Purple Fountain Grass : Pennisetum setaceum ‘Rubrum’

Today, grasses are taking a giant leap forward and one of the more popular cultivar is Pennisetum setaceum ‘Rubrum’ – more commonly known as Purple Fountain Grass.

Grasses are one family of plants that have made an amazing entrance into the horticultural world in the past decade or so. Prior to that the only grass that most gardeners would keep was their hallowed piece of turf. 

Introducing Purple Fountain Grass

Quite noticeably this grass wasn’t on the radar of any home gardener five years ago but since then it has exploded into our yards at an alarming rate. Not to be confined to the home garden, Purple Fountain Grass has also made it into our streetscapes, public parks and gardens almost anywhere that abandoned soil was visible.

Ornamental grasses have been growing in their popularity as more home gardeners try to reduce their water consumption. In the past, xeriscaped gardens consisted predominantly of cacti and succulents so this third family has been a boon for landscape architects and gardeners alike. It has given us all more choice.

How to Grow Purple Fountain Grass

Soil Conditions

Let me start by stating the obvious – grasses are not keen clay dwellers! If you have a clay soil and want to grow Pennisetum setaceum ‘Rubrum’ in your yard then you will have to either grow it in a pot or ammend your soil so that it drains freely.

While some grasses can handle “wet feet” and therefore complement a bog garden most won’t thrive – let alone survive – in a garden where their roots are continually damp.

Watering Requirements

If you have a free draining soil for your fountain grass then watering should be at a minimum. Even in the heat of summer they only require a limited dowsing of not more than once per week. This will allow them to thrive though they can survive quite well with typical rainfall in most mediterranean climes.

Pruning Purple Fountain Grass

Grasses can be pruned two ways; (1) reduced by cutting down the bulk of the foliage to a small clump, or (2) pulling out the spent tails and dead grass. Obviously the first option is the least labour-intensive and easiest way to manage grasses but unfortunately many ornamentals won’t grow well after a pruning of this type.

Fortunately, Pennisetum setaceum ‘Rubrum’ is one of the grasses that appreciates the former style of pruning. If you cut it back to half of its volume at the end of winter or start of spring it should reward your garden with an impressive display throughout the summer months and still have some interest throughout winter.

Growing Purple Fountain Grass as Perennial or Annual

The only determing factor as to whether you can grow Pennisetum setaceum ‘Rubrum’ as a perennial is how cold your winters become. If you regularly get frosts – or worse, some snow cover – then growing fountain grass as an annual would be a far better choice.