FEATURED PLANTS - RESTIOS

My interest in Restio's began after an extremely interesting day visiting Les Cathry's garden in St. Buryan. There on a windswept site stands an amazing collection of these perennial evergreen rush-like plants, primarily from South Africa. The growth habit varies with some, like Chondropetalum tectorum, having tufts of Juncus like growth while others such as the ever popular Elegia capensis resembles giant horsetails. Giants of the group such as Rhodocoma gigantea and Calopsis paniculata create a wonderful effect with their arching feathery foliage and and bamboo-like stems reaching heights of up to 3m. This group of plants certainly had horticultural potential but the question was "Are they hardy".

Les has been growing these plants for many years where they have come through our occasional hard Cornish winter surviving temperatures down to minus 7 degrees C. In the last few years many have been planted in gardens all around the Uk. Where the cold winter of 2000-2001 saw temperatures in the north drop to minus 12 degrees and below. The feedback from various parts of the country has been good, with some gardens losing all their palms apart from Trachycarpus fortunei and having Cordyline australis cut to ground level yet not losing their restios. Some varieties will go brown in winter but if they have a thick layer of bark or similar as a mulch to protect the roots from frost they should survive all but the coldest winters. If in any doubt wrap them with fleece or something similar to be safe.

The cultivation of these plants is simple, they just require an open, sunny position, not crowded by other plants and plenty of fresh air circulation, not usually a problem in Cornwall. Plant in a well drained acid soil that does not contain too much phosphates. They do respond to the use of slow release fertilizer but on the whole they do not require much in the way of supplementary feeding unless grown in large pots. They are cool season growers, putting on most growth in early spring and autumn even as late as up to Christmas in some years. The growth slows down in the hot summer months enabling them to withstand droughts once established. Growth can be extremely fast with some varieties capable of putting on 6-9ft stems in one year rather like bamboos, with the juvenille feathery growth gradually being replaced with mature stems after several years when they also produce the most attractive dark brown seed heads and beautiful golden brown papery bracts.

The propagation of Restios has been the main reason they are not well known, with germination being extremely difficult until the introduction of Kirstenbosch smoke discs. Seeds of most species are dormant until the seeds are soaked for 24 hours in this specially prepared liquid which basically mimics a Fynbos fire. Division in late winter to early spring is also viable as long as only large divisions are used; Trying to obtain too many plants from a single specimen will usually result in failure.

We have over 50 varieties on trial with the following being the most popular:-

Elegia capensis
Probably the most popular variety, a clump forming plant growing to 2m high bearing an uncanny resemblance to a giant horsetail with dense whorls to thread like branches spread along the fast growing vertical stems. Excellent for cut foliage, the stems last longer in the vase than many conventional varieties like Eucalyptus. Produces golden brown flowers in the spring followed by dark brown seed heads in the autumn. Seems to grow better in a moisture retentive soil that still drains well in winter. An attractive, easy to grow plant that looks good when planted next to ponds or in mixed borders.

Chondropetaum tectorum
Once used in South Africa as a thatching reed this popular variety forms a very attractive fast growing tufted clump with rich dark green stems up to 1.5m tall, giving the appearance of Juncus effusus with the stems radiating in an arc up to 2m wide. A beautiful sculptural plant for growing in any well drained soil even those containing lime. Also makes an excellent plant for growing in large pots and containers.

Rhodocoma gigantea
One of the most attractive of the tall restios, an erect growing plant with arching plumes of bright green feathery foliage topped by fast growing stems up to 3m tall with chestnut brown seed heads from autumn onwards. The stems can grow from soil level to 2-3 meters tall in one season rather like Bamboo, especially in moisture retentive soil. It seems to respond well to extra watering in summer and autumn for exceptionally fast growth.

Rhodocoma capensis
An extremely elegant looking restio up to 1.5m tall and 1m wide. With upright slightly arching plumes of feathery growth covered in tiny brown spikelets when mature, this plant resembles a large flowered pampas grass. A stunning exotic looking plant for mixed borders but can also be grown in large pots and containers in an acid compost using slow release fertilizer at half the normal rates.

Restio tetraphyllus
Also known as the Plume Rush, this Australian variety was introduced to us many years ago by a specialist grower of Australian plants from the North of England who told us that he had been growing it in his garden for years, surviving many harsh winters. It resembles a miniature bamboo as it forms a dense clump of smooth slender stems about 1m high from its rhizomatous roots. The thin bright green thread-like foliage is carried from about half way up each stem. A good sized Restio for tubs and pots using a neutral to acid compost. John Innes no. 3 lightened up with a peat or peat free compost seems to be ideal. In Australia plumes are used commercially as cut foliage in florist shops and flower stalls.

Calopsis paniculata.
A tall growing species spreading to form large groups of finely branched stems much like bamboo culms up to a height of 2-3m. and a spread of 2m. This forms a tussock of exotic growth topped in the autumn by hundreds of light brown spikelets and is another excellent variety that is also used in South Africa as cut foliage.