We have found 27 plants that meet your criteria.

hollyhock
Alcea rosea 'Nigra' hollyhock Tall stems bearing near-black flowers £1.49 Buy
granny's bonnet
Aquilegia vulgaris var.stellata 'Black Barlow' (Barlow Series) granny's bonnet Striking dark purple, double flowers £7.49 Buy
granny's bonnet
Aquilegia vulgaris 'William Guinness' granny's bonnet Unusual purple-black flowers £7.49 Buy
clematis (group 3)
Clematis 'Black Prince' clematis (group 3) Beautiful deep purple flowers £12.99 Buy
clematis (group 3)
Clematis 'Warszawska Nike' clematis (group 3) Sumptuous deep purple flowers, £9.99 Buy
dusky cranesbill
Geranium phaeum dusky cranesbill Small, deep maroon flowers. Good for groundcover £7.49 Buy
dusky cranesbill
Geranium phaeum var. phaeum 'Samobor' dusky cranesbill Small, purple-black flowers. Good for damp... £7.49 Buy
spencer sweet pea seed Beaujolais
Lathyrus odoratus 'Beaujolais' spencer sweet pea seed Beaujolais... One of the darkest forms £1.89 Buy
poppy
Papaver somniferum (Paeoniiflorum Group) 'Black Paeony' poppy Big, blousy, near-black blooms £1.99 Buy
black elder (syn. Black Beauty)
Sambucus nigra f. porphyrophylla 'Gerda' (PBR) black elder (syn. Black Beauty)... Dramatic purple foliage £10.99 Buy
sweet scabious
Scabiosa atropurpurea 'Black Knight' sweet scabious Opulent colour for the border £2.99 Buy
beard tongue
Penstemon 'Raven' beard tongue Dramatic, deep purple, foxglove-like flowers £6.99 Buy
Crocus Special Offers
New Tulip collection Buy 30 tulips for £18.95 + get... NOW £0.00 Buy
daylily
Hemerocallis 'American Revolution' daylily Large, deep blood-red flowers in summer £8.49 coming soon
New
spencer sweet pea Beaujolais
Lathyrus odoratus 'Beaujolais' spencer sweet pea Beaujolais One of the darkest forms £6.99 coming soon
Price Pruned
tree peony / tree paeony
Paeonia delavayi tree peony / tree paeony... Tree peony with deep, maroon flowers NOW £19.99 coming soon
pincushion flower
Scabiosa atropurpurea 'Chile Black' pincushion flower Deep claret, almost black flowers £6.99 coming soon
New
hyacinth
Hyacinthus 'Dark Dimension' hyacinth Darkly delicious £3.99 coming soon
moor grass
Sesleria autumnalis moor grass Perfect for informal edging £7.99 coming soon
double late tulip bulbs
Tulipa 'Black Hero' double late tulip bulbs Almost black double flowers £5.99 coming soon