A cut above: the top annuals for summer
Which annuals are best for summer vases and pots? Sarah Raven puts them on trial
Ilove a trial – collecting together related plants, working out how to assess them, and then seeing how they do. Gardening by spreadsheet may seem odd, but it gives you an easy way to compare similar plants and find out which varieties are the standout performers. Last year, we had 20 new-to-the-market annuals in a cutting garden trial and this year we’ve looked at a similar number, with some front-runners already.
We have seven different categories in which every potential cut-flower plant is assessed. The first is: how long do they take from seed to flower? It’s useful to have quick producers, which don’t fill their ground for ages before you can start to harvest.
Next, how long does their harvest last in one growing season? We always have peonies in mind as the lowest benchmark – wonderful garden plants, but hopeless in terms of cut-flower production. They take three years to come into full-on harvest and individual varieties crop for only three weeks in one year. For plants to earn their keep in the cutting garden here we expect them to be hugely better than this. Cosmos ‘Purity’ is our benchmark at the other end of the scale, giving 50 buckets of flowers per metre from mid-July until the end of October.
Along with these key judgments we look at more general things. Number three on our “must-have” list is good germination; then ease of growth (and with that an absence of pests and diseases); plus the cost of the crop to harvest; then vase life; and finally number seven on our table – exceptional characteristics, such as unusual colour, good scent or noticeably tall, straight stems.
On the climb
Most of the plants on trial are straightforward cut-flower annuals, but we also have some climbers, always useful to add vertical minarets
to the undulating domes of our annual and perennial borders. And we have a few tubers/bulbs we’re checking out, too.
A few years ago I sowed some cactus-flowered dahlias from seed, wondering if you could really get a whole dahlia patch from just one pack. Most dahlias from seed are hideous – dwarf, over-flowery pygmies, with the proportions all wrong – but the cactus-flowered mix has performed brilliantly, nice in the garden and good as a cut flower.
We’ve trialled it again this year and got exceptional germination; they’ve been in flower since early July, with a good mix of colours, quick and prolific flower production and a better-thanusual dahlia vase life.
Dahlia ‘Bishop’s Children’ is also a good mix from seed, so we’ve had that on trial as well this year. We planted a 50ft slope mixed with the oh-so-good Verbena rigida, which – in my book – way outdoes its taller relation, Verbena bonariensis. The dahlia germination rate was excellent and they’re already in flower from a mid-March sowing. Any bright green-leaved seedlings amongst the dark foliage ones have turned out to have rather acid-yellow flowers so I’d cast these out in future, but the rest give you a good mix of rich, stained-glass-coloured flowers and handsome foliage. Their vase life is short (three days in the heat) but they work well as single stems for a dinner table. They’ve shot to the top of our list for edge-of-path aisle plants.
Reliable and easy
For spring-planted, summer-flowering bulbs, we’ve been experimenting with the brodiaeas (also called Triteleia). I’ve always loved the bright blue variety ‘Queen Fabiola’, and have now taken to the slightly OTT, but pretty striped ‘Foxy’. This looks good in flower arrangements, and then there’s the one-tone-richer blue ‘Twilight’ – that’s my latest favourite.
All the brodiaeas have outstanding vase lives, going on for up to three weeks if you keep them cool. They’re perennial too, coming up reliably year after year. I have some planted around our fruit cage which went in 10 years ago and they’re still hale and hearty, flowering away. They’re inexpensive bulbs (particularly the widely available ‘Queen Fabiola’) and they all seem to be 100 per cent reliable and easy to grow.
I’m always on the look-out for flowering climbers to follow on from sweetpeas, or to clad teepees from the start of summer, and we’ve gone for the thunbergias this season. I’ve long loved the soft apricot ‘African Sunset’, growing it with rhodochiton, one of
my favourite climbers, and have adored the almost neon orange ‘Superstar Orange’ as a new addition this year. It’s a cheering sight lining a path and looks surprisingly good in all lights, despite its brightness.
As another aisle plant, the toadflaxes ( Linaria) have shone supreme here in the last two seasons. I love the scented ‘Sweeties Mix’, the wonderful rich cardinal purple L. maroccana ‘Violet’ and the gentle coloured ‘Peach’, but it’s Linaria ‘Licilia Azure’ which steals the show for me. Mixed with good old honeywort ( Cerinthe major ‘Purpurascens’) there’s no cheaper or quicker combination for containers at any point through the growing season. They both take eight weeks from sowing to flower and continue to bloom well for at least 12 weeks.
And that’s not the only situation in which they perform. I have ‘Licilia Azure’ lining the main cutting garden path this summer. It’s been in flower since May and shows no sign of tiring; it’s not just good for summer as a garden and cut flower, it’s also invaluable for spring. From an early February under-cover sowing, you can have it in flower by the end of March to pick with hyacinths and narcissi. That’s a sprint – and invaluable for it.
Another group we’ve had on trial are some new antirrhinums. ‘Liberty Crimson’ has long been a great performer, but there are reputed to be even better, longer flowering varieties coming on to the market, so we thought we’d compare them. The F1 Sonnet series seems to be excelling so far this season. The four jewel-coloured varieties ( Antirrhinum ‘F1 Sonnet Burgundy’, ‘F1 Sonnet Carmine’, ‘F1 Sonnet Crimson’ and ‘F1 Sonnet Orange Scarlet’) are being put through their paces. We have them inter-planted with the grass Panicum ‘Frosted Explosion’ which we trialled here in 2014; the combination is the crowning glory of the garden today and has been so for over a month.
We had good germination rates from the F1 Sonnets; they were quicker from sowing to flower than my usual standards – ‘Giant White’, ‘Liberty Crimson’ and ‘Night and Day’ – and their vase life seems exceptional. They are lasting for 10 days in water even in the recent heat and – so far – show no sign of rust, common in cut flower varieties when they’re grown organically, as we do. The seedlings were pinched out when a couple of inches tall and seem to be branching well and producing endless new side shoots with good stem lengths. They could be heading for the top of the class.
The final new annual in the cutting garden trial beds – and mixed with the compact Cosmos ‘Sonata White’ in containers – is the new yellow Cosmos ‘Xanthos’. That gave excellent germination and was quick from seed to flower – it has already been in flower for six weeks. It lasts 10 days in the vase and is apparently as floriferous as ‘Purity’. This also looks like it’s heading for 10 out of 10.
It’s been in flower since May and shows no sign of tiring
Seeds from Thompson & Morgan, Chiltern Seeds, Sarah Raven
Impressive performance: cactus-flowered dahlias, above, are good in the garden and as a cut flower; left, Rhodochiton atrosanguineus (purple bell vine) growing up a birch tripod with salvias around the base
Three of a kind: left, Cosmos container including ‘Xanthos’, ‘Sonata White’ and ‘Seashells White’; right, Thunbergia alata ‘African Sunset’ – Blackeyed Susan
Aisle plant: toadflaxes, left and far left, have shone supreme in the last two seasons; right, a bunch of snapdragons, Antirrhinum ‘Sonnet Burgundy’, ‘Sonnet Crimson’, ‘Sonnet ‘Carmine’ and ‘Sonnet Sonnet Orange Scarlet’