Sarah's guide to hardy annual flowers

Posted in All Gardening Advice, Annuals, April, on

Hardy annuals as cut flowers have to be picked - that’s the great thing about them. It’s not picking them that will lead to disaster. Let hardy annuals form seed and they’ve done what the plant’s there for, making babies. Once they’ve reached that stage, they won’t waste much more energy producing masses of flowers.

Most of us British gardeners have a great guilt about cutting flowers – we’re stealing the view - but chuck out that idea and get sowing a few packets of seed to have a house and garden full of flowers in about ten weeks time. Rather than dead-heading, try live heading and pick buckets of flowers for inside.

What hardy annual flowers to grow

I have two rules when selecting what hardies grow:

1) Choose one or two plants that look perfect on their own, ten or fifteen stems plonked in a jug or vase. Someone’s coming round in five minutes time and you want some flowers on the table. You can run into the garden, pick these and have an impressive looking bunch sitting there, ready and waiting.


So which are the best, easy to grow hardy annuals for the instant flower arrangement? The cow-parsley-like, but more delicate and durable, Ammi majus is ideal. It looks good in narrow-necked bottles, a single stem on its own and its wonderful, a billowing white, lacey cloud in any tall jug.

Corn poppies, Papaver rhoeas varieties work well on their own too, but before arranging them, you’ll need to sear the stem ends in boiling water for thirty seconds. The searing water needs to be straight out of the kettle to have the right effect - increasing the surface area for water absorption and preventing the stem tips flopping and petals dropping on to the table below

2) My second rule when selecting hardy annual plants for picking is that I must choose almost as many foliage varieties as impressive flowers. That doesn’t mean endless boring leaves, but plants that provide the background to the more showy, glamorous, centre-stage blooms. In a mixed bunch, I usually use two or three foliage and the same number of flowers to give a varied, garden-like feel. Less foliage and it looks more shop-bought.

Choose foliage to give structure

First, you need some basic foliage, the plants to give a structure and skeleton to a mixed bunch. I’m talking euphorbias here and particularly my number one, all time favourite and most picked plant, Euphorbia oblongata. This flowers for about nine months of the year if you keep picking it regularly, providing the background to Valentine’s bunches and still going strong at Guy Fawkes. In the spring, before the stems have hardened and set with lots of cellulose, you’ll also need to sear the stem ends of these in boiling water before you put them in a vase.

There’s just one word of warning with any euphorbia - pick it with your washing up gloves on. Its milky sap causes an allergic reaction in those with sensitive skin. Any danger is worst on a hot sunny day. Having picked armfuls of Euphorbia characias ‘Wulfenii’ on a bright, late April day three years ago, I’ve now become sensitized to it. My eyes shut up and my whole face swells if I get too much of this stuff on my skin, but it hasn’t stopped me picking it. I harvest euphorbia almost every day, but I do now take care.

If you’re anxious about euphorbia sap, there is an alternative almost as good. Bupleurum rotundifolium looks similar, but is no relation and has thin, dry stems with no sap. If you buy flowers from a florist you’ll recognize it from there. Florists are not allowed to sell euphorbias - too difficult to handle - and bupleurum is what they use instead.

Then you need some foliage fillers. These are easy to find and there are lots of plants that can play this role. My favourite is dill, Anethum graveolens with airy, open, umbellifer-like flowers in a similar euphorbia green. This is the wonderful contrasting companion to my favourite deep, rich crimsons, purples and magentas. The fluffy airiness and colour is exactly the opposite of the rich heaviness that I love so much in lots of flowers.

Last amongst the foliage, you need what I call an upper story – a plant with an interesting silhouette to increase the 3D effect. Seed pods, grasses and flowers with prominent spikes are what you want. My number one is the annual grass, Eragrostis elegans which looks like one of the fibre optic wands children hold at theatres and concerts, lots of thin stems with shiny beads at the end.

Then you need the bloomy flowers. The sunflower ‘Red Sun’ is the most exotic and impressive hardy annual I grow, but the Van Gogh yellow ‘Eversun’ isn’t far behind. You know how sunflowers get wind-burn around their petal edge, brown marks that quickly age the bloom. H. ‘Eversun’ doesn’t get it.

I always sow my sunflowers in the same way – two seeds, two inches apart, pushed into watered soil, up to the first knuckle of my index finger at eighteen inch spacings. Like that, you’ll almost always get one seed germinating and spaced the right distance apart. If both plants in the close partnership come up, dig one up when its four to five inches tall and put it somewhere else.

When the plant is about eight inches tall, you must pinch out the growing tip of any sunflower you grow for picking. Otherwise they grow to ten to twelve feet, with one huge king flower at the apex of the plant and maybe ten lateral flowers on lower branches down the stem. If you pinch out the tip, you prevent the development of the whopper flower, but you quintruple your harvest of the smaller subsidiary blooms. It’s crucial to stake every plant individually. For this I use a four foot bamboo cane sunk nearly a foot into the ground and attach it to the sunflower with a clove hitch knot.

Malope and particularly the silken, magenta variety Malope trifida ‘Vulcan’ is another sumptuous thing to sow. Its bright flowers have a dark veining spreading from the centre to the petal edge and a wonderful zingy-green eye at the heart of the flower where each of the petals attach to the calyx behind. Like the sunflower, it’s quick-growing and reaches a good size by mid-summer.