Agapanthus 'Midknight Blue'
A semi‑evergreen agapanthus prized for deep violet‑blue flower clusters carried on sturdy stems around 3 feet tall. It flowers in mid summer and suits sunny borders, poolside beds, and large containers. Among the hardier hybrids, it is often listed for USDA zones 6 to 10 in favorable sites with winter mulch. As with other agapanthus, all parts are harmful if eaten and sap can irritate the skin.
At‑a‑glance
- Group/Class: semi‑evergreen agapanthus hybrid
- Height × spread: 30 to 36 in (75 to 90 cm) × 24 to 36 in (60 to 90 cm)
- Bloom window: mid summer
- Color & flower form: dense umbels of dark violet‑blue florets
- Fragrance: 0 none
- USDA hardiness: 6 to 10 in favorable sites; container in colder zones
- Breeder / Year / Origin: unknown; cultivar name ‘Monmid’
- Cut‑flower notes: sturdy stems; vase life about 10 to 11 days in water, longer with preservative
- Pet safety: avoid
How it differs
- Deeper flower color than many medium blue forms.
- Taller stems than dwarf selections; strong scapes for cutting.
- Notably cold‑tolerant for an evergreen‑leaning type when well mulched.
Strengths
- Bold color masses in mid season.
- Good stem strength for vases.
- Performs in containers and sunny borders.
- Handles coastal exposure when soils drain well.
Care in one minute
- Plant in full sun; light shade only in hot interiors.
- Provide fertile, well‑drained soil; amend heavy clay with grit and compost.
- Water regularly through bud formation; moderate afterward.
- Feed in late spring with a balanced or bloom‑supporting fertilizer.
- Deadhead spent stems; divide congested clumps in spring if flowering declines.
- Mulch crowns in winter where lows drop below about 10°F.
Watch‑outs
- Winter protection advised in the colder end of its range.
- Shade reduces flowering density.
- Avoid waterlogged soils to prevent rot.
Best uses (tags)
borders, cutting, containers, coastal, heat‑tolerant
Provenance note
Sold widely under the trademarked name ‘Midknight Blue’; the selection is referenced in university extension materials under the cultivar code ‘Monmid’.
References
- University of Wisconsin Horticulture – Agapanthus cultivars (incl. ‘Midknight Blue’)
- North Carolina State University – Vase life research (includes ‘MidKnight Blue’)
- Missouri Botanical Garden – Agapanthus (group) profile
- UC ANR – Agapanthus spp. safety note
Written by: Your Flowers Guide editorial team
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