Agastache 'Black Adder'
Hyssop
- Height × spread
- 0.75m × 0.45m
- Position
- Full sun
- Hardiness
- Very cold to -20C (RHS H6)
- Flowers
- Summer, Autumn
Availability
Please ask in store about availability
Many plants are seasonal. Call 01234 567890 to check current stock.
About this plant
A dramatic plant when grown in quantity. The long slender flower spikes are coloured dark green and packed with tiny deep purple blue flowers. Grow a regiment for impact. It flowers from July to September and stands around 75cm in height with a 45cm spread.
- Flower colour
- Blue, Purple
- Foliage colour
- Green
- Variegated
- No
- Scent
- No
- Shape
- Column
- Height
- 0.75m
- Spread
- 0.45m
- Season of interest
- Summer, Autumn
- Flowers in
- Summer, Autumn
- Evergreen
- Deciduous
- Garden style
- Small scale garden, Prairie garden, Cottage garden
- Sun or shade
- Likes full sun
- Soil type
- Gravelly soil, Sandy soil
- Soil pH
- Acid (ericaceous), Alkaline
- Drainage
- Well drained soil, Dry soil, Drought resistant
- Hardiness
- Very cold to -20C (RHS H6)
- Borders & containers
- Borders
- Use for
- Ground cover, Bee attraction, Butterfly attraction
- Hazards
- No
AutumnNow
Autumn-Spring · Planting
Prune flowering stems
Two choices: in mid-late autumn cut spent flowered stems back to near ground, avoid damaging the very young growth at the base. Or leave them for the architectural effect of the their foliage, and cut back in spring, avoiding the young growth.
Spring
Spring-Autumn · Outdoors
Water during drought
In drought conditions where established plants in the ground have had no water for a month, do a deep watering. If drought continues repeat after a fortnight. Plants only need watering during spring to autumn growth. Check plants in pots more often.
Established plants have a good degree of drought tolerance. Water after a prolonged period of drought. Many drought tolerant plants can rapidly revive, even when much of the foliage has died. They will respond with new growth.
Spring - early-mid · Planting
Divide when too large
The plant can be divided if it becomes too large or another plant is required. This may involve physically dividing the clump in two, removing offsets or small bulbs or dividing rhizomes. The new plants can be grown in pots or planted in the ground.
Spring - mid · Planting
Prune to the ground
Plants that have been left all winter for the architectural effect of their foliage can be cut to the ground in spring, being careful not to damage the young growth that will just be emerging.
Summer
Summer - early · Outdoors
Feed a general fertiliser
Where plants have moderate needs for nutrients, they can simply be given a general feed, fairly early in the growth season so that the growth has plenty of time to harden off before the cold weather.
Give plants a general boost with the application of a general purpose fertiliser which is spread around the root area of the plant, with amounts as directed on the feed label.
Summer · Planting
Deadhead - remove dead flowers
Cut off dead flowers to encourage the development of new ones. In late summer the seed heads can be left for their architectural value in winter. If this is unappealing, cut the plant to the ground in autumn.
Deadheading (cutting off the flowers) induces the plant to provide further flowers.