Cut Flowers
Martha Maletta, Home Horticultural Consultant
Dated - July 23, 2004

Fresh cut flowers, harvested and handled with care, can give many days of pleasure in bouquets and arrangements. There are several simple but important steps that will maximize vase-life of garden flowers or those purchased from farm stand or florist.

A flower, once cut, faces several “hazards”, in addition to normal aging, that can shorten vase-life: wilting, reduced water and food supply, poor water quality, attack by bacteria and fungi, bruising and crushing. Good harvesting and handling practices are aimed at reducing these hazards, starting at the beginning with cutting the blooms.

Each flower species probably has an optimal stage at which they should be cut for longest vase-life. There are specific guidelines in commercial flower producer publications, but a general rule is to cut daisy-like flowers as soon as they are fully open but to cut spike or other complex flower-head types (such as phlox) when one-fourth to one-half of the blossoms are open. Experience with a particular plant is a good teacher.

Flowers should be cut during the coolest part of the day when blossoms and leaves are dry. In the morning they are likely to be at maximum water content (fully turgid); in the evening they may have a little more food reserves after a day of plant photosynthesis. Morning or evening, the choice is the gardeners. Bring sharp, clean cutting tools and a clean container with tepid water to the garden. (Tools and containers can be disinfected with a 10% chlorine bleach solution.) Harvesting into a solution containing a commercial floral preservative may be even better.

The type of cut – flat or slanted – is not important but it is essential that it be made with as little as possible stem bruising or crushing that would reduce water uptake. This is why sharp shears or knife is a must. Woody stems can be slit but never crushed. Strip leaves from the lower part of the stem and place in water immediately. A few species exude sticky sap when cut. The cut stem end of these should be sealed immediately by dipping in boiling water for 10 seconds or searing with a flame. Don’t crowd the harvest container to avoid bruising and other damage.

Condition the flowers before arranging by placing the harvest container in a cool and dark place for several hours. To maximize the amount of water uptake the stems can be re-cut underwater at the beginning of this step. This will eliminate any air bubbles that may have entered the stem during initial cutting and could block water uptake. Removing lower foliage, re-cutting and conditioning are important for purchased flowers, too.

Arrange the conditioned flowers in a clean vase with warm water, removing any foliage that would be submerged. Use a floral preservative, if possible, purchasing a commercial product rather than trying to concoct one. The commercial products are specifically formulated to acidify the water, inhibit bacterial and fungal growth and provide nutrients to the flowers. Avoid using water softened by the ion exchange method that increases the sodium content and, if possible avoid fluoridated water.

Change the water or solution when it begins to look cloudy. Can’t see it? Change it after 2 or 3 days, but be sure to check the water level daily because fresh cut flowers can “drink” a lot, especially under warm or low humidity conditions. When some flowers begin to fade, remove them, and always re-cut stems when rearranging.

What about arranging flowers in florists foam? Presoak the foam until it just barely floats. Cutting stems on the slant can help inserting them into the foam and push them in as far as possible, ideally to the bottom. Be sure there is a space somewhere between the foam and the container to check and add water.