Several seed companies sell seeds of pink pampas grass (Cortaderia selloana ‘Rosea’) with misleading information that seems to suggest that it could be grown by most gardeners. However, that is not the case.
Here are a few details about this plant… and why it is probably not a good choice for you.
The Original Pampas Grass
Pampas grass (Cortaderia selloana) is a majestic large tussock grass from, as the name suggests, the pampas (grasslands) of South America. It’s quite a whopper: about 6 to 15 feet (2 to 4.5 m) in height and 3 to 8 feet (1 to 2.5 m) in diameter. It produces arching green leaves and thick stalks bearing enormous grayish plumes that turn silvery white in fall and winter. It’s a full sun plant adapted to deep soils and, once established, it is highly drought resistant and couldn’t be easier to manage…
But what it isn’t is hardy.
Various authorities suggest hardiness zones 7 or 8. My guess is that 8 is closer to reality, as prolonged freezes below 20˚F (-7˚C) will kill it, but of course, in protected spots in zone 7, you can certainly try it.
Where Pink Pampa Grass Differs
‘Rosea’ is a selection of the species with flowers that are lightly flushed pink. It’s a smaller plant, about 6 feet by 3 feet (2 x 1 m), and more delicate than the species. Even when well grown, it’s not nearly as impressive or as floriferous. And it’s also a bit less hardy. You’re unlikely to see this plant thriving in climates colder than zone 8.
However, serious “zone creep” has set in for this plant. You’ll see lots of nurseries (although not ones specialized in grasses) offering it as a zone 6 plant. And the seed packets I have seen all have it as zone 5! That’s really, really exaggerated!
What’s also exaggerated is the plant’s color. Many (but not all) seed companies have “improved” the flowers’ color to make it appear bright pink on their packets and websites, not the greyish pink to pinkish white it will actually give you.
Furthermore, it doesn’t not true from seed. When you grow it from seed, you’re never sure what flower color you’ll get. Often seed-grown plants will have little to no pink in their flowers.
Where It Will Grow and Won’t
Pink pampas grass is simply not going to grow well outside of a Mediterranean climate or one with similarly moderate winters. It does fine in southern Europe and those parts of central Europe that are moderated by the Gulf Stream as well as in Australia, New Zealand, South Africa, the US Deep South, the US west coast and even extreme southwestern British Columbia. In the US Midwest, New England, northern Europe or Canada outside of BC, though, just forget it: it’s just not going to happen.
A Dangerous Plant in More Ways Than One
Once you’ve got a handle on this plant’s climatic needs, you now have to consider the potentially negative effects of pampas grass, both the species and ‘Rosea’.
Pampas grass has proved extremely invasive and harmful to natural environments in many countries and is listed in the Global Invasive Species Database. Female plants (C. selloana is dioecious) produce tens of thousands of wind-borne seeds each year and self-sows with abandon. Some reports suggest the seeds can be carried as far as 20 miles (32 km). It’s caused major environmental problems in California, notably.
Eradication programs are underway in many areas where this plant has escaped from culture (California, New Zealand, Australia, France, Spain, etc.).
In addition, this plant is extremely flammable and is therefore not recommended in areas prone to bush fires, such as southern California and Spain. Even the dried flower heads, once very popular as indoor decorations, are serious fire hazards. A few disastrous incidents in it the late 1800s put an end to what had become a thriving industry in dried pampas plume flowers. Those fires have been long forgotten, but it remains a dangerous plant to include in a dried floral arrangement.
The other threat is physical. The leaves have sharp teeth that cut into the skin like a razor. In fact, that’s the origin of the plant’s botanical name, Cortaderia, which means “plant that cuts”. It is not advisable to plant this grass near children’s play areas. If ever you have to work on it, make sure you wear leather gloves with an extra-long cuff reaching at least to the elbow.
Still thinking about growing pink pampas plume? Here are some other things to consider.
1. It may never bloom in your climate. It needs a long summer of about 170 to 220 days in order to bloom. It is therefore unlikely that it will flower in short-summer areas.
2. It makes a crummy houseplant. Yes, you could theoretically overwinter this plant indoors in a heated, sunny room in colder climates and thus save it from the cold, but the plant becomes huge and difficult to handle, uses a lot of space and its razor-sharp leaves makes any effort in moving it about very disagreeable.
I tried this with another cultivar of pampas grass (C. selloana ‘Silver Stripe’, a variety with variegated foliage), but decided to let it freeze after 3 years of efforts. It had become too heavy to lug in on my own and I found dressing up like an astronaut to move it (long sleeves, long pants, closed shoes, rose gloves, goggles and a cap) quite annoying: all that for a plant that didn’t even bloom!
3. Seed-sown plants don’t make good annuals. Although C. selloana ‘Rosea’ seeds germinate readily, the plants produced are too small the first year to make much of an impact in the summer garden, so they really don’t make good annuals.
4. It’s illegal to sell this plant in several areas. If you’re reading this article from California, Hawaii, most US territories, New Zealand, Australia (most parts), South Africa and other areas where this is the case, it would be unethical to buy and plant it.
A Revealing Detail: on one website where readers are asked about their appreciation of the different plants they sell, C. selloana ‘Rosea’ earned only one star out of a possible five.
For most readers of this chronicle, the pink pampas grass is simply not a very interesting plant to grow. Yes, the seed is widely available, probably in a garden center near you, but I suggest you leave it in the store and choose another grass better suited to your growing conditions.