Posted on | August 9, 2008 | No Comments
Grasses are not normally associated with exotic or subtropical style gardens, which is a shame because they add movement and height to the garden with many of them looking exceedingly tropical in nature. As such they make a good substitute for plants that we can’t grow in our temperate gardens such as the more tropical sugarcane Saccharum officinarum. Or can we?
That was what I thought until I discovered, much to my surprise, some of them lurking at a local garden centre a few weeks ago. Saccharum officinarum violaceum or ‘Purple Sugar Cane’ is a giant perennial grass that forms 2-2.5m (6-8 ft) tall clumps of long, smooth, veined deep purple-bronze leaves up to 1.2m (4ft) long.
I planted a group of these luscious tropicals about three weeks ago as 18ins high plants. They have already reached 1.2m (4ft 6ins) and are all growing at a rate of knots and are well on their way to becoming formidable giants. At this growth rate they should easily reach full height by early autumn.
Even though they can only be used as an annual in this country, their sheer size in a single season makes them excellent bedding plants and they would also look stunning in large containers.
There is sugary cane juice in the pith of the central stalks, but be careful if you reach for it because each leaf has a sharp, jagged edge that can cut if you’re not careful.
There is also an excellent sugar cane lookalike called Miscanthus sacchariflorus. It’s a deciduous, clump-forming, perennial grass growing to a height of 3m (10ft) with flat, linear, arching bluish-green leaves up to 90cm (36in) long, with pale, silver-green mid-ribs. In autumn it takes on alluring warm orangeybrownish tones. Although not fussy, it prefers moderately fertile, well-drained moist soil in full sun and is hardy to at least -10C (14F)
There are so many other grasses available that we are spoilt for choice with the number that fit in seamlessly with this style of gardening. Whether small or tall, they give height, stature and form to the garden, many with a very architectural appearance, and the added attraction that the foliage catches the wind, adding a sense of motion to the landscape.
If space is restricted some of the smaller species and cultivars, such as Hakonechloa, can be used. They look especially good weeping over the sides of pots and containers, giving a very lush feel.
This highly desirable grass is in a genus of just one species of slowly-spreading, rhizomatous perennial, found growing on wet rocky cliffs in the mountainous district of Tokaido in south-east Honshu, Japan. Hakonechloa macra ‘Aureola’ is a very handsome, slowly spreading, loose cascading mound to a height of 30cm (12in) by 51cm (20in) with bright yellow with narrow green stripes, gaining a glorious pinkish red tint in the autumn and persisting through the winter months.
This delightful plant has been growing in a shady corner of the Exotic Garden for over two decades now requiring little attention.
There are also several cultivars of this alluring grass, all having a wonderful flowing form that look very exotic hanging over small walls and containers and by pathways.
They are also useful for brightening dull corners of the garden. They prefer fertile, humus-rich, moist, welldrained soil in sun to dappled shade and are hardy. ‘Albo Striata’ is rare and hard to find, though well worth the hunt. It is a Japanese forest grass that is more sun-tolerant than the golden form. Its pendulous green foliage is adorned with thick and thin creamy white stripes.
Personally, as you may have guessed, I have a passion for the large grasses and one of my favourites has to be Arundo in a genus of three species of evergreen, rhizomatous, perennial grasses found growing on lakes, riversides, streams in their native habitats.
Arundo donax, or Spanish Reed as it is more commonly known, is a majestic clump-forming, rhizomatous well-behaved grass grown in our gardens for its enormous bamboo-like stems and foliage.
Its fleshy, creeping rootstocks form compact masses from which tough, fibrous roots emerge that penetrate deeply into the soil, growing to a height of 5m (16.4ft) in my garden. It boasts stout stems and arching, broadly linear, greygreen, glaucous leaves up to 61cm (24in) long by 7.5 (3in) across. It is also the tallest grass you can grow in the British Isles, giving an impressive appearance which can dominate your garden if let loose!
The variegated cultivars are very attractive indeed, and although less hardy have returned for many years in my garden in Norwich, taking lows of -4C (25F) in their stride. ‘Variegata’, or ‘Striped Giant Reed’, grows to about 2.4m (8ft) tall, with leaves variegated with white stripes. ‘Variegata Superba’, is another beautiful form which has leaves striped and margined in a creamy-white.
Arundos are not particularly fussy about soil type, as long as they are moist and grown in full sun in a sheltered location. For the best foliage, it is advisable to cut growth back to the base annually which produces smaller plants of about 2.4-3m (8-10ft) tall.
If you desire an absolutely enormous plant though, leave the old fronds on and they will form an impenetrable thicket. Feed them a high nitrogen fertiliser and they will probably explode! The foliage dries to light brown in the winter and rattles in the wind. In warm climates, it produces panicles of light green to purple spikelets to 61cm (24in) long from mid-to-late autumn. Though it rarely flowers in the British Isles, it will probably flower in the decades to come as we inevitably warm up! If you are interested in grasses and are not bothered whether these spectacular plants are in or out of fashion, I would suggest investing in one of the many books on the subject that our available.