When cutting flowers, how much stem can I take without harming my bulbs?
Do not remove more than one-third of the leaves when cutting lilies for vases. Lilies are like tulips and daffodils in that they need leaves to build up nutrients for the next season's flowers. Cutting of individual blossoms does no harm. If you cut any lily, do not take more than 1/2 to 2/3 of the stem (leaves) or they will not be able to rebuild themselves to bloom the following summer. Lily bulbs only put up one stem a year, so you need to take care of it. A better choice for cutting would be bulbs that have stems at least 4 feet in height, so there is room to cut off the top and leave enough leaves to nourish the bulb.
If possible, cut flowers early, not in the heat of the day - especially if you plan to transport them out of water to a flower show or to a friend. When air is hot and dry, moisture is conserved in the bulb, rather than in the stem. At night, moisture is "wicked" back into the stem and flowers. Morning is the best time to cut stems so they do not wilt - at least by eight o'clock in most areas.