Why you should have delphiniums in your garden
PUBLISHED: 10:54 20 February 2017 | UPDATED: 10:56 20 February 2017
Delphiniums look regal in any border. Philippa Pearson visits specialist nursery Home Farm Plants in Bovingdon to find out about growing these majestic perennials
One of Graham Austin’s first jobs in horticulture was to sort through perennial plants after winter and throw away the ones that hadn’t survived. It was during this process that he noticed that a particular plant range survived winter after winter, and this was delphinium elatum.
‘I was impressed by the tenacity of these plants,’ he recalls, ‘And while other ranges struggled, these delphiniums seem to thrive in the cold.’
The flower had a lasting impact on Graham and features prominently at his own nursery, Home Farm Plants in the village of Bovingdon near Hemel Hempstead. The nursery is one of only two specialist growers in the country of delphinium elatum.
It’s easy to see why the plant comes back year after year – its native habitat is the Alpine slopes, so it’s perfectly happy with a British winter’s ice and snow and will thrive all the more if the season is particularly cold.
Known as the Queen of the Border for its cottage garden-style blowsy flower spikes in summer, delphinium elatum is hardy, very reliable and easy to grow with a little care and treatment.
‘We grow over 80 different varieties of elatum at the nursery,’ says Graham, who points out that these particular delphiniums shouldn’t be confused with the widely-available Pacific hybrid series – bred as annuals in California, it tends not to survive year to year in English borders. While elatum can survive sub-zero temperatures, one thing it doesn’t like is being too damp. Graham suggests making sure your soil has good drainage before planting, adding horticultural grit if it is heavy or compacted.
Elatum doesn’t grow true from seed so named cultivars are grown from cuttings and this time-consuming process means plants are available only from a handful of specialist growers. More than 2,500 delphinium cuttings are grown each year at Home Farm Plants and work begins in late January and early February in the polytunnels. While some are grown in the field, a little gentle protection is helpful as new plants get established. By March, growth has begun to shoot from the base and these are taken as crown or basal cuttings to form new plants.
‘Crown cuttings is when you take a little piece of the crown of the main plant with the cutting which will help it to get rooted quickly,’ Graham explains.
The young plants are kept in the polytunnel until May, then moved outside, where they will flower from July onwards. As well as traditional blues, the nursery grows shades of pinks, purples, white and cream delphiniums as well as some rare and unique plants.
As you might expect from a plant that begins life in February only a couple of inches tall then grows to a towering eight feet by mid-June, delphiniums are hungry plants. Graham recommends feeding with a general fertiliser like fish, blood and bone in spring and feed regularly during the growing season. In early spring, thin newly planted and remove any weak shoots to achieve a bigger and stronger plant. It’s important to stake delphiniums around April to May before they get too big.
‘Generally three five-foot canes arranged in a triangle around the outer edge of the plant with twine woven around at six, 12 and 18 inches up to form a cage is effective.’ Graham advises.
Don’t tie each stem to individual canes as this will cause them to break – stems need to be able to move.
When flowering has finished, cut spikes down to around six inches below the old flowerhead and feed with a potash fertiliser such as tomato food. This will encourage a new flush of flowers in early autumn. Before winter, cut foliage to ground level and add a layer of sharp sand to help with drainage as well as give protection.
‘With a small amount of care,’ says Graham, ‘you can have these perennials flowering in your garden for 15 to 20 years or more.’
Visit Home Farm Plants
The nursery is open from April 1 to the end of October selling delphiniums as well as a wide range of perennials, all propagated traditionally at the site. It also has a pick-your-own cut flower area where you can choose blooms, including daffodils and tulips in spring, delphiniums and dahlias in summer and asters and gladioli in autumn. Open Friday and Saturday, 9am-5.30pm, Sunday 10am-4pm and Monday to Thursday by appointment. Home Farm Plants attends specialist plant events throughout the season and is open for the National Garden Scheme in July. Check the website for details.
Shantock Lane, Bovingdon HP3 0NG. 07773 798068. homefarmplants.co.uk
Graham Austin’s five delphium elatum to try
After Midnight – abundant mid-blue flowers
Fenella has lovely gentian-blue flowers
Elizabeth Cook – pure white flowers
Rosemary Brock with dusky pink flowers
Emily Hawkins – pale violet flowers
Graham recommends joining the Delphinium Society which has a good range of information and events. See delphinium-society.co.uk