Pampas grass is the grass that northern gardeners covet and Southern gardeners worry about escaping into the environment.
Let’s deal with the obvious first. Those of us in the North want to grow it – those in the South should be concerned about controlling it because of its extreme invasiveness and abilty to wipe out native plant populations. Having said that…
Pampas grass is a native to South America, Chile, Brazil and Argentina so you can imagine it is not particularly cold tolerant.
You’re looking at a USDA zone 8 for the most part.
You might get away with a heavy mulch in USDA zone 7 in a mild winter but don’t bet the farm on it. North of that this is an indoor plant for the winter.
How To Grow
This is a grass so think…
Think full sun, fertile and well drained soils and you’ve got the picture.
Having said that, it will tolerate (for short periods) flooding or even drought.
It will adapt to drier gardens once established so don’t worry about it being in sandier soils.
Clay soils will not be appreciated because of the constant winter wet.
Propagation of Pampas Grass
Division in the early spring is the normal way to propagate Pampas grass.
It will germinate from seed but the newer named varieties will not come true from seed.
As an aside, I once obtained seed from three different suppliers and grew out 200 young plants. Tried to overwinter a large number of these outdoors in USDA zone 4 in an “attempt” to find one lonely hardy plant. Result = a large number of rather dead plants in the spring. 🙂
The female flowers are larger and thicker than the male flowers so if you have a chance/choice, pick the females.
Note the leaves of pampas grass are quite sharp and will cut like small razor blades if you get too close to them. Do not plant this one next to swimming pools or pathways.
Pampas grass in early morning light
If you purchase pampas grass, let me suggest you spray it with a fixative (hair spray works well) because as it starts to degrade, it will shed bits all over the place.
Container Growing and Overwintering
Use the largest container you can find and/or afford.
This is a big plant and demands a pot that is at least 18-inches in diameter. There is little point in trying to grow it in anything smaller.
Use an artificial soil in the pot. This is both for the ease of growing as well as for the ease of moving the pot indoors to a frost free area in the fall.
Grow as for any container plant during the summer. Feed it weekly and water it regularly so it doesn’t dry out totally.
If happy, it will put on good growth in the first year but unless you started with a large plant, it will not likely flower the first year.
Note that flowering is initiated by the lowering light levels in the fall, not cold weather.
You have to overwinter it. And here’s the rub. Move this plant to a frost free area but not a hot one. I’m thinking somewhere in the 40’s is ideal. You want it dormant, light is not necessary, but not cold. You don’t want it warm as that will push it into growth.
And unless you have a lot of grow lights, you don’t want it growing too early in the spring. Around March, when the light levels start to rise again, you can bring it into the full (important – full light) southern light and even provide supplementary lighting. You want to mimic natural Southern lighting with its high intensity.
Anything less will give you soft floppy growth. Keep it in the house until the night temperatures warm right up (we’re likely talking June at the earliest) and then put outdoors during the day – taking in at night if cool.
Grow this second year and you’ll likely see flower initiation in the fall. Repeat the wintering process except now you can divide the plant in the early spring and obtain two plants. Watch those leaves (gloves, long sleeves etc. or you’ll learn the hard way).