Cut flowers: cutting and conditioning / RHS Gardening (2024)

The flowers, foliage, stems and seed pods of a range annuals, perennials, bulbs, as well woody plants, can be used for flower arranging See cut flower growing and selectionfor more information.

Time of day

• For best results, collect cut flowers in the morning when their stems are fully turgid (filled with water)
• Avoid picking during warm and sunny conditions as the plants will be water-stressed. Wait at least until the evening when they have had a chance to recover
• Place the stems straight into a bucket of water or as soon as possible after cutting

Stage of development

• Most flowers are best picked when they are just starting to show colour. Those in full bloom will go over more quickly. However, the flowers of some plants ,such as roses and dahlias, may not fully develop if picked in tight bud
• Pick blooms in a spike arrangement, such as foxgloves and gladiolus, when the lowest flowers have just opened. However, wait until most flowers are open before cutting delphinium spires

Frequency

• Many annuals, such as sweet peas, and some perennials will bloom over a longer period if picked regularly
• Pick lightly and infrequently from slower-growing shrubs to avoid stressing the plant. Picking is a form of pruning, and heavy pruning may result in fewer flowers the following season

Precaution: It is best to use gloves when picking and handling cut flowers. All parts of some flowers, such as monkshood (Aconitum), are poisonous; others can cause skin irritation. See thepoisonous plantspage for details

Conditioning is preparing the cut flowers to prolong their longevityin displays and ensure they look their best. Condition the cut stems by following these five simple steps:

1. Strip all the leaves from the bottom half to two-thirds of each stem. As a general rule, any foliage below the water level should be removed to prevent it rotting in the water
2. For best results, re-cut all stems. Use a sharp knife or secateurs to avoid crushing the stems and reducing their ability to take up water and nutrients
3. Cut the stems to length with a clean, angled cut without leaving jagged edges that could lead to decay
4. Place prepared stems in a bucket of clean water and leave in a cool place for at least two to three hours or, ideally, overnight. This will allow the flowers to drink before being brought into a warmer environment
5. Some plants with soft stems and heavy flower head, such as tulips and gerberas, are prone to bending. If left, the stem will remain in this position. To straighten the stems, wrapthe bunch flowers in newspaper and stand them deeply in water for at least two hours –ideally over night

Special requirements

• Woody flower stems (roses) should have an additional vertical cut through the base of the stem to a length of about 5cm (2in)
• Hammering the bottom of woody stems is often suggested, but this may increase the rate of bacterial infection and is not usually necessary
• Stems prone to drooping, such as poppy, euphorbia, smyrnium and hellebores can be sealed by dipping the bottom 2.5cm (1in) of the stems into hot water (just off the boil) for 20-30 seconds. Always wear gloves when handling euphorbia to protect skin from its irritant milky sap
• Try to revive drooping roses with the hot water treatment described above. Remember to re-cut the stems first
• Condition the stems of plants with hollow stems such as delphinium, amaryllis and lupins by filling the stem with water. Plug the stem with cotton wool and tie a rubber band around the base to keep the plug in place and prevent the stem from splitting

In the vase

• Always use clean vases. If dirty, wash thoroughly with detergent and a bottle brush
• Dissolve some cut-flower food in the water before placing the flowers in the vase. As well as feeding the flowers, this will also help keep the water clean as it contains an anti-bacterial treatment
• Check the water level every couple of days and top up as necessary
• Change the water and re-cut the base of the stems every two to four days, re-cutting a little off the bottom of the stem each time
• Remove any dead or dying flowers to keep the arrangement looking fresh for longer
• Position the vase in a cooler spot in the room away from source of heat such as radiators and fires

Home made plant food

A home-made preservative is unlikely to be as effective as a proprietary one but is simple and cheap to make.

To make a one litre of the solution

• one litre of water
• one tablespoon of vinegar
• one teaspoon sugar

Stir the water thoroughly before adding the flowers.

Problems to look out for;

• Drooping stems are likely to be a result of lack of water or poor water uptake. Top up water regularly. Re-cut the stems. Try treating the cut end with hot water. Check in literature or on website if any particular treatments are recommended
• Flowers aging prematurely. Keep arrangements in a cool spot. Change water regularly. Feed the flowers and prevent bacteria build up by adding cut flower food in the water. Keep away from ripe fruit
• Buds not opening due to being picked to early, especially roses. Pick in loose bud in the future
• Water in the vase becoming murky or smelly. Change water more regularly and ensure vases are thoroughly cleaned before use
• Small black pollen beetles coming out of flowers whilst in the room. Before bringing into the house, place the bucket for a day in a dark shed or garage with a door or window open. The pollen beetles will be drawn to the light, leaving the flowers inset free
• Earwigs can be troublesome, especially on dahlias, damaging the flowers. They can be also brought into the house on the cut flower stems

The Cutting Garden by Sarah Raven (Frances Lincoln Ltd. 1996, 0-7112-1047-0)

The New Flower Arranger by Fiona Barnett (Lorenz Books 1995, ISBN: 1859670806)

Allan M. Armitage'sSpecialty Cut Flowers by Allan Armitage (Timber Press 1993, ISBN 0-88192-225-0.1)

Postharvest Handling and Storage of Cut Flowers, Florists Greens and Potted Plants by Joanna Nowak and Ryszard M Rudnicki (Timber Press 1990, ISBN 0-412-37350-5)

Introduction to Floriculture edited by Roy A Larson (Academic Press 1992, ISBN 0-12-437651-7)

These books are made available through the RHS Lindley Library.