How to Keep Cut Flowers Fresh (2024)

By Susan Martin
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February 2020-Vol.6 No. 2
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2 Comments

With Valentine’s Day approaching, and the gray days of winter persisting, February is the perfect time to review how to keep cut flowers fresh and cheery.

Cut flowers need three main ingredients to preserve freshness:

Sugar to provide nourishment
Citric acid to reduce the water’s pH level. This allows the water to travel through the stem quickly, preventing wilting.
Antibacterial agent to keep down the growth of microflora (bacteria and microscopic algae and fungi). Plant leaves and stems carry bacteria. As soon as you place cut flowers in a vase, bacteria will begin to feed on the nutrients that are released from the base of the stems. As bacteria multiply, they will completely overgrow the cut portion and clog the stem, making it difficult for the stem to absorb the water and nutrients it needs.

DO HOME PRESERVATIVES WORK?

There are many home-brewed recipes for prolonging the life of cut flowers. Concoctions include ingredients such as vodka, gin, apple cider vinegar, mouthwash, Sprite, 7-Up, aspirin, and copper pennies. Each of these remedies provides sugar, acidity, or antibacterial action. But how much of each ingredient should you use? According to the Chicago Botanic Garden and other sources, a purchased floral preservative remains the best solution for extending flower freshness. The preservative will provide the optimal ingredient combination, as long as you follow the directions for the amount of water to add. Most cut flowers are delivered with one small packet, so it is good to keep some floral preservative on hand to use when you change the water. In a pinch, you might just add a couple of drops of bleach to fight bacteria. But a purchased floral preservative is the best option, along with keeping the flowers in cool temperatures.

PRACTICES TO EXTEND FRESHNESS

Several recommendations to preserve cut flowers seem to be broadly accepted. These practices are effective for purchased flowers and for flowers cut fresh from the garden.

Cut flowers from the garden in the cool of early morning or evening.
Bring a bucket of warm water so that the cut flowers can be placed immediately into water; most flowers take in warm water more efficiently than cold. (There are exceptions such as bulb flowers and lilacs.)
Use sharp, clean scissors, pruners, or a knife; dull instruments might crush the stems and keep water from being absorbed
Cut at an angle to help increase surface area for water absorption and prevent the stems from sitting flush on the bottom of the container.
Once you take the flowers inside, re-cut the stems about 1″ at an angle under water. Recut the stems of purchased flowers, as well. Cutting stems under water reduces the chances of air bubbles forming in the stems, which may interfere with the uptake of water.
Make sure the vase is clean and free of any soap residue; if in doubt, wash the container in a solution of one part bleach and nine parts water. Rinse thoroughly before adding flowers.
Fill the vase with warm water and add a commercial preservative that is specifically formulated for cut flowers; make sure the granules are dissolved.
Gently remove all lower leaves or thorns that would otherwise be submerged in water.
Place the vase of flowers in a cool room away from vents and drafts; avoid placing flower arrangements on windowsills and other areas with full sun where flowers can wilt due to overheating.
Do not store flowers and fruit together. Fruits, especially apples, release ethylene gas that shortens flower life.

WATER TEMPERATURE

What water temperature is recommended for keeping cut flowers fresh? Most florists put flowers in water that is between 100-110 degrees, and then place the flowers in a cool area. The idea behind this process is that the warm stems are able to soak up a lot of water while the cool air up top keeps the blooms fresh.

WILTING

Plants continually lose water through their stems, leaves, and flowers. Wilting occurs when the flowers do not take in water as fast as it is used or lost. If you receive a batch of flowers that look somewhat wilted, re-cut the stems, place the flowers in warm water, and then refrigerate for a couple of hours. After that, they should be ready for some room-temperature tap water.

SPECIAL TREATMENTS

Bulb flowers such as hyacinths, iris, daffodils, and tulips have soft stems and should be cut where the green on the stem starts—just above the white bulb. Place the flowers in cold water. Since most bulbs bloom when the air and ground are still at low temperatures, they do better in a vase of cold water.

Roses Photo: Susan Martin

Roses: When cutting roses from the garden, water rose bushes well the night before; then cut roses early in the day before it gets too warm. Roses will last longer if cut just beyond the bud stage with the petals just starting to unfurl. Promptly put the cut roses in a bucket of lukewarm water. Then, re-cut the rose stems under the water to eliminate air bubbles. Next, condition roses by letting them drink up the warm water in a cool, dark room for about an hour. Make sure that most of the stem is under water, but don’t let the bloom get wet. Then, refrigerate at about 38 degrees for at least two hours or until ready to use.

If healthy cut roses suddenly develop drooping heads, it may be due to air bubbles trapped in their stems. Wilted roses may be revived by re-cutting the stem at an angle under water. Then submerge the entire rose in warm water by laying it in a sink or bathtub. After 20-60 minutes, the rose should have absorbed enough water to reinvigorate it. When the flower head hardens to a straightened position, the rose may be placed back in the vase.

Peonies: Peony blooms are often frequented by ants drawn to the sweet peony nectar. Dunk the blossom end of the stem in cool, clean water for 30 seconds to rid the flower of the ants before bringing it into the house. When cutting peonies, leave at least two sets of leaves on the stem so that the plant can continue to thrive. For best vase life, select buds that have just begun to open and feel similar to a marshmallow.If you have too many peonies flowering at once, cut stems can be stored in the refrigerator for two to three weeks, but do not store the stems with fruit. Theethylene gas emitted by ripening fruit will cause petals to drop, and buds to wilt and fail toopen. Refrigerate the peonies upright in water (sometimes tricky to accomplish). The other method is to cut the stems and place them lying down in a plastic bag with a dry paper towel to absorb moisture.

Lilacs Photo: Alisa Anton at upsplash.com

Lilacs: Bring a bucket of fresh, cool water as you cut blooms. Pick flowers in the cool of the morning or evening. Lilacs open very little after harvest, so choose stems that have at least three-quarters of the flowers open. Remove all of the leaves so that the plant isn’t putting its energy into keeping the leaves hydrated. Place stems in the water. Leavethe bucket in a cool, dark place and allow the flowers to take up water for at least an hour. Using heavy clippers, re-cut the stem ends, then slice vertically up the stem 1-2 inches. Grasp one side of the sliced stem and twist backward. Immediately place the cut stems back into the bucket of water. Allow the stems to take up more water in a cool, dark place for another 1-2 hours. The lilacs will then be ready for arranging, and will last 3-4 days.

BEST FLOWERS FOR CUTTING

When considering what flowers to purchase or to grow in our own cutting gardens, it’s helpful to consider what works in the trade. The vast majority of cut flowers are imported from overseas. These flowers ship well and make up the bulk of the flowers used in floral arrangements. They include roses, carnations, Gerbera daisies, garden mums, and orchids. Most of the flowers that local growers focus on are those that do not ship well, or have shorter postharvest vase-lives. These flowers have come to be termed “specialty cut flowers.” Examples of specialty flowers include sunflowers, zinnia, lisianthus, dahlia, ageratum, and peonies to name but a few on this long list. See the list of common types of cut flowers grown for sale in the United States.

Also see the University of Illinois Extension’s seasonal recommendations for Top Perennials for a Cut Flower Garden.