VALUE ADDITION OF FLOWERS THROUGH BLEACHING AND DYEING

Authors: Poonam Kumari and Sapna Panwar
Division of Floriculture and Landscaping
ICAR- IARI New Delhi- 110012
Correspondence address: poonamjaswalfls@gmail.com


Dried and preserved plant materials are essential items in flower trade and also popular for home decor. Dried arrangements, both formal and informal, can preserve the graceful lines, textures, and colors of flowers and foliage with a subtle and gently aged appearance. Many preserved materials will last almost indefinitely with little care. If they become dusty, a careful whisk with a soft brush is usually sufficient to clean them. Dried materials can be used in vases, baskets, plaques, shadow boxes, and fresh flower arrangements. They also may be used as wall decorations, on gift boxes, and in wreaths, corsages, and leis. Brandy snifters, candy jars, terrariums, and other glassware provide dramatic displays for dried materials. Pressed flowers and leaves framed under glass take on a fresh, life-like appearance.

HISTORY

Preserving plant materials in a dried form is not a new idea; it has been considered an art for hundreds of years. Fragrant dried herbs were encased with mummified bodies in Egyptian pyramids. During the Middle Ages, monks dried flowers, foliage, and herbs for use in decorative motifs or for making dyes to color their hand-printed books. Dried flower arrangements have been popular in Europe for centuries, and as early as 1700, colonial Americans used dried flowers to brighten their homes, especially during the dark winter months. Restored Williamsburg presents numerous examples of these designs. With the development of some new preservation techniques, dried materials no longer have to appear withered and somber gray or brown. Plant materials available commercially, as well as those preserved at home with modern methods, are almost unbelievably fresh-looking and represent a wide range of colors. Thus, new areas of creativity are now open to the artistic homeowner.

SELECTION AND HARVESTING OF PLANT MATERIAL

  • Plants for preserving may be collected throughout the year
  • Flowers of various shapes, colors and textures can be collected
  • Try picking flowers at different stages of development
  • Avoid collecting plant material when they are wet
  • Cut flowers and plants with a sharp knife or pruning shears
  • Select plant materials that are insect and disease free
  • Place stems in water while harvesting to prevent wilting. Some flowers may hold color better if allowed to stand in water for a few hours
  • Start the drying process as soon as possible after cutting
  • Strip the leaves from the stem, science foliage on the stems of flowers does not dry properly
  • Splintering herbaceous stems that are 1/4th of an inch or more in diameter will also aid drying
  • To keep the plant samples fresh until you’re ready to preserve them, place them in plastic bags in the shade.

    BLEACHING

    Bleached ornamental plant material provides a striking contrast when arranged with dried or dyed flowers. Bleaching also allows the use of dyes for coloring. Oxidative (Hypochlorite, Chlorite and Peroxide) and reductive bleaching chemicals (Sulphite and Borohydride) are used for bleaching ornamental flowers and foliage. Sodium Chlorite is an excellent bleaching agent because it is relatively selective for lignin without damaging fiber. In reductive bleaches, hydrosulphites (Sodium or Zinc Hydrosulphite) are cheap and have maximum bleaching power. After bleaching with oxidative or reductive chemicals, yellowing of the plant materials is the main problem. To avoid yellowing, multi step bleaching i.e., alternating oxidative bleach with reductive bleach create products with less yellowing. A final wash in a 2 % solution of Barium Hydroxide, Calcium Hydroxide, Sodium Bicarbonate or Aluminium Sulphate prevents yellowing. Coloring Dried Flowers Preserving flowers with their natural colour is essential otherwise we have to improve the color of the product by adding dyes. A dye is most often added to the glycerin preserving solution to permanently color the decorative plant materials. Systemic dyes are available for use. They are acidic–anionic dyes, which are combined with water and glycerin to form a preservation solution that is absorbed by fresh cut flowers and foliage through the stem of the plant. As the water evaporates, it leaves behind the dye and glycerin for our desired color. Normally 1.5 ml to 5 ml dye/l of solution is prepared. Color take and preservation will take 2- 8 days.

    DYEING AND COLORING

    Natural color may be intensified or artificial color introduced to dried plant materials by dyeing or coloring. Flowers are generally very fragile and may need to be dyed before drying, especially if they are to be placed in a desiccant. On the other hand, materials that are easily re-dried, such as many grass seed heads, pods, and dried fruits, may be dyed after drying. Preserving flowers with their natural color is essential otherwise it will be essential to improve the color of the product by adding dyes. A dye is most often added to the glycerin preserving solution to permanently color the decorative plant materials. Systemic dyes are available for use. They are acidic–anionic dyes, which are combined with water and glycerin to form a preservation solution that is absorbed by fresh cut flowers and foliage through the stem of the plant. As the water evaporates, it leaves behind the dye and glycerin for our desired color. Normally 1.5 ml to 5 ml dye/l of solution is prepared. Color intake and preservation will require 2-8 days. Commonly used dyes are Bromophenol blue, Bromophenol red, Bromophenol green, Eosin red, Eosin yellow, Ammonium purpurate, Phenol red as well as food colors.

    METHODS OF DYING

  • Dip dyeing
  • Spray dyeing
  • Absorption dyeing

    1. DIP DYEING Preparation of dye mixtures

    a. Ink or food coloring should be mixed in 1 gallon of water to which 1 tablespoon alum has been added.

    b. Fabric dye should be mixed with water to desired strength.

    c. Floral dip dyes should be mixed as directed.

    Method : Dip either fresh flowers or easily re-dried dry materials in solution until the desired color is obtained. If, by accident, the color becomes too intense, it is usually possible to lighten it by rinsing it in clear water. Colors will lighten in the drying process. Dry the dyed materials by the preferred method.

    2. SPRAY DYEING

    a. Commercial floral sprays : Used as directed, these are not harmful to even the most delicate materials and are available in a wide choice of colors including some metallics.

    b. Ordinary house paints sold in aerosol cans : use only on heavy textured material such as branches, thick or large leaves, seed pods, and cones.

    3. ABSORPTION DYEING (FRESH MATERIALS ONLY)

    a. Florist absorption dyes may be used as directed on can for fresh materials.

    b. Ink, fabric dye, and food coloring should be mixed to a solution stronger than that prepared for dip dyeing. Place stems in the solution and let stand until the desired color is obtained.

    c. Water-soluble (absorption) dyes are sometimes mixed with glycerin and water, thereby causing both the glycerin and dye to be taken up simultaneously.

    COLORING THROUGH GLYCERIN METHOD

  • Coloring dried flowers preserving flowers with their natural color is essential otherwise we have to improve the color of the product by adding dyes.
  • A dye is most often added to the glycerin preserving solution to permanently color the decorative plant materials. Systemic dyes are available for use.
  • They are acidic–anionic dyes, which are combined with water and glycerin to form a preservation solution that is absorbed by fresh cut flowers and foliage through the stem of the plant.
  • As the water evaporates, it leaves behind the dye and glycerin for our desired color. Normally 1.5 ml to 5 ml dye/l of solution is prepared.
  • Color take and preservation will take 2- 8 days.

    COLOR CHANGES DURING DRYING

    general observations regarding color changes that one might expect to occur during the drying As mentioned earlier, color retention is greatest with fast acting methods; therefore, silica gel and microwaving are superior to other methods. The following are some process:
    1. Pink generally becomes red, although borax may turn pink flowers to mauve.
    2. Red generally becomes more purple or bluish.
    3. Pure blue acquires a lavender or purplish color.
    4. Magenta turns to lavender.
    5. Yellow and orange are usually well-preserved and possibly intensified.


About Author / Additional Info:
I am currently pursuing Ph.D in Floriculture and Landscaping from Indian Agricultural Research Institute, New Delhi.