Sea Holly Eryngium bourgatii 'Oxford Blue'
ABOUT
Eryngium bourgatii 'Oxford Blue', commonly known as sea holly, is a striking perennial that is prized for its distinctive appearance. This plant features a rosette of dark green, spiky leaves that create a dramatic texture in the garden. The foliage can exhibit a blue or silver tint, enhancing its ornamental appeal. Rising above the foliage are branching stems that bear cone-shaped flower heads surrounded by a ruff of spiny bracts. These bracts are usually a vibrant metallic blue or blue-purple color, which contrasts beautifully with the green leaves and can add a pop of color to the landscape. The intense color of the 'Oxford Blue' variety is particularly eye-catching, and the flowers attract a variety of pollinators, including bees and butterflies. The overall look of the sea holly is one of rugged beauty and architectural interest, with a touch of whimsy due to its spiny and somewhat thistle-like appearance.
About this plant
NamesFamily
Apiaceae
Synonyms
Mediterranean Sea Holly, Pyrenean Sea Holly, Oxford Blue Sea Holly
Common names
Eryngium bourgatii 'Oxford Blue'.
ToxicityTo humans
Sea holly is generally not considered toxic to humans. When handled or ingested in normal garden situations, it does not typically pose a risk of poisoning. Therefore, if sea holly is consumed by accident, there are usually no serious consequences or symptoms of poisoning associated with it.
To pets
Sea holly is not known to be toxic to pets. It is not listed among the common poisonous plants for animals such as cats and dogs, and ingestion should not cause any notable symptoms of poisoning. As with any non-food plant, ingestion of large quantities may cause gastrointestinal discomfort due to the physical nature of the plant material, but this is not specific to its toxicity.
CharacteristicsLife cycle
Perennials
Foliage type
Deciduous
Color of leaves
Green
Flower color
Blue
Height
2 feet (60 cm)
Spread
1 foot (30 cm)
Plant type
Herb
Hardiness zones
5
Native area
Pyrenees
Benefits
General Benefits- Aesthetic Appeal: 'Oxford Blue' Sea Holly, as it is commonly known, has striking blue flowers and silver-green foliage that add beauty to any garden.
- Drought Tolerant: This plant is extremely drought-resistant, requiring minimal water once established, making it a good choice for xeriscaping and water-conserving gardens.
- Low Maintenance: 'Oxford Blue' Sea Holly is easy to care for, needing little attention once it has been planted in suitable conditions.
- Pollinator Attraction: The vibrant flowers attract bees, butterflies, and other beneficial insects, supporting biodiversity.
- Deer and Rabbit Resistant: Its spiny leaves and tough nature make it less appealing to deer and rabbits, which can help protect other more vulnerable plants in your garden.
- Long Blooming Period: The long-lasting flowers bloom from early to late summer, providing extended visual interest in the landscape.
- Cut Flower: 'Oxford Blue' Sea Holly makes an excellent cut flower for bouquets and arrangements, adding unique texture and color.
- Dried Flower: It can be dried effectively, retaining its shape and color, and used in dried flower arrangements.
- Structural Interest: The distinctive geometric shape of its flower heads and foliage can add architectural interest to garden beds or borders.
- Versatile Garden Use: Suitable for rock gardens, coastal gardens, borders, and containers, providing flexibility in landscape design.
Medical PropertiesThis plant is not used for medical purposes.
Air-purifying QualitiesThis plant is not specifically known for air purifying qualities.
Other Uses- Eryngium bourgatii 'Oxford Blue', commonly known as Sea Holly, can be used in themed gardens such as rock or seaside gardens, where the plant's hardy nature and unique texture will complement the garden design.
- Sea Holly acts as an excellent dried flower for arrangements, maintaining its color and form for an extended period after drying.
- The striking blue to steel color and thistle-like appearance of Sea Holly make it a popular choice for gothic or darker themed floral decorations.
- Sea Holly can be incorporated into wildlife gardens, as it is known to attract bees and butterflies, contributing to local biodiversity by supporting pollinator populations.
- The plant's resilience to coastal conditions, including salt spray, makes it a suitable ornamental plant for coastal erosion control in home or community landscaping.
- Sea Holly has been traditionally used in artisanal crafts, such as being incorporated into wreaths and other decorative objects due to its structural properties.
- Its unique appearance allows Sea Holly to serve as a living barrier or edging in gardens, with its spiny leaves deterring pets and wildlife from trampling garden beds.
- The plant's distinctive shape and color can inspire artists and photographers, making it a subject for botanical illustration and plant photography.
- Because of its visually striking nature, Sea Holly can be used as a focal point in small space or container gardening, providing structure and color to balconies and patios.
- Sea Holly can be used for educational purposes in school gardens or educational programs, teaching children about plant structure, adaptation, and pollinator attraction.
Interesting Facts
Feng ShuiSea Holly is not used in Feng Shui practice.
Zodiac Sign CompitabilitySea Holly is not used in astrology practice.
Plant Symbolism- Determination: Sea Holly often thrives in hostile environments and poor soils, symbolizing the ability to persevere and succeed despite difficulties.
- Attraction: The striking blue color and unique form of Sea Holly's blooms can symbolize an irresistible pull or magnetism, possibly in a romantic context.
- Protection: With its spiky leaves and bracts, the Sea Holly can represent defense or protection against harm and adversity.
- Independence: Sea Holly's hardy and resilient nature may reflect a person's independent spirit and self-sufficiency.
WaterSea holly (Eryngium bourgatii 'Oxford Blue') prefers soil that is well-drained and not overly wet, so it's important to avoid overwatering. Allow the soil to dry out somewhat between waterings. During the growing season, water sea holly once every week or two, providing about one gallon of water per square yard of soil each time. It's more drought-tolerant once established and can survive longer periods without water. However, in very hot or dry conditions, check the plant more frequently to ensure the soil hasn’t dried out completely.
LightSea holly (Eryngium bourgatii 'Oxford Blue') thrives in full sun. It is best to place it in a spot where it can receive at least six to eight hours of direct sunlight daily. Avoid planting in areas that are shaded or overly dim, as this could impede its growth and flower production. Optimal lighting conditions will ensure the brightest color of its striking blue flowers.
TemperatureSea holly (Eryngium bourgatii 'Oxford Blue') is hardy and can withstand a range of temperature conditions. It prefers temperatures between 65 and 75 degrees Fahrenheit for optimal growth. This plant can survive winter temperatures down to about 0 degrees Fahrenheit but will not tolerate extreme heat well, especially if temperatures exceed 90 degrees Fahrenheit for prolonged periods.
PruningSea holly (Eryngium bourgatii 'Oxford Blue') can be pruned to maintain its shape and encourage new growth. Deadheading spent blooms encourages more flowers. Pruning is usually done after flowering or in late winter or early spring before new growth starts. Cut back old stems to the base to promote healthy growth and better air circulation through the plant.
CleaningAs needed
SoilSea Holly (Eryngium bourgatii 'Oxford Blue') thrives in a well-draining soil mix with gravel or sand to enhance drainage. The plant prefers a neutral to slightly alkaline pH, ranging from 7.0 to 7.5. An ideal mix would be part garden soil, part coarse sand or perlite, and part compost to ensure nutrients and proper drainage.
RepottingSea Holly (Eryngium bourgatii 'Oxford Blue') does not require frequent repotting and can be replanted every 2-3 years. It's best to repot in spring, carefully, as its long taproot is sensitive to disturbance.
Humidity & MistingSea Holly (Eryngium bourgatii 'Oxford Blue') tolerates a range of humidity levels and does not have specific humidity requirements but prefers a drier climate.
Suitable locationsIndoor
Place Sea Holly in a bright spot and ensure good air circulation.
Outdoor
Plant in full sun and well-drained soil; avoid wet areas.
Hardiness zone
5-9 USDA.
Life cycleEryngium bourgatii 'Oxford Blue', also known as Sea Holly 'Oxford Blue', begins its life as a seed, which germinates in spring when temperatures are suitable. The plant then develops a rosette of spiky leaves close to the ground, during which it focuses energy on building a strong root system. As it matures, typically in its second year, Sea Holly 'Oxford Blue' starts to produce tall, branching stems topped with cone-shaped blue flower heads surrounded by spiny bracts in mid to late summer. After blooming, pollinated flowers set seed, which can be dispersed by wind or wildlife. The plant then begins to die back in the fall, with the above-ground parts decaying, while the root system may persist through winter, especially in milder climates. The cycle resumes the following spring, either from existing roots or new seedlings if the seeds have successfully overwintered and germinated.
PropogationPropogation time
Early Spring
Eryngium bourgatii 'Oxford Blue', commonly known as Sea Holly, can be propagated most effectively by seed. The best time to sow Sea Holly seeds is in spring or late winter, just before the last frost date, when the soil can be worked. Indoors, sow the seeds in trays with seed starting mix, generally about 1/8 inch deep. It's important to provide consistent moisture and warmth for germination to occur, which might take anywhere from two to three weeks. Once seedlings are sturdy enough, they can be transplanted outdoors to a sunny spot with well-drained soil, spacing them around 8 to 12 inches apart (20 to 30 centimeters). Seed propagation is advantageous because it usually produces vigorous plants that are true to the parent species, provided there's no cross-pollination with other Eryngium varieties.
