Remove any labels from the can. Wash the small can with warm, soapy water to remove any dirt and debris. Dry the interior with a towel to remove excess moisture.
Cut the floral foam with a sharp knife so that it remains 1 inch taller than the small can. Soak the foam in a bucket of distilled water for 30 minutes to 1 hour so it stays moist for the fresh flowers.
Cut 1/2 to 1 inch off the bottom of each stem at a 45-degree angle to help the flowers absorb the water. Place the stem end of the fresh flowers in a bucket of room-temperature water to keep them fresh.
Place waterproof tape at the bottom of the small can to hold the foam in place. Press the floral foam into the small can carefully.
Wrap any fragile and delicate stems with floral tape before you insert them into the foam. Remove the lower leaves from the portion of the stem that you will insert into the foam.
Insert the flowers into the foam carefully. Start around the outside of the container and work your way toward the center. Trim the flower stems you insert on the outer perimeter so they sit lower than the flowers you place in the middle.
Add greenery to any gaps in the flower arrangements so the foam is not visible.