Echiums of Macronesia

Question: What grows 15 feet in 2 months and likes Canaries? Flushed with success from his recent TV appearance, Richard provides the answer.
Richard Darlow, 106 Vaughn Road, Gawber, Barnsley
Chamaerops No. 16, published online 23-08-2002

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Echium wildprettii on Mt. Teide, Tenerife.

Anyone who has spent a holiday in Tenerife or Madeira, or visited Tresco and the Cornish coast - particularly in late spring or early summer - cannot have failed to notice wonderful tall spires of blue or red flowers. Having seen them, their identity may not always be realised as relatively few horticultural books describe them or give any clue as to their cultural requirements. For several years, I did not know what they were but I'm now pleased to be better acquainted with them; they are species of Echium and belong to the Boragitiaceae - the Borage family.

There are around 40 species of Echium consisting of annuals, biennials and shrub-like perennials. Their distribution is mainly throughout Europe, western Asia, Africa and Macronesia. Flower colour is predominantly blue, but red, pink, mauve and white species are to be found too. Many European species are small growing annuals, which are not particularly showy; the blue flowered British native 'Vipers Bugloss' - E. vulgare - is an example. It is however, those species which are native to Macronesia - that is Madeira, the Canary islands and the Azores - that are most frequently cultivated and which produce the most spectacular of flowers.

There are two distinct types of Macronesian Echium: biennials (or triennials) and shrubs.

The former are monocarpic and produce a rosette of leaves in their first year, which elongates and develops into a flower spike during the second year, but sometimes this is delayed until the third. This mirrors the growth characteristics of common garden plants such as Digitalis and Verbascum. After flowering, large quantities of seed are produced then the plants die. Shrub species of Echium are semi-woody perennials forming large rounded bushes. Each branch radiates from a woody stem; leaves are usually confined to the non-woody tips and are arranged in rosettes. Flower spikes are produced each year from the leaf rosettes - new rosettes developing from the bases of the dead flower spikes.

The largest and possibly the best known and most spectacular species is E. pininana, a biennial from the Canary Isle of La Palma - one of the wettest of these islands - where it grows at altitudes of up to 500m. This species is commonly grown in many coastal Cornish gardens and at Tresco, self-seeding freely (almost like a weed but what a weed!) and is unharmed by most winters on the mainland. Huge rosettes - up to 4 feet across - of green, rough-textured leaves are produced in the first year from seed. Leaves are 2 feet or more in length and S or 6 inches broad, tapering to a point. The undersides are covered in many fine hairy 'spines', which can lodge in your fingers if handled! A stout trunk-like stem develops as the leaves become more widely spaced; the rosette reaching 3 or 4 feet in height by the end of the first year. The stem is also covered in fine white spines but becomes increasingly woody at the base where it can be 3" thick.

During late winter of the second (or third) year, the stein rapidly elongates and the leaves become progressively shorter and narrower; tiny flower buds are formed between the upper leaves and for some way above the leaves. In the space of around 2 months, the plant thrusts upwards to a height of 12-15 feet or even higher, forming a tapering spire of thousands (millions?) of tiny blue flowers. The bell-like flowers have protruding stamens, each one fading to a mauve-pink colour as further flowers continue to open over a long period. The flowers are a haven for bees and invariably become a 'hive' of activity! A single flowering plant is a magnificent sight; a large group is breathtaking.

E. fastuosum is a shrub species forming a mounded dome, S or 6 feet high and the same across. Leaves are 6-8 inches in length and are green with silvery hairs. Masses of flower spikes are produced; each one like a miniversion of E. pininana, 2 or 3 feet in length. They are a darker shade of blue. E. fastuosurriis known as 'Pride of Madeia' and believe it or not, this is where the plant originates! A hybrid between E. pininana and E. fastuosum produces the large blue flower spikes of one parent and the shrubby, branching perennial habit of the other.

Several similar species also originate from Madeira. These include E. candicans, which has blue flowers although it is sometimes regarded as a synonym of E. fastuosum, and E. nervosum. The latter has silver-grey leaves, which are covered in soft silky hairs, while the flowers are pale mauve with red stamens and are borne in small spikes.

From the Canary Isles, shrub types in cultivation include E. webbli, found in woodland at altitudes of 500-1800m on Las Palmas. This densely branched plant has quite broad silvery leaves and small spikes of blue flowers. E. callithyrsum from Gina Caanna has lanceolate or ovate hairy leaves and short, deep blue inflorescences. They grow on cliffs at heights of 800-1500m.

Perhaps the showiest species (and my personal favourite) is E. wildprettii, a biennial, native to Tenerife and La Palma. Growing at altitudes of 1600 - 2000 metres, this 'alpine' can be seen above the winter snow line in the crater of Las Canadas and on the slopes of Mount Teide in Tenerife. The climate here is warm and moist in summer but dry and cold in winter.

Superficially resembling the Hawaiian 'Silverswords' (Argyroxiphium sp.), this plant starts off by producing a rather flat rosette of soft, narrow, silvery leaves, some two to three feet in diameter. The rosette does not elongate until the second or third year when the flower spike rockets upwards to some 10-12 feet. The spike is broader and squatter than that of E. pininana and the flowers are more densely packed, commencing closer to the ground. The most significant feature of E. wildprettii is that it has red or dark pink flowers with red stamens.

All of he species I have described can he seen at Tresco Abbey Garden along with several others. Echiums hybridise freely and many of he plants at Tresco are hybrids, providing a range of flower colours from the palest mauve to the darkest purple and almost every shade of blue in between, All of the Tresco hybrids are referred to as E. x scilfoniensis. Echium pininana has hybridised with E. wildprettii to produce huge pink and mauve flowered forms. If you visit the gardens at 'Fresco in late May, you will find flowering Echiums everywhere!

Macronesian Echiums are not very hardy, but this is only to be expected considering their origins. In addition to the Scilly Isles and Cornwall, they grow well (and become naturalised) in the Channel Islands, the Isle of Wight, and in mild, moist coastal gardens of Devon, Somerset, Wales and Western Scotland. Other favoured parts of Europe include the Mediterranean coast, and along the coasts of Brittany and the Cherbourg peninsular in Northern France. They also grow very well in the warmth of central London. Echiums cams tolerate some frost however and will be little damaged by frosts of -2° or -3°C. Below these temperatures plants will possibly experience defoliation, and are likely to be killed at anything below around -5°C. Even in Cornwall, during the severe weather of February 1991, virtually every Echium plant was killed. Fortunately, many re-appeared due to the large quantities of seed that germinated in the warmer weather and by 1992, there were masses of flowering plants once again.

Readers Comments:

On 5-9-2000 Phil Hudgell wrote:
Propagating Echiums
I also find these plants as fascinating as Palms for their architectural and exotic form. I have often gathered seed from Cornwall of E. Pininana and also E. Wildprettei from Tenerife. They grow from seed easily which is also readily available from several seed sources in UK - Secret seeds in Devon supply many types. I have only managed to get Pininana through one winter here in Surrey(1999) and I had a small flowering,but alas no towering spike! However, the seeds that fell from that time have continued right up to this year(2002) to throw up new seedlings each year - about 6 plants annually although I have probably inadvertendly weeded out others. Obviously a full spike could provide a multitude of plants for some years. One technique that I have discovered in an attempt to keep the stock going is to raise them from cuttings. Often a small side branching will form and I have removed these and immersed the base in water. Roots will soon form and then I have added a compost to the water gradually thickening it up to prevent damage to the sensitive roots. These cuttings will then be of manageable size to overwinter in a greenhouse ready for planting out in the spring. Timing this right may enable the plant to flower in its second year rather than the third.

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