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Kansas State University

Agricultural Experiment Station and

Cooperative Extension Service

COMMERCIAL SPECIALTY CUT FLOWERS

PRESERVING FLOWERS AND DECORATIVE

FOLIAGES WITH GLYCERIN AND DYE

Preserve1. To maintain unchanged. 2. Toprevent organic bodies (plants) from decaying orspoiling. 3. To treat fruit or other plant parts so as to

prevent decay.

The desire to have the flowers of summer inthe house during the winter leads many consumersto purchase preserved plant materials. Florists,interior decorators, furniture stores and mail ordercatalogs display and offer for-sale arrangements ofpreserved plant materials. Craft stores have entiredepartments devoted to dried flowers and glyc-erin-preserved decorative foliages.

Floral materials can be preserved in a variety ofways. The age-old way to preserve flowers is to drythem by hanging them upside down in a warm,dark place. Technology has increased the dryingoptions by including the use of silica gels andfreeze drying. Dried flowers are wonderful to usein floral decorations, but have the characteristic ofbeing brittle.

Using a solution of glycerin and water tosystemically preserve decorative foliages yields afinal product that is soft and pliable and remains sofor several years. The process replaces some of thewater in fresh plant tissue with glycerin. When the

glycerin-preserved foliage is then air dried, and thebalance of water in the plant tissues is evaporated,the glycerin remains behind and acts as a lubricantin keeping the plant soft and pliable.

When a branch (stem) of a plant is cut, it beginsto die. The natural color (chlorophyl and othercolored pigments) will degrade and the tissues of

the plant will slowly begin to turn to their substratecolor (usually a light shade of dead brown). A dyemost often is added to the glycerin preservingsolution to permanently color the decorative plantmaterials. A host of designer colors comprise thepalette when dying preserved foliages.

Instructions for Preserving DecorativeFoliages With Glycerin and Dye

Use only high-quality plant materials. Preserv-ing with glycerin will not improve the quality ofthe plant stem. The dye will not cover or hideblemishes in the foliage. The process will only

preserve the plant material in its present condition.If the edges of the leaves, the leaf margins, aredamaged or dried out before beginning treatment,they will remain so after treatment. The mainportion of the leaf blade will absorb the glycerinand remain soft and pliable while any dry edgeswill remain dry, become brittle and easily breakoff, destroying the appearance of the product. Leafspots or the physical evidence of insect or diseasedamage will not absorb the glycerin solution andoften become more apparent after the preservationprocess. Do not waste time and materials attempt-ing to preserve poor-quality plant materials.

Choice of ContainerThe container should be made of plastic or

glass and not metal. It should be tall and narrow toallow for a greater depth of solution withoutrequiring a large quantity of the preservative.Clean and rinse the container before each use.

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Bacteria and debris left in the container may plugthe conductive tissues of the stem, preventing orreducing the uptake of the preserving solution.

Figure 1. A Container for PreservingWith Glycerin

The Glycerin Solution (recipe for 1 quart) Begin by slowly adding, and continuously

stirring, 1 level teaspoon of concentrated dye to1/2cup (4 liquid ounces) of hot water. Whendye is thoroughly dissolved, set dye solutionaside.

Place 2 1/2cups (20 liquid ounces) warm orslightly hot water into a half-gallon or larger

container for mixing. Slowly stir in 1 cup of glycerin (8 liquid ounces

of 90% or more pure glycerin). Mix throughlybut not so vigorously as to create air bubbles inthe solution.

Add 1/2teaspoon of citric acid (powderedform) to the solution. Stir until dissolved.

Stir in the previously prepared dye solution.

Additional dye may be added, up to a total of 3level teaspoons, to increase the depth of shade.Begin with the 1 teaspoon concentration and

increase slowly based on small trials with eachdye concentration.

Note: use only dyes specified for systemicpreservation of floral products. Consumerfabric dyes generally do not work.

Bunch SizeBunch size must be small enough to allow air

to circulate uniformly around each and every leafin the bunch. Stems must be placed loosely in thecontainer or the leaves on the inside of a tightbunch will not transpire (loose water) at the samerate as leaves on the outside and, therefore, will not

receive the same amount of glycerin. Too narrow ofa container will have the same effect by holding thestems too tightly together to allow for uniformtranspiration at each leaf.

Amount of Solution to UsePlace 1 liquid ounce of preserving solution into

the container for every ounce (weight) of plantmaterial to be preserved. If insufficient preservingsolution is used, not enough glycerin will be placedinto the plants tissue, and the finished product maybe brittle. If too much preserving solution is used,

the finished product may bleed when exposed tohigh humidity. Bleeding is the process whereby theglycerin and dye, within the preserved stem,becomes rehydrated and runs (bleeds) out the cutend of the stem, or may form as droplets of glyc-erin and dye on the leaf surface. The result maystain furniture or walls. Too much or too little isnot a good thing. If you weigh your plant materialsand measure your preserving solution, bleeding isnot normally a problem.

Time in SolutionLeave the stems in the preserving solution until

the solution has been absorbed. For grasses, theprocess may take about 3 to 5 days, for woodystems it may take 5 to 7 days.

Preserving EnvironmentTranspiration, the evaporation of water from

the leaves, is the force that drives the systemicpreservation process. Water, in the form of watervapor, must move out of the plant in order to make

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room for the glycerin and dye solution to move in.The preserving environment should be one whichencourages transpiration at a controlled rate. If the

transpirational rate is too slow, the plant tissuemay die and shut down the system before enoughglycerin and dye have been absorbed. If the tran-spirational rate is too high, water will be lost fasterthan the preserving solution is absorbed andportions of the leaves will dry out and not be ableto absorb the glycerin. The preserving environmentmust be uniform around each and every leaf oreach leaf will transpire at a different rate and createa non-uniform product

The ideal preserving environment will have anair temperature of 60F to 75F, have neitherexcessively low nor high relative humidity, be in

good light, but out of direct sunlight and haveexcellent air circulation.

Harvest and Preparation of PlantMaterials for Preserving

Stems to be preserved should be cut in themorning or early evening when temperatures are alittle cooler. Cut only blemish-free stems(branches). Stems should be harvested mid- to lateseason when new growth has slowed. The ends ofrapidly growing branches have much soft tissue,which may lack structural integrity when pre-served. Preserved branches with droopy ends are

not very attractivethey appear to be wilting.Prepare and measure the solution in the containerbefore going out to harvest branches. Place har-vested branches into the preserving solution assoon as possible after cutting. Recut each stem end,removing approximately 1 inch, as you place them(loosely) into the preserving solution. Keep thebranches clean throughout the harvest process soyou dont contaminate the solution.

Plants Systemically Preserved With Glycerin and DyeAnnual Statice German Statice Pepper Grass (Lepidium)Broom Bloom Grasses Poplar / CottonwoodJuniper & Cedar Salal CandytuftLeaves of woody plants Sweet Annie CaspiaYarrow Myrtle EucalyptusOak Aspen BirchBabys Breath Corn Plants

Post Preservation HandlingRemove stems from preserving container when

all solution has been absorbed. Rinse excess

solution off stem ends being careful not to getremainder of stems wet. Loosely place preservedbranches in a warm, dry, sunny location with goodair circulation for 3 to 5 days to begin the processof removing the balance of water from the stem,and to sun-bleach the chlorophyl out of the leavesand reveal their final color. Then hang the stemsupside down in a warm, dry and darkplace for 2to 3 weeks to complete the drying process. Storethe preserved stems in a dry and dark area untiluse. Avoid storage environments with high relativehumidity and protect from moths and grainbeetles.

CleaningIf your preserved decorative plant materials

become dusty, do not wash them.Use a portablehair dryer, set on low temperature and fan speed,to gently blow the dust off the surface of the leaves.

Sources of MaterialsGlycerin is available in gallons from veterinary

supply stores, drug stores, and through mail order.Systemic dyes can be purchased at many large

craft stores.Pre-mixed preserving solutions can be pur-

chased at many craft stores or by mail order from:Frontier Flowers, Rte. 1, Box 28B, Lakin, Kansas67860; (316) 355-6177.

Large, commercial quantities of glycerin andsystemic dyes are available from: Robert KochIndustries, 4770 Harback Road, Bennett, Colorado,80101.

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Alan Stevens is the Kansas State Extension Specialist for Commercial Floriculture

Brand names appearing in this publication are for product identification purposes only. No endorsement is intended,

nor is criticism implied of similar products not mentioned.

Publications from Kansas State University are available on the World Wide Web at: http://www.oznet.ksu.edu

Contents of this publication may be freely reproduced for educational purposes. All other rights reserved. In each case, Alan Stevens,

Preserving Flowers and Decorative Foliages With Glycerin and Dye, Kansas State University, April 2000.

Kansas State University Agricultural Experiment Station and Cooperative Extension Service

MF-2446 April 2000

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