Choosing Materials

Always begin with fresh and healthy materials (unless dried materials are elements of your arrangement). 

If you are cutting from a garden, cut early in the morning when plants are hydrated and not effected by the hot sun. 

Preparation

Use a deep wide mouthed bowl for cutting flowers under water. It allows you to submerge the stems and still have enough space to cut comfortably. Cutting under water allows the water to rise up the capillary system of the stem instead of air which will clog the passages. Repeat cutting under water every one to two days.

Place cut plants in warm water (30°C/86°F) for faster absorption.

Store types flowers in separate containers if possible.

To prevent bacteria from growing: clean containers well after each use. Use a small amount of bleach in the water. That will also keep the water clear in a transparent container. Remove foliage from parts of stems that will be under water.

Special Care

Arrange flowers from bulbs (Tulips, Hyacinth, Daffodils etc.) in shallow water.

]When using Chrysanthemums in an arrangement, give them a special treatment by showering them.  Sprinkle water on the backs of the leaves. this will keep the flowers looking fresh for a longer time. If stems are weak, dip in hot water.

Dip Coleus stems in boiling water for a few seconds, then let them stand for a while in cold water.

Dip the cut end of Dahlias in hot water, then place in deep water.

Flowering branches (Cherry, Quince, Plum, Viburnum etc.) need a bit of work to allow maximum water absorption. Shave off the outer layer of the lower stem and then cut upwards to form an X across the bottom of the stem.

Add alcohol to the water for Gerbera Daisies.

Cut Grasses under white vinagar.

Hydrangeas drink from their petals too, so mist the petals as well as putting the stems in water.  In fact, most flowers do well with misting, especially if it is hot and for arrangements done in advance of your events and special occasions. Misting them keeps them fresh.  Leaves can use as much water as the flower so think about discarding any that are not essential. Dip stems in alum after cutting under water.

Shave off the outer layer of the lower stem and then cut upwards into the stem multiple times creating a shredded look for woody-stemmed flowers, such as Lilac. Dip the ends of lilac in alcohol.

Wet the stems and apply alum to the bottom and sides of cut Peonies. Cover about three inches from the bottom the stems.

Poppies need to be cauterized before adding to water. Burn the bottom inch or two of the stem with a lighter or other fire source after a fresh cut before placing in cold water.

Spray Pussy Willow catkins with hairspray to help keep them intact. Water will make the catkins sprout.

Store Roses in a separate container from other flowers especially flowers from bulbs. Remove 2 cm/1” of bark and use sweetened water (add clear carbonated soda). Do not include Dahlias in the arrangement if you sweeten the water.

Remove the leaves to enhance color and water absorption of Spiraea. Break stems instead of cutting to prevent crushing the soft xylem.

Add salt to the water to lengthen the life of Sunflowers. Use the freshest flowers possible.

Add pennies (minted before 1983) or small pieces of copper pipes to water for Tulips.

Reviving

When you know the flower is fresh, but the flower head is hanging, there is probably an air bubble stuck inside the stem.  When you cut the stem two or three times under water and keep the flower stem in the water for 10 to 15 minutes, the flower can drink again and will straighten.

Often submerging the head (hydrangea) or entire flower (bupleurum) will revive wilted stems. Wrapping stems in moist newspaper for a few hours can also be effective. Roses respond to submerging the stems in warm water keeping the head above the water line.

Utensils   

A good small wire cutter is handy. Never use your ikebana scissors for cutting wire.

A knife comes in handy to prune some heavy branches, or to shape materials. 

Tape is often used as an adhesive bandage when branches or flowers are broken.  It is also used to thicken the stem of flowers before they are placed in a kenzan. 

Aluminum wire can be used to make a structure in the containers to fix or hold the plant material.  The wire can also be used as part of the design.