Six clever ways to keep cut flowers alive

Read on for Sarah Raven's complete guide to keeping cut flowers alive and fresher for longer - © Elena Chaykina / Alamy
Read on for Sarah Raven's complete guide to keeping cut flowers alive and fresher for longer - © Elena Chaykina / Alamy

The truth is cut flowers don't last forever, but garden expert Sarah Raven has some simple tricks for keeping them fresh and maximising their life span so you can enjoy them for longer.

1. Sear your stems

Anything that looks floppy should have its stem ends seared in boiling water for 30 seconds. Give woody stems a bit longer – so bluebells only 10 seconds, whereas lilac needs one minute.

Put 2.5cm-5cm (1in-2in) of boiling water into a mug and plunge the stems in. The amount of stem you sear is to an extent proportional to the length of stem you’ve cut. I sear 10 per cent. If it’s 6ft tall, sear 6in. If it’s 18in, sear 1in-2in. Don’t leave the stems in too long or they’ll cook and disintegrate.

Sarah Raven arranges camassia at the Chelsea Flower Show
Sarah Raven arranges camassia at the Chelsea Flower Show

With short-stemmed plants, take care to keep the flower heads away from the steam. Enclose the flowers in a sheet of newspaper. Searing is easier and works better than burning the stem ends with a match, and you get better results with woody shrubs than by hammering their stem ends.

It has a miraculous effect on vase life. Even if they have flopped already, many flowers will make a total recovery after searing.

2. Add flower food to water

This is important. You can buy proprietary brands in sachets to sprinkle into the vase, or you can make your own.

It should contain some bleach or an acidifying agent, such as vinegar or lemon juice. The bleach or vinegar reduce the proliferation of bacteria.

Tap water is alkaline, which is ideal for many bacteria. By adding a weak acid, you create a hostile environment for the bugs. Bacteria create slimy stem ends that make the vase water stink. It also blocks stems and prevents them from taking up water.

3. Make your own flower food

In a 30cm (1ft) tall vase, use one teaspoon of bleach or a good slurp – about five tablespoons – of cheap clear malt vinegar. The old wives’ tale recommends that you add an aspirin, or half a glass of lemonade, to your cut flower water.

Aspirin contains salicylic acid; lemonade contains sugar and citric acid. And bubbles are created by carbon dioxide, which forms dilute carbonic acid in water.

Proprietary flower food also includes sugar. The sugar feeds the flowers, but in my view, it feeds the bugs too. In our experiments at Perch Hill it seems to add to the vase life of sweet peas, but nothing else.

I always put a drop of bleach in water with strong-smelling plants such as alliums, cleomes and any brassicas, to prevent their characteristic pong from developing.

4. The key to foolproof arrangements

I like arranging stems through a noughts and crosses flower grid. This supports delicate flower heads (or those like camellias with short woody stems) and keeps them just out of the water in your favourite bowl.

For delicate small flowers like snowdrops, put a bunch of several stems through each square. For larger flowers, add just one to each.

It’s worth knowing that turquoise and acid green are both very flattering colours for flowers. Look out for vases in either of those colours. Pewter also looks wonderful – jugs, mugs, bowls and plates.

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5. Use the right kit

I always use florists’ scissors which have stronger blades than normal scissors and their fine tips are less cumbersome than secateurs for small-stemmed plants.

I use traditional metal milk pails for picking my flowers; they look good and are very durable. You can easily carry two, one slung over each arm. You need two; one filled with water for plunging cut flowers into, and the other for stripped leaves.

Floristry buckets are narrower (good for tulips) but they don’t have handles so you can only carry one at a time.

I also have pin-holders in several sizes, heavy metal discs with spikes on the upper surface to hold in place the stems that create the structure of your arrangements. I much prefer using them to Oasis (florists’ foam).

Waterproof glue-tack (called Florafix) is an absolute must-have. Use this to stick pin-holders to the bottom of a vase. You need to use this when both vase and pin-holder are clean and dry, or the stuff will not stick.

6. Give your flowers a break

All plants picked from the garden benefit from a rest before you arrange them. This means giving the flowers a few hours, or best of all, a night, in a bucket of water in a cool, dark place.

Fill the buckets with tepid, not ice-cold, water; the plants absorb it more easily. A rest increases vase life by a quarter or more.

Remember the order:

  • Pick

  • Condition

  • Rest (cool and dark, ideally for 12 hours)

  • Arrange

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