What's the key to a beautiful Mother's Day bouquet? Color, you say? Fragrance? The sweet thoughts of the giver? For Eden Prairie-based logistics company C.H. Robinson, which will safeguard the timely delivery of 2,100 truckloads of fresh-cut flowers this year, it's the number 35. At that temperature Fahrenheit, flowers go dormant so they won't bloom before arriving on Mom's mantel. Here's how it comes together:

Day 1: Flowers are harvested, most likely by field workers in South America, which grows 90 percent of flowers imported into the United States. Roses and other delicate flowers are harvested by hand and quickly cooled to 35 degrees.

Day 2: Flowers arrive at Miami International Airport. The airport handles more than 91 percent of all flowers sold by U.S. retailers. In the week leading up to Mother's Day, shipments quadruple to 22 million flowers per day. The perishable cuttings clear customs at lighting speed — in six to eight hours — and the ground race begins.

Day 3: As the flowers move through the customs inspection, the "cold chain" can jump up to 65 degrees. C.H. Robinson deploys a squadron of trucks from an airport parking lot to take pallets of flowers to a nearby warehouse, where plants are chilled back to their magic number of 35 degrees and assembled into bouquets.

Day 4: Refrigerated trucks pick up pallets of flowers from C.H. Robinson's South Florida facility and begin their coast-to-coast journey.

Days 5-7: While maintaining temps in the 35-degree range, trucks fan out to initial distribution centers that serve retailers and supermarkets. C.H. Robinson staffs up to monitor the flowers' journey around the clock. Sensors in the truck alert staff if the temperature gets outside of the magic range. If a nasty storm is brewing, C.H. Robinson will quickly reroute trucks or deploy extra drivers, if necessary.

Days 7-10: The still-cold blooms arrive at the retailers' distribution point where they are put into delivery rotation for transport to stores.

Days 10-12: Fresh-cut flowers arrive on store shelves.

Jackie Crosby