What Actually Happens in a Flower Vase?

Through a finely branched root system firmly anchored in the soil, the plant absorbs water and nutrients. This absorption and transport occur via complex physical and chemical processes. The stem contains vascular tissues that transport these substances to the outermost leaf and branch tips of the plant, making them available to every cell.

Through what's known as root pressure, water absorbed by the root cells enters the water-conducting vessels. You can observe the forces at work within a plant in spring if you cut a grapevine or a birch branch: liquid will seep from the cuts for an extended period. Water molecules cling tightly to each other, ensuring that the "water column" inside the trunk or stem doesn't break. As water evaporates through the leaves, a suction force is created, much like drinking from a straw, continuously transporting water to the tips.

When the plant is separated from its rootstock, this water column breaks. After some time in the dry air, the plant begins to wilt. If the stem is placed back into water promptly, the transport cycle can resume. However, there's a risk that air may have collected in the vascular tissues in the meantime. This hinders water absorption and necessitates a fresh cut on the stem. This eliminates the air, the water column reconnects, and the flower stem stands upright in the vase.

Along with water, the plant also absorbs dissolved nutrient salts that are essential for its development. For normal growth, a plant needs a variety of so-called macro- and micronutrients. A cut plant doesn't have access to these nutrients, which are normally present in the soil. However, there is a way to supply cut flowers with the nutrients necessary for complete bloom development: by adding flower food (Blumenfrischhaltemittel) to the vase water, the plant's vital functions remain intact.

When the stem is separated from the root, a wound is created. At this point, the plant's vascular tissues are unprotected and exposed to external influences. Bacteria, dirt, fungi, and vascular secretions accumulate at the injury. Bacteria and fungi multiply very quickly in the vase water, increasingly blocking water transport. Further vascular blockages arise from dehydration at the cut surface and from crushing caused by scissors or dull knives. For this reason, flower food (Frischhaltemittel) also contains bacteria-inhibiting substances.