Cut Flowers

By Erl Svendsen

Cut flowers can brighten up a room and lift your spirits. They bring a bit of colour and nature into your living space. They’re an appropriate gift for any reason, even when there isn’t a special occasion. And they can be especially helpful in getting you out of the doghouse. Nor do they have to be a gift from someone else: you can buy them for yourself. During the summer, if you’ve planned it just right, you can go into the garden and get your own for free.

One place where cut flowers may be problematic is for a sick friend in a hospital. Some hospitals ban them from patients’ rooms stating health and safety reasons. This may stem from accompanying garden insects or from a long held belief that cut flowers remove oxygen from the air to the point that it impacts a patient’s health and recovery. While it is true that cut flowers (all plants in fact) remove oxygen from the air during respiration, they ‘breathe’ out up to 10 times more oxygen than they absorb.

Now that you’ve given or received cut flowers, the question is how to make them last as long as possible. Flowers, of course, do not last forever and eventually fade as they fulfill their function of producing seed. However, you should expect cut flowers to last for more than just a few days.

There are three main causes that greatly reduce their vase-life (i.e. the length of time that flowers look good in a vase): clogged or reduced water uptake (typically caused by bacteria), ethylene gas and incorrect temperature.

To understand how bacteria reduce vase-life, we need to step back a bit. Water is transported from the vase through microscopic tubes (xylem) in the flower stem and then out into the air through pores in the leaves and petals. If the water flow is impeded for any reason, then the stems and flowers begin to droop or wilt, eventually turning brown and drying out. Plant sap, containing sugars, amino acids and other nutrients, leaks into the water from other microscopic tubes (phloem) in the stem. This is a perfect diet for any bacteria present in the water. Bacteria can be introduced into the vase from many sources: already present in the vase, on the flower stems, from the air, etc. The bacteria build up in vase water and will proliferate around the flower stems, eventually clogging the tubes and restricting water flow.

Here’s what you can do to combat this problem:

  1. Before using, make sure the vase is clean. Swish a little bleach in it to kill any residual bacteria and then rinse it out thoroughly.
  2. Fill the vase with clean water. Use the floral preservative (according to directions) that usually comes with store-bought flowers. Among other things, it acidifies the water and creates an inhospitable environment for bacteria. If you don’t have floral preservative, add 30 mL (2 tbsp) of lemon juice or vinegar plus 5 mL (1 tsp) of sugar to a liter (quart) of warm water.
  3. Remove any leaves that will be below the water level. Leaves may be a source of bacteria and will rapidly decay in water.
  4. Cut new ends on the flower stems with a sharp knife. Cutting a new end will ensure that all the water-sucking tubes are clear of bacterial clogs. Do not use scissors – this will likely crush the stems and the xylem, reducing water flow.
  5. If possible, cut the stems under water to prevent air bubbles from entering and blocking the xylem tubes. This is the reason why some flowers bend just below the bloom shortly after being placed in the vase.
  6. Cut on the stem angle so that the stems do not sit flat on the bottom of the vase.
  7. Replace the water daily.
  8. Recut the stems every third day. Ethylene is an invisible and odorless gas that is naturally produced by plants and is important in fruit ripening and other plant processes. Flowers exposed to ethylene will quickly fade. The good news is that it is fairly easy to deal with.
  9. Do not place cut flowers near ripening fruit, especially apples, pears, apricots, melons, peaches, nectarines, kiwis, papayas, bananas, avocados, pineapple, plums tomatoes, and mangos.
  10. Remove fading flowers promptly. These too will produce ethylene gas causing the rest of bouquet to fade quicker. Cool temperatures will delay the eventual flower senescence, while warm temperatures will hasten flower fading. Too cold a temperature less than 5°C (40°F), however, will result in damage. Again there are easy solutions for dealing with temperature.
  11. Do not place the vase in direct sun.
  12. Keep it away from heat registers.
  13. Do not place atop your TV.
  14. Avoid cold blasts of winter air from exterior doors or leaky windows.

Follow these simple directions and your cut flowers should last one, two or even three weeks.