Giant hyssop Agastache 'Black Adder' 5-10 pot P9

Size: Potmaat leidend

5-10cm

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Pot 9x9 cm (P9)

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Benefits according to our specialist

Rich flowering
Low maintenance
Attracts butterflies

Plant features
Description
Planting and care
Packaging and shipping

Genus
Agastache (view all varieties)

Root type
Pot

Pot size
9x9 cm (P9)

Flowering months
July, August, September

Leaf colour
Blue, Purple

Possibilities
Border, Group planting

Soil type
All soil types, well-drained

Positioning
Sun

Winter hardiness
-9,4°C / -3,9°C, USDA zone 8b/9a

Fruit-bearing plants
No

Water needs
Average water

Number of plants per m²
6

Evergreen plants
No

Leaf colour
Green

Fragrant plants
Yes

Growth habit
Upright to bushy growth habit

Height at time of delivery excluding pot/clod
5-10

Mature height (cm)
80

Art. no.
1000042

Description

Agastache 'Black Adder' | Giant hyssop

The Agastache 'Black Adder', commonly known as giant hyssop, is a stunning perennial that brings a burst of deep blue and purple hues to any garden space. This hardy plant, with its spiky inflorescences, thrives in well-drained soils and sunny locations, attracting pollinators and adding vibrancy throughout the blooming months of July to September. The fragrance of the Agastache 'Black Adder' is as delightful as its visual appeal, making it a dual sensory experience.

Key Features of Agastache 'Black Adder'

The Agastache 'Black Adder' boasts an upright to bushy growth habit, reaching an impressive height of up to 80 cm.
It is ideal for border and group planting, creating a dramatic and colorful presence in the garden landscape.
Its flowers, which retain their striking black and blue colors well into the autumn, are a magnet for bees and butterflies.
The plant is not evergreen, but its foliage maintains a lush green color from spring through autumn, providing a fresh backdrop for its vibrant blooms.
It is known for its fragrant leaves and flowers, contributing a pleasant aroma to its surroundings.

Tips for Growing Agastache 'Black Adder'

To ensure a healthy and robust Agastache 'Black Adder', it is recommended to propagate through semi-ripe cuttings or division. This encourages fresh growth and maintains plant vigor.
Although the plant has an average water need, it is not drought-resistant. Regular watering will keep it flourishing, especially during dry spells.
Prune the plant in early spring to promote denser growth and more abundant flowering.
When winter approaches, mulch the base to protect the roots from freezing temperatures, as 'Black Adder' is not evergreen and its foliage will die back.

Ideal placement of a Agastache 'Black Adder'

Agastache 'Black Adder' flourishes best when positioned in full sun, where its vibrant blue and purple flowers can attract pollinators throughout its blooming period from July to September. While adaptable to various soil conditions, well-drained soil is crucial for the health of the plant. Ensuring the soil is not overly moist will cater to its average water needs and prevent issues associated with waterlogging. The fragrant and bushy growth habit of this species makes it an excellent choice for borders and group plantings, where it can reach its ultimate height of 80 cm and spread its delightful aroma.

How do I plant a Agastache 'Black Adder'?

For successful establishment, Agastache 'Black Adder' should be planted in well-drained soil and positioned to receive full sun, which is crucial for the development of its vivid blooms. Planting should be done with care, ensuring each pot-grown specimen has enough space to reach its mature height of approximately 80 cm and an upright, bushy form. Adequate watering upon planting and regularly thereafter is key, as the species has average water needs and is not drought resistant. To promote robust growth, consider the optimal planting period during the milder temperatures of spring or autumn.

Pruning a Agastache 'Black Adder'

Pruning is a vital part of caring for Agastache 'Black Adder', encouraging a compact and bushy growth habit. It is best to prune in early spring, cutting back the previous year's growth to a set of strong, fresh buds. This will stimulate the plant to produce robust new stems, which will bear the striking blue and purple flowers in the summer. Deadheading the spent blooms can prolong the flowering period, ensuring a continuous display of vibrant colors.

Watering a Agastache 'Black Adder'

Agastache 'Black Adder' appreciates consistent moisture, especially during the flowering period from July to September. Regular watering will help maintain its lush foliage and support the vibrant blue and purple inflorescences. It is important to ensure the soil is well-drained to prevent waterlogging, which could adversely affect the plant's health. During establishment, water the plant deeply to encourage the development of a robust root system. Once established, this perennial may tolerate occasional dry spells, but should not be left to dry out completely. In the peak summer heat, monitor soil moisture closely and water as needed to keep the plant thriving.

Fertilising a Agastache 'Black Adder'

To flourish and maintain robust growth, Agastache 'Black Adder' benefits from regular fertilization. Opt for a balanced granular or liquid fertilizer, applying it at the start of the growing season in early spring and once more during the midsummer to support prolonged flowering. The application of fertilizer should be according to the manufacturer's guidelines to prevent over-fertilization, which can lead to excessive foliage at the expense of blooms.

A well-timed feeding regimen ensures that this species has the necessary nutrients to sustain its upright to bushy growth habit and the production of its striking blue and purple flowers. Additionally, a fall application of compost or a slow-release fertilizer can help prepare the plants for the following growing season, strengthening their resilience and vitality.

The characteristics of a Agastache 'Black Adder'

Agastache 'Black Adder' thrives when planted in well-drained soil and a sunny spot, which enhances its vibrant blooms and aromatic foliage. This species is a favorite among pollinators, offering a rich nectar source for bees and butterflies. Its long blooming season extends from midsummer into the fall, providing an enduring splash of color. Additionally, the plant's upright habit and striking purple flowers make it an excellent choice for adding vertical interest to borders and garden designs.

Separating/dividing a Agastache 'Black Adder'

To ensure robust growth and vitality, division of Agastache 'Black Adder' is recommended every few years. This rejuvenation process is best carried out in the cooler months of spring or autumn. Carefully uplift the entire specimen from the soil and gently separate it into smaller, manageable sections, each with a fair share of roots. Replant these divisions promptly, allowing ample space for them to expand and flourish. This method not only stimulates new growth but also helps maintain the health and vigor of this fragrant, upright to bushy species.

What will be the height of Agastache 'Black Adder'?

Agastache 'Black Adder' typically grows to a height ranging from 50 centimeters to 1 meter.

What will be the width of Agastache 'Black Adder'?

Agastache 'Black Adder' achieves a final spread ranging from 10 centimeters to 50 centimeters.

Which soil type is most suitable for the Agastache 'Black Adder'?

Agastache 'Black Adder' is adaptable to various soil types, but it thrives best in well-drained soil. This type of soil allows for proper moisture regulation and encourages healthy growth for the Agastache 'Black Adder' plant.

What is the ideal positioning for the Agastache 'Black Adder'?

The ideal location for Agastache 'Black Adder' is in a sunny area. This plant thrives best when placed in a spot that receives plenty of direct sunlight.

What is the flowering colour of the Agastache 'Black Adder'?

Agastache 'Black Adder' displays stunning flower colors in shades of blue and purple, adding a touch of elegance to its appearance.

Is the Agastache 'Black Adder' hardy?

Agastache 'Black Adder' is considered winter hardy, able to withstand temperatures ranging from -9.4°C to -3.9°C. This places it within the USDA hardiness zones 8b to 9a. As such, Agastache 'Black Adder' is well-suited for enduring the winter conditions within these zones.

Is the Agastache 'Black Adder' evergreen?

Agastache 'Black Adder' is not an evergreen plant. This means that it sheds its leaves at certain times of the year and regrows them at other times.

What is the growth strength of the Agastache 'Black Adder'?

Agastache 'Black Adder' matures and achieves its ultimate height within a span of two to five years, showcasing a moderate yet steady growth rate.

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