About
Persicaria amplex. 'Blackfield' is a cultivar of Persicaria in the knotweed family Polygonaceae, notable for its summer flowering from July to September. It belongs to a genus of herbaceous plants that can be annual or perennial and shows a variety of stem and root habits. Flowers in Persicaria are carried in spikes, panicles or headlike clusters and may range in colour within the genus. The genus often bears a papery ochrea at the leaf nodes.
About the genus
Persicaria is a genus of herbaceous flowering plants in the knotweed family, Polygonaceae. Plants of the genus are known commonly as knotweeds or smartweeds. It has a cosmopolitan distribution, with species occurring nearly worldwide.
Wikipedia contributors, "Persicaria", CC BY-SA 4.0 — Persicaria
In the garden
Persicaria amplex. 'Blackfield' sits within Persicaria, a cosmopolitan genus in the Polygonaceae (knotweed) family that includes both annual and perennial herbs. The genus displays diverse root systems — taproots, fibrous roots, and in many species rhizomes or stolons — and flowers in spikes, panicles or compact heads; flowering for this cultivar occurs from July to September. Garden handling should reflect those genus traits: expect herbaceous growth and allow room for lateral spread where rhizomes or stolons are present. The presence of a papery ochrea at the leaf nodes is a useful identification feature when checking plants in the nursery. After flowering, cut back or lift and divide clumps where spread is undesirable; removing spent flowerheads after September will keep plants tidy and reduce self-seeding. Use Persicaria amplex. 'Blackfield' where late-summer to early-autumn blooms are wanted; its flowering window bridges high summer into the autumn season and makes it a practical choice for extending interest through that period. Manage stands by annual trimming or occasional division so the cultivar retains vigour and a controlled footprint.
From the Fenn Plants journal
- Notes on DaffodilsWhen to plant daffodil bulbs in the UK, how deep, how to naturalise them in grass, why daffodils stop flowering (“blindness”), and why you should never mix cut daffodils with other flowers.
- Keeping Your NerveHow to garden through a heatwave — the best time to water, why deep soaks beat daily sprinkles, caring for pots and vulnerable plants, and why you can let the lawn go brown.
- Made to LastHow to clean, store and protect garden pots and planters — the frost-proof vs frost-resistant difference, winter care for terracotta and ceramic, and how to reuse a broken pot.
More in the Persicaria genus
- Persicaria amp. 'Blackfield'
- Persicaria amp. 'TaurusKnotweed
- Persicaria amplex. 'Alba'Knotweed
- Persicaria amplex. 'Taurus'Knotweed
- Persicaria rucinata 'Needham's Form'