant to thrive in diverse locations and conditions.

One of the key adaptations of Jubilee Gem is its tolerance of drought. This plant is well-suited to grow in dry, arid regions and can survive with minimal water.

Its deep root system allows it to access moisture from deep within the soil, which helps it to survive even during long periods of dry weather. Another adaptation of Jubilee Gem is its preference for full sun.

This plant requires a minimum of six hours of sunlight per day to thrive and will not grow well in shady areas. The leaves of the plant are adapted to absorb the maximum amount of sunlight possible, helping it to produce the energy it needs for growth and blooming.

Jubilee Gem is also highly adaptable to different soil types. It can grow in a wide range of soil types, from sandy to loamy to heavy clay.

Its root system is designed to be able to penetrate a variety of soil types, allowing it to access nutrients and moisture even in less-than-ideal soils. Finally, Jubilee Gem has adapted to be beneficial to wildlife, particularly pollinators such as bees and butterflies.

The plant produces nectar and pollen that are essential food sources for these insects, which helps to support and maintain their populations. The flower structure of Jubilee Gem is also adapted to make it easy for pollinators to access the nectar and pollen, with a shallow disk surrounded by spiky bracts that help to guide the insect in.


Centaurea cyanus ‘Jubilee Gem’ is a remarkable plant that has adapted to thrive in a wide range of environments. Its ability to tolerate drought, preference for full sun, and adaptability to different soil types allow it to grow in diverse locations.

Additionally, its beneficial properties for pollinators make it an essential part of any garden or landscape. With the right cultivation and care, Jubilee Gem can thrive and bring beauty and life to any space.

5) Usage of the Plant in Indoor Settings

Centaurea cyanus ‘Jubilee Gem’ can also be used as an indoor plant. While it is primarily grown outdoors, it can be grown successfully indoors with proper care and attention.

Indoor Conditions

To grow Centaurea cyanus ‘Jubilee Gem’ successfully indoors, it is important to provide it with the right growing conditions. This plant thrives in bright light, which is essential for healthy growth, blooming, and foliage color.

It is highly recommended that the plant be placed near a south-facing window where it can receive at least 6 hours of direct sunlight each day. In low-light conditions, it can be supplemented with the use of artificial lighting such as fluorescent bulbs.

Soil and Watering

When planting Jubilee Gem in a container, be sure to use a well-draining soil mix, preferably one with a high percentage of perlite or sand to ensure adequate drainage. Water the plant when the top inch of soil is dry to the touch, taking care not to allow the soil to become waterlogged.

Fertilization and Maintenance

Jubilee Gem doesn’t require frequent fertilization, but it can benefit from the occasional application of a balanced, slow-release fertilizer to promote healthy growth. It is also important to monitor the plant for pests and disease, as indoor plants are more susceptible to infestations.

6) Usage of the Plant in Outdoor Settings

Centaurea cyanus ‘Jubilee Gem’ is primarily grown outdoors and can be used in a variety of settings to enhance the beauty of any landscape or garden.

Garden Decoration

Jubilee Gem is an ideal plant for garden borders, rock gardens, and container gardens. Its compact size and bright blue blooms make it a perfect addition to mixed flower beds or as a standalone plant.

In addition, it blooms late in the summer, making it ideal for adding interest to fall gardens and landscapes.

Wildlife Gardens

Jubilee Gem is highly beneficial to pollinators such as bees and butterflies, making it an excellent choice for wildlife gardens. By planting this flower, you provide a source of food and habitat for these essential insects, helping to support and maintain their populations.

Cut Flowers

The bright blue flowers of Jubilee Gem make it a popular choice for cut flowers. Cut flowers can be used to create stunning floral arrangements that last for up to a week.

The flowers should be cut when they are fully open and just starting to fade; this way, they will last longer in the vase.

Dried Flowers

Jubilee Gem flowers can also be dried and used in a variety of DIY projects, such as floral wreaths and potpourri. To dry the flowers, cut them when they are fully open and hang them upside down in a dry, cool, and dark area for several weeks until they are completely dry.

Once they are dry, store them in an airtight container until ready to use.

Edible Uses

Not commonly known, the flowers of Jubilee Gem can be used as a natural food coloring. They can also be used to flavor vinegar, desserts, and teas.

The flowers have a slightly sweet and spicy flavor.


Centaurea cyanus ‘Jubilee Gem’ is an incredibly versatile plant that can be used in a variety of settings. Whether grown indoors or outdoors, this plant will add a pop of vibrant blue color while also benefiting pollinators and other wildlife.

Additionally, it can be used to produce cut flowers, dried flowers, or as a natural source of food coloring. With the proper placement and care, Jubilee Gem is sure to bring beauty and life to any space.

7) Toxicity of the Plant to Pets and Horses, Humans

While Centaurea cyanus ‘Jubilee Gem’ has many benefits for wildlife and humans, it is important to note that parts of the plant can be toxic to pets and horses if ingested in large quantities. Jubilee Gem contains chemicals that can cause gastrointestinal discomfort or allergic reactions in some animals and humans.

Toxicity in Pets and Horses

Jubilee Gem contains a compound known as pyrrolizidine alkaloids that are potentially toxic to pets and horses if ingested in large quantities. Ingestion can cause liver damage, diarrhea, colic, and other gastrointestinal issues, as well as kidney failure in severe cases.

Symptoms generally appear 1-2 weeks after ingestion, though it may take longer in some animals.

Toxicity in Humans

While Jubilee Gem is not generally considered toxic to humans, it does contain pyrrolizidine alkaloids, which can cause liver damage if ingested in large quantities over an extended period of time. Symptoms of pyrrolizidine alkaloid toxicity in humans may include nausea, vomiting, abdominal pain, and jaundice.

Preventing Ingestion

To prevent ingestion of Jubilee Gem by pets and horses, it is important to keep them away from the plant and remove it from grazing areas if necessary. If you suspect your animal has ingested Centaurea cyanus ‘Jubilee Gem’, call your veterinarian immediately.

Furthermore, avoid using the plant parts in recipes if planning to consume them.


While Centaurea cyanus ‘Jubilee Gem’ is an attractive and useful plant, it is also important to take precautions to prevent ingestion by pets and horses. By understanding the risks associated with consuming this plant, you can take steps to protect your animals.

As always, consult your veterinarian if you suspect your pet or horse has ingested a toxic plant. In conclusion, Centaurea cyanus ‘Jubilee Gem’ is an adaptable, low-maintenance plant that is beneficial to both wildlife and humans.

With the right growing conditions and care, it can thrive both indoors and outdoors, providing vibrant blue blooms and a range of uses, such as cut flowers, dried flowers, and natural food coloring. While it is toxic to pets and horses in large quantities, avoiding ingestion is easy with proper precautions.

Overall, Jubilee Gem is a beautiful and versatile addition to any landscape or garden that provides numerous benefits for both ourselves and nature. FAQs:


Is Centaurea cyanus ‘Jubilee Gem’ toxic to humans? While Centaurea cyanus ‘Jubilee Gem’ is not generally considered toxic to humans, it does contain pyrrolizidine alkaloids that can cause liver damage if ingested in large quantities over an extended period of time.

2. Can Centaurea cyanus ‘Jubilee Gem’ be grown indoors?

Yes, it can be grown indoors with proper sunlight exposure and well-draining soil. 3.

Is Centaurea cyanus ‘Jubilee Gem’ drought-tolerant? Yes, it is highly tolerant of drought and can survive with minimal water.

4. Can I grow Centaurea cyanus ‘Jubilee Gem’ from stem cuttings?

Yes, Jubilee Gem can be propagated from stem cuttings, which should be taken in the spring or summer when the plant is actively growing. 5.

Are the flowers of Centaurea cyanus ‘Jubilee Gem’ edible? Yes, the flowers can be used as a natural food coloring and can also be used to flavor vinegar, desserts, and teas.

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