Dyeing Blue-Purple with Hollyhock — The Cottage Garden Dye of the Ancient World

Use 300-400% WOF of fresh dark hollyhock flowers. For 100 g of wool, gather 300-400 g of fresh flowers. Use ONLY the darkest varieties — deep purple-black or very dark red. Pick flowers when fully open. Remove the green calyx (the cup-shaped base) — it contains no dye and adds unwanted green tannins. The petals should be soft and deeply pigmented. Frozen flowers work well — freezing helps break cell walls and release pigment.

Place the flowers in a dye pot with 4 litres of cold water and soak overnight (8-12 hours). Cold water extraction preserves the anthocyanin pigments better than hot — anthocyanins degrade at high temperatures. The water will turn a deep purple-red within the first hour. By morning, the liquid should be an intensely dark purple. The flowers will have paled significantly as their pigment dissolves.

Warm the pot GENTLY to 60-70°C and hold for 30 minutes. Do not exceed 70°C — anthocyanins are heat-sensitive and break down rapidly above this temperature, shifting the colour from purple toward dull brown. This is one of the coolest dyeing temperatures for any natural dye. Stir occasionally. The liquid will remain a deep purple.

Strain the dye liquor through a fine mesh strainer into a clean pot. Press the spent petals gently to extract remaining liquid. The petals will be pale and slimy — discard them. The strained liquor should be a clear, deep purple-red.

Pre-wet the alum-mordanted wool in lukewarm water for 15 minutes, squeeze gently, and lower it into the hollyhock dye bath at room temperature. Slowly raise to 60-70°C over 15 minutes, then hold for 45 minutes. Turn gently every 10 minutes. The same temperature limit applies — stay below 70°C to preserve the purple. The wool will develop a soft blue-purple to dusty violet. The alum mordant stabilises the anthocyanins and produces a cleaner blue-purple than un-mordanted wool.

Turn off the heat and let the wool cool in the dye bath overnight. Remove, squeeze gently, and rinse in cool water until the runoff is mostly clear. The final colour is a soft blue-purple to dusty violet — warmer and more violet than elderberry, with a gentle, garden-flower quality. Lightfastness is moderate — the purple will soften toward grey-lavender with prolonged sunlight exposure. Store hollyhock-dyed items away from direct sunlight for best colour retention. Dry in shade. Despite the moderate lightfastness, the unique colour and the pleasure of dyeing from your own garden make hollyhock a favourite among natural dyers.