Lesson 6
Vase life and arrangements
Pick cosmos as the bud is showing colour and just beginning to crack open — at this stage they will continue to open in the vase and last days longer.
Strip leaves below the waterline (cosmos leaves rot fast). Plunge into deep cold water for an hour before arranging — this conditions the soft stems.
Cosmos is the easiest 'filler' flower in the world; almost any other flower mixes well with it. Wide-necked vases suit cosmos best — their natural movement gets crushed in narrow jars.
What to add to vase water (per 1 litre)
- 1 teaspoon of sugar — feeds the flower in place of the stem it lost.
- 1 teaspoon of lemon juice OR clear (white) vinegar — lowers the pH so water moves up the stem more easily.
- 2–3 drops of household bleach OR a clean copper coin — stops the bacteria that block the cut stem (the real reason vases go cloudy and flowers droop early).
- Change the water every 2 days and recut 1 cm off the stem each time. That single habit beats any other 'trick' for vase life.
- Florist sachets (Chrysal, Floralife) are this same recipe pre-mixed — convenient, not magic. Either is fine.
- Avoid: aspirin, copper pennies post-1992 (not real copper), and full-fat lemonade — the sugar load encourages slime.
Cosmos in the vase
- Cut at the cracking-open bud stage, never fully open.
- Plunge stems into cool deep water for 1 hour before arranging.
- Wide-necked jug, not narrow vase — let the stems splay.
- Recut every 2 days; cosmos drink less than dahlias but still notice.