As a gardening and landscaping expert, I can confidently say that Pennisetum Rubrum, also known as purple fountain grass, is typically an annual grass in most areas. This means that it completes its life cycle within a single year.
During the growing season, Rubrum exhibits lush green foliage with attractive burgundy or purple-colored plumes. It adds a beautiful touch to any garden or landscape. However, once the fall season arrives and temperatures begin to drop, the grass will start to turn brown and go dormant.
At this point, you have a couple of options. You can choose to leave the grass as it is, allowing it to provide some winter interest to your garden. The dried plumes can create a unique texture and add visual appeal, especially when covered in frost or snow.
Alternatively, if you prefer a neater appearance or if the grass has become unsightly, you can choose to cut it back to the ground. This can be done whenever you deem fit, as there are no strict guidelines for when to perform this task.
It is important to note that Pennisetum Rubrum is a warm-season grass, meaning it thrives in warmer temperatures. In areas where the winter temperatures regularly drop below 20 degrees Fahrenheit (-6 degrees Celsius), the grass may not survive the cold. In such cases, it is best to treat Rubrum as an annual and replant it each year.
However, in regions with milder winter climates, Rubrum may exhibit some degree of perennial behavior. It can potentially survive the winter and regrow in the following spring. In these areas, you can leave the grass as it is and wait to see if it returns in the next growing season.
Personal experience has taught me that Rubrum tends to be more reliably perennial in USDA hardiness zones 9 and above. In these warmer regions, the grass has a better chance of surviving the winter and coming back every year.
While Pennisetum Rubrum is mostly an annual grass, its perennial behavior can vary depending on the specific climate and winter temperatures of an area. It is always a good idea to monitor how the grass responds to winter conditions in your garden and make decisions accordingly.
