Grassy space invader that won’t go to pot
Some plants were never intended to have their roots constrained in containers.
For the vigorous, the big and confident, confinement is an insult.
Certain plants give their best only when they are growing unfettered. Stick them in a pot – even a big pot – and these plants will grow but they will be pale imitations of their true selves.
So it is with giant reed, Arundo donax versicolor, a very vigorous, half-hardy, perennial grass that once planted will continue to reappear, year after year, and grow in stature until it can become a bit of a problem, spreading to overrun lessaggressive plants.
The simple solution to that potential problem is simply to dig up the offending invaders and compost them or give them away to friends and neighbours – warning them, of course, that the plant(s) needs keeping under control.
Other than that invasive tendency, giant reed is a welcome element to any garden, particularly at the back of a border or against a dark background where its arching, white-striped foliage can be shown off to best effect.
A mature clump can stand almost six feet high and in late summer there’s the bonus of dense, creamy-white seed heads.
This is a plant that demands very little; any well-drained soil suits it, but it does best when planted in full sun and where its roots are guaranteed moisture all year round. That’s why it tends not to flourish in containers – the roots grow quickly and will soon take up all the space available, and if it’s not watered regularly, it will never live up to its true potential.
Cold winds and hard frosts can damage it, but it’s usually hardy enough to shake off the effects of a severe winter and start throwing up fresh, new growth in early spring. When you see this happening, rush out with the shears and cut off all last season’s dead and desiccated foliage.
One word of warning: the plain and simple Arundo donax is a much taller (a mature grouping can reach more than 20 feet in height) and hardier version whose foliage tends to be more blue-green. Known also as the Spanish cane, it can be very invasive, particularly in moist ground.