There once was a Dormouse who lived in a bed, Of delphiniums (blue) and geraniums (red)”.
AA Milne obviously adored delphiniums and many would agree that they, along with hollyhocks and lupins, are vital ingredients of the quintessential English garden. But these cottage planting stalwarts do cause difficulties for aspiring and experienced gardens alike. I thought delphiniums were just too much work, what with slugs, and the need for strong bracing and deep soil. I have neglected to grow them recently, but have decided to find space and renew my enthusiasm for them.
John Jenkins of Wollerton Old Hall is a seasoned grower. When asked to describe his role he replied: “If you called me the under gardener that would be a promotion.” That description is modest in the extreme. The whole team are perfectionists and all their plants respond accordingly. They have grown delphiniums for 25 years – tall, beautiful, vertical towers. Wollerton’s thin soil is not ideal, so they add lots of compost in early spring when they can physically get to the borders.
As delphiniums need lots of energy they feed with “John’s mixture”. This is one third dried blood, one third Vitax Q4 and one third blood, fish and bone. This mix of ingredients gives instant nitrogen, all-round feed and slow release respectively, and so fulfils the needs of the growing season in one hit.
Jenkins’s next tip is to reduce the number of spikes to not more than seven per plant on an established plant. On a new plant he might only allow two.
To counteract slugs, he buys aluminium sulphate from a chemist and puts two tablespoons in two gallons of water and applies it around the plant when the leaves emerge. The advantage over slug pellets is that this penetrates into the soil. It acidifies the soil and is used as a hydrangea colourant to keep the flowers blue.
Nick Langdon of the renowned nursery Blackmoor and Langdon (blackmore-langdon.com) recommends applying it in the autumn, too, as slugs lay eggs in the crowns of the plant which will devastate young leaves inspring.
Staking is essential: Jenkins’s stakes are cunning but totally effective. He uses a 4-5ft bamboo cane (painted sludgy green) down the back of each plant, put in around May, then later as the plant grows he inserts a thinner, green cane (the ubiquitous type used for indoor plants) into the centre of the cane to extend the height. Green twine is used to secure the plant.
As to cutting down after flowering, they reduce the height to around 70cm – any lower would leave a hole in the border. A second flush of flowers is unwanted – it reduces the plant vigour and is underwhelming anyway. Any later flowers are removed.
At Wollerton they replace plants after about 15 years and grow cuttings only of 'Alice Artingdale’ – a sought-after powder blue double that is rather tetchy so difficult to source. Cuttings taken now, with a tiny slip of the crown and inserted into pure vermiculite in a pot (sitting in a shallow tray of water) in total shade work well. All others they collect from Blackmoor and Langdon as they relish the opportunity of a visit to fellowenthusiasts.
Langdon points out that Delphinium elatum are by far the easiest to grow, far more manageable than the Pacific hybrids. They are hardier and taller, growing to 9ft high. The exceptions being that some of the creams such as 'Butterball’ are slightly weaker. Langdon stresses the need for water in dry summers. Jenkins’s favourites are 'Faust’, 'Tiddles’, 'Nimrod’, 'Skyline’ and 'Butterball’.
Lupins are easier, especially if you get the best plants. Sarah Conibear (who watched Anne Swithinbank eulogising about them on Channel 4 and became inspired) has developed about 30 new cultivars 'West Country Strain’ (westcountry-nurseries.co.uk) which are from Russellstock.
They are truly perennial, but respond best if you split clumps after three years. Gardeners who find they die out, may in fact be growing annuals or have too limy soil. Conibear reckons that firming in young plants well is key and advises not to add manure. They are nitrogen-fixing plants so do not need/want a rich soil – no mollycoddling necessary. A strong tap root means they should not need staking either.
Maybe the biggest problem is aphids, but spray (with soft soap or contact insecticide) as soon as you spot them. You will probably find they only hit on one plant, so you could cut this down and remove it. Some gardeners find that ones such as 'Beefeater’ go on flowering all summer, late May-September. Ideally remove the spent spike, to prevent seed set (these will not come true from seed). Most plants will carry on throwing up laterals all summer and then you can just leave them to die back naturally in autumn. You can buy mail order plants now. I am planting 'Masterpiece’ – perfect plumes of aubergine purple.
Hollyhocks are rarely grown as well as those featured in Beatrix Potter’s books. But Jenkins’s are possibly bigger and better. His towering 8ft giants greet you in July and August (eight weeks of flower) as you enter the garden. His tip for avoiding rust is to remove the first, early leaves now from the stumps as this helps minimise the rust spore population. Rust will always be there, and any leaf that starts to look affected is best removed; it won’t improve just infect. Mulch to prevent spore-splash from the ground. They also spray fortnightly through the season, using the same spray as for black spot on the roses. They leave the plants in situ for three years, feeding them in early spring with “John’s mixture” (about two handfuls a plant) and again in May.
These, like delphiniums, are gross feeders. To replace plants they sow ordinary mixed packets of single-flower seed in autumn in pots, which produce flowers in spring about 18in high. Single hollyhocks are bigger and better than doubles.
They select the colours they want and then plant them out in spring to give them the required colour balance. These large plants need staking (a 4ft plant will not though). When the plant has just started to set seed, they cut them down.
IN MY GARDEN
Have just planted out plugs of mange tout and broad beans, will watch out for cats and birds as they will be lurking. Will sow more broad beans in plugs now too (will balance trays on an overhanging board balanced on a bucket to stop hungry mice).
A hundred Tulbaghia violacea, right, arrived (from Jacques Amand) in the green, with long leaves already (far more advanced than those already growing here) so hurriedly plonked in moist compost in pots in my frost-free greenhouse until conditions are warmer. My star bulbs!
Weeds are starting to appear. Will be on the watch for these (never let them flower) and the slugs.
Time to sow in earnest, lots of different veg in small quantities especially with successional crops. Yacons sprouting well on window sill along with last year’s chilli plants which still have chillies and new flowers.
