For the longest vase life, harvest when blooms look like a goose neck and have not yet opened. Flowers can also be picked when they’ve opened more, just keep in mind that they won’t last quite as long. Wear gloves when harvesting narcissus, as they ooze a slimy sap that can cause skin irritation. This slimy sap can shorten the vase life of other flowers significantly. To avoid affecting other blooms in an arrangement, you’ll need to “condition” them first. To do this, place freshly cut stems in a separate bucket to rest for 3 to 4 hours to release sap. Do not recut stems after treatment. You can create an arrangement solely of narcissus and the sap won’t be an issue. Expect a vase life of 7 days.