June is the best month to come and look at the beautiful Dry Garden at RHS Garden Hyde Hall. The rains that fall through the winter and spring give the plants a renewed vitality and a crisp freshness - and with so many of them bursting into bloom they make a magnificent sight in a dramatic landscape setting.
We have always encouraged plants to self-seed on the Dry Garden, such as the classic California poppy (Eschscholzia), but we have also tried to grow one or two plants that are slightly trickier to establish. A great example of this is the magnificent giant viper’s bugloss Echium pininana AGM with its huge, towering flowering spikes that sway over the undulating landscape.
This species comes from the Canary Islands and is only frost hardy (-5ºC / 23ºF). While it will grow readily in temperate parts of the UK such as in Cornish gardens and the beautiful Tresco Abbey Gardens on the Isles of Scilly, it is much harder to grow in eastern England with our cold winds and greater degrees of frost.
At RHS Garden Hyde Hall we originally planted several echiums as an experiment in 2008, and during several mild winters they thrived and begun to self-seed. During the cold winters of 2011 and 2012 we lost all the plants but some of the seed remained viable in the soil and germinated again the following year - and now for the first time in a few years they are reaching their full flowering glory.
Echiums are biennials or short-lived perennials with very rough and hairy leaves at the base. In their second year each basal rosette produces a huge flowering spike up to 12ft (4m) tall of small funnel-shaped blue flowers that gradually unravel along the flowering spike. When it finishes flowering, the spike dies back and often the basal rosette will die but new seedlings will emerge. Echiums like to grow in a warm situation where they receive sun all day and are protected from harsh frosts. They also enjoy free draining soil and will struggle to over-winter in cold, wet soil.
The awe-inspiring blue flowering spikes take centre stage in the Dry Garden at this time of year, but also vying for your attention in this arid part of the garden are the beautiful mulleins (Verbascum) with their soft, fluffy grey leaves and bright yellow flower spikes, as well as the dazzling Eschscholzia in their ranges of orange and yellow, and robust perennials such as a Salvia nemorosa ‘Caradonna’ AGM whose dark purple flowers are a wonderful contrast to the bright oranges and yellows.