Product description
Favoured heavily by contemporary and gothic garden designers, this striking variety produces wide, saucer-shaped single blossoms in a shade of maroon so incredibly deep it registers to the human eye as a glossy, midnight black. The open structure of the large flowers exposes a prominent, pale central stamen, turning this plant into an incredibly accessible and highly attractive landing pad for local bumblebees and butterflies. It stands out as a sophisticated, moody focal point that entirely redefines the look of a traditional mixed border.
This plant anchors its massive above-ground structure using a single, long, fleshy taproot, you must dig the planting hole exceptionally deep and loosen the subsoil to guarantee the root can push straight down without bending. Once established, this taproot makes the plant highly drought-resistant, but it also means it will violently resent being dug up or transplanted, so you must choose its permanent location wisely. Feed it with a balanced liquid fertiliser just as the first flower buds begin to swell to ensure the dark petals develop their signature glossy, saturated sheen.
Please Note: When purchasing plants, please consider that each live item is unique and may therefore differ from the images shown, which are for illustration purposes only. The plant will be supplied in a growers pot. Depending on season, some plants may be pruned back to encourage growth and deciduous plants may arrive without leaves.
Garden Plant Size Guide

Plants in larger pots can be multiple years older than their smaller counterparts with more mature root systems and foliage. This makes them able to thrive as a full size plant in your garden quicker than smaller alternatives.
The most common size of pot that garden plants come in are 9cm/1L/3L/5L this is in reference to the diameter at the top of the pot.
9cm potted plants still remain the most popular cost effective option though, they just may take a little patience to allow them to grow into full maturity once planted in your garden.
Plant specs, care guide & tips
Key features
Specifications
When to plant
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
Planting and period of interest times are general guidelines and may vary based on your location and conditions. For best results, consult local gardening resources.
Instructions
Top Tip
Cut the towering main stalk all the way down to the ground after the final flowers fade. This aggressive pruning often encourages the Alcea Blacknight to survive and return for another blooming cycle. Leave a few seed pods intact if you want the plant to naturally self-sow nearby.
How to Water
Give the root zone of the Alcea Blacknight a generous soaking once a week during dry spells. Avoid using overhead sprinklers entirely to minimize the risk of foliar diseases. A thick layer of bark mulch helps retain underground moisture without wetting the stems.
How to Plant
Choose a sheltered spot against a solid wall to provide natural structural support. Loosen the surrounding soil deeply because this variety develops a long, strong taproot. Settle the Alcea Blacknight into the earth and smooth the surface to avoid creating a water-catching depression.









