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This month . . .

Preserving Buds and Blooms
Drying Summer's Hues

The vibrant blooms of summer captivate our senses and imaginations, then so quickly fade away. But the story doesn't have to end like that. You can extend your students' fascination with flowers, adorn your classroom, and inspire a host of hands-on projects by doing what humans have done for thousands of years: dry 'em.

"Everlastings," such as statice and strawflowers, are practically dry to begin with. But most blooms need a nudge to maintain their colors and shapes when dried. That's where the fun begins.

Preserving plants by drying them is hardly a new idea. Remnants of dried flowers and herbs have been discovered along with mummified bodies in Egyptian pyramids. Monks during the Middle Ages dried flowers and other plant parts for decorations, medicinal uses, and dyes. In the 18th century, Europeans and colonial Americans used aromatic dried flowers and herbs to repel insects and cover smells resulting from a lack of fresh water and refrigeration. Crafts and decorations made from dried flowers also brought color and promise to homes through bleak winters.

Science, art, and even history can be woven into a flower drying project. After all, there's more than one way to dry a flower, and different variables that affect the outcome. As students test various flowers and drying regimens, gather data, and make sense of findings, they think and act like scientists. Important concepts are revealed as keen observers explore the transitions from bud to bloom or the interaction of water, light, and pigment. A class can dig into the historical "language" of flowers or create bouquets, wreaths, potpourri, and other crafts to give as gifts or sell to raise funds. Read on for inspiration and advice.



Drying Summer's Hues

 Most plant parts — flowers, leaves, stems, cones, and seedheads — can be easily dried, but here we focus mainly on flowers from the garden and wild. One of the easiest means of preserving flowers and their vibrant hues is to air-dry them in hanging bunches. But not all budding blossoms take to this scheme. Those that are fragile or moist, such as pansies and poppies, dry better when covered with a substance, like silica or sand, that helps draw the water out. Yet another approach (if you don't mind flattened flora) is to press blooms and other plant parts. Whichever method you use, the basic principle is the same: to remove moisture slowly while maintaining as much of the original shape and texture as possible.

Below we offer guidelines for different drying strategies. Your students might get their feet wet by following some of these "recipes," and then invent and experiment with different approaches and variables. The Curriculum Connections activities offer ideas for digging deeper.

Materials

  • Air-Drying: pruners or sharp scissors; string or rubber bands; pole, drying rack, or other means of hanging flower bunches; newspaper or dropcloth
  • Using Drying Agents: pruners or sharp scissors, shallow airtight plastic or glass container; drying agent such as silica gel (a granulated drying agent you can find at florist or craft suppliers), sand, and/or cornmeal
  • Pressing Plants: squares of corrugated cardboard, sheets of newspaper, 2 plywood boards (all cut to the same size); something to bind the stack (belt or bungee cord) or weight it (heavy books or bricks).

Growing and Gathering

Flowers that dry well are typically colorful, compact, strong-stemmed and relatively low in moisture content. The chart at the bottom of this page lists ideal flowers to grow and/or gather for drying. In flower drying, as in life, timing is everything. Your schoolyard sleuths should keep eyes peeled for flowers that are just beginning to reach maturity. Other flowers on the stem or plant may still be partially closed, but that's okay; the blooms will open more as they dry. Try to avoid harvesting flowers when they're already at their peak or beyond; they'll tend to look "over the hill" when they dry. (You might ask students whether flowers on a spiky stem, such as delphinium, open top to bottom, or bottom to top, and let them observe what happens over time!)

The best time to pick flowers for drying is mid-morning when the dew has dried but before they're wilted from heat and sun. For most flowers, you'll want to take as much stem as possible and make a clean, angled cut with a sharp pruner or scissors. Remove excess leaves on the lower part of the stem. If you're drying blooms that have weak stems, or those that weaken as they dry (e.g., strawflowers, globe amaranth, and immortelle), leave an inch of stem or less and plan to replace it with florist's wire before you dry the flowers. (You can later wrap the wire support with florists' tape to camouflage it.) Keep the cut blossoms out of sunlight to maintain good color. Once they're dried, you can bring them into the light.

Air-Drying

Sturdy flowers with relatively low moisture contents (see chart, below) generally air dry very well as long as you follow some simple rules:

  1. Find a relatively dark, dry, airy spot (a hallway or attic, for instance) for hanging flower bunches. (Low light is okay, but direct light will drain flower color.) If there is little air flow in your drying area and/or if you're in a humid area, you can use a fan to increase air circulation.

  2. Make flower bunches that are no more than 1 1/2 inches thick at the bottom and bind each bunch at the bottom with string or rubber bands.

  3. Challenge students to design a system for hanging their flower bunches. For instance, they might create a clothesline effect with horizontal poles or ropes, or build a drying rack. (Bent paper clips make perfect hangers for bunches.) Place a newspaper or a dropcloth under the bunches to catch fallen leaves and petals.

    Note: Some flowers dry better rightside up. This is often true for large blooms, such as sunflowers, many-flowered blooms, such as queen Anne's lace and dill, and seedheads, such as those from poppies. Try putting stems of these types of plants through a piece of wire mesh (e.g., hardware cloth) so the flowers lay flat and the stems dangle below. Better yet, have your students invent a unique drying method.

    4. Look for signs of drying. The process can take from 10 to 20 days, depending on the plant. The stems should snap easily when the flower is thoroughly dry. Students might also dissect one or two flowers to make sure there is no moisture inside — and learn a bit about flower anatomy, to boot. If you're saving flowers for a craft project or sale later in the year, wrap them in newspaper and place them inside a cardboard box with air holes in the sides.

Using Drying Agents

 Another common method for drying flowers involves covering them with something that draws moisture out, generally referred to as a dessicant. Here are some tips on using several drying agents: silica gel, sand, and homemade mixtures.

Silica Gel
 Silica gel, which is available from florists and craft shops, is not actually gel-like, but granular. It dries most flowers quickly — generally in three to four days — with good results. Although it is relatively expensive, you can reuse it indefinitely as long as you dry it out between uses (see below).

  1. In a shallow airtight container, spread the flowers on a 1-inch-thick layer of silica without crowding them. You may want to remove very thick stems and replace them with florist's wire so you won't have to use as much silica.Your students might want to try different flower orientations to see which best preserves the original shape. (For instance, some people recommend putting flat flowers, such as daisies, facing down. Carefully spoon more silica on top until you've covered the flowers with at least another inch of crystals, trying to keep the petals in their natural positions. If your container is tall enough, you can even make alternating layers of flowers and silica.

  2. Seal the container and leave it for at least three days before checking on the flowers. (If you don't seal the container, the silica will absorb moisture from the air.)
    Salvaging Sunflowers
    Kids love sunflowers, but these blooms can be challenging to dry. One trick is to keep about 2 feet of stem attached, cover the flower head with silica gel crystals, and let the stems hang over the side of the container. Seal the whole setup in plastic wrap and leave it untouched for a week to 10 days.
    Students may also want to try speeding up the process by using a microwave oven. To do so, put the silica-filled, sealed container in for about 3 minutes at medium power. Allow 15 minutes for it to cool before opening the lid. If the flowers aren't dry, you can put them in for 30 more seconds, remembering to let the contents cool each time. Do some flowers respond better to this treatment than others? What observations and generalizations can students make? (Students can also experiment by placing blossoms in folded paper towels directly in a microwave and putting a dish on top to prevent curling. Set the oven for 2 minutes on high as a starting point.)

  3. Gently shake the fully dried blooms or lightly brush off the crystals. Once the flowers are dry, you can use them for arrangements, wall hangings, potpourri, field guides, and other creative projects your students dream up.

  4. Dry the silica gel so you can reuse it. Most silica gel products turn pink when they've absorbed moisture and blue when they're dry enough to use. (Other products remain white.) If your silica turns pink, you can dry it out by baking it in a 200 degree F oven for several hours until it turns blue. Always keep silica gel stored in an airtight container.

Sand Mixtures
Clean, dry, fine, sand is one of the oldest, least expensive dessicants used. However, it dries more slowly than other agents and is heavier, so it can bruise delicate petals. Follow the same general steps as detailed above. You'll need to use at least 2 inches of sand over and under the flowers. Expect the drying time to be at least 5 to 8 days. Here's a mixture that many gardeners say is more effective than pure sand: 3 parts borax cleaning powder, 2 parts dry "hobby" sand, and a tablespoon of salt per quart of mixture. Is it, indeed, more effective? Challenge your budding scientists to find out!

Other Homemade Concoctions
Because pure borax can burn or bleach delicate flowers, flower driers often mix it with other substances such as cornmeal, Wheatena, or Cream of Wheat. Start with a ratio of 1 part borax to 3 parts of one of the other ingredients. (The more borax, the faster the blooms should dry.) To speed up drying, add 1 tablespoon of salt to each quart of mix. Have students brainstorm other types of readily available materials that might absorb moisture. (Consider kitty litter, perlite, or sawdust.) Next, experiment to find out which ones, alone or in combination, are the best preservatives.

Pressing Matters
Pressing flowers is an easy way to preserve them, if you don't mind a bit of flattened flora. It's an ideal approach if you want to use the blooms for field guides, herbaria, note cards, and other creative projects where flatness is fancied.

The simplest approach involves pressing flowers in an old telephone book, but here's a better strategy: Place several sheets of uncoated paper, such as newsprint, on a square of corrugated cardboard. Lay a batch of flowers on the paper pile with space between them. Continue to add additional layers of flowers and paper, ending with a sheet of corrugated cardboard and a board. Press the entire sandwich down with a heavy object or bind the stack with a strap, rope, or bungee cord. It should take from 10 days to 4 weeks, depending on flower type and other factors, to complete the drying process.

For thorough guidance on pressing flowers, projects from herbaria to pressed plant bookmarks, and related resources, click to the June 2002 issue of the Growing Ideas Classroom Projects News: Collecting Plants: A Pressing Project.


Flowers That Preserve Well*

Annuals

 

Good for air-drying

acroclinium, bachelor's button, bells of Ireland, celosia, chive, globe amaranth, immortelle, larkspur, love-in-a-mist, salvia (blue), statice, strawflower

Best dried with a dessicant

aster, calendula, cosmos, dahlia, marigold, pansy, zinnia
Perennials anise hyssop, astilbe, artemisia, baby's breath, bee balm, chrysanthemum, delphinium, heather, lavender, liatris, sea lavender, rose, tansy, veronica, yarrow chrysanthemum, coreopsis, dianthus, painted daisy, rose
Herbs chives, oregano, rosemary, sage, thyme  
Wildflowers

(Never pick a flower that seems to be in short supply in an area or that you know to be endangered.)

goldenrod, milkweed, pearly everlasting, queen Anne's lace, teasel, thistle

 

 blanket flower, wild sunflower, black-eyed Susan
 

* Many seed heads and pods also dry well and add interest to dried flower creations. Try preserving the seed containers from these plants: baptisia (false indigo), Chinese lantern, love-in-a-mist, oats (and many other types of grasses), money plant, and purple coneflower.

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Copyright© 2003 National Gardening Association

  

Contents

Pg. 1: Drying Flowers

Drying Summer's Hues

Materials

Growing and Gathering

Air-Drying

Using Drying Agents

Pressing Matters

Flowers That Preserve Well


Pg. 2: Curriculum Connections

Dried Flower Creations

Budding Science Investigations

Explore the Language of Flowers


Pg. 3: Resources

Web Sites We Like

Flower Items from the
Gardening with Kids Store


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